Next Article in Journal
Systemic Analysis of the Contributions of Co-Located Industrial Symbiosis to Achieve Sustainable Development in an Industrial Park in Northern Spain
Next Article in Special Issue
Plant-Microbe Synergism in Floating Treatment Wetlands for the Enhanced Removal of Sodium Dodecyl Sulphate from Water
Previous Article in Journal
Sustainability and Branding in Retail: A Model of Chain of Effects
Previous Article in Special Issue
Role of Microorganisms in the Remediation of Wastewater in Floating Treatment Wetlands: A Review
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:

Implementation of Floating Treatment Wetlands for Textile Wastewater Management: A Review

Guangxi Key Laboratory of Medicinal Resources Protection and Genetic Improvement, Guangxi Botanical Garden of Medicinal Plants, Nanning 530005, China
Department of Environmental Sciences and Engineering, Government College University, Faisalabad 38000, Pakistan
Department of Biology, College of Science, Jouf University, Sakaka 2014, Saudi Arabia
Department of Biology, College of Science, Princess Nourah Bint Abdulrahman University, Riyadh 11451, Saudi Arabia
Soil and Environmental Biotechnology Division, National Institute of Biotechnology and Genetic Engineering, Faisalabad 38000, Pakistan
Botany Department, Faculty of Science, Tanta University, Tanta 31527, Egypt
Department of Biological Sciences and Technology, China Medical University, Taichung 40402, Taiwan
Authors to whom correspondence should be addressed.
Sustainability 2020, 12(14), 5801;
Submission received: 12 June 2020 / Revised: 13 July 2020 / Accepted: 14 July 2020 / Published: 19 July 2020
(This article belongs to the Special Issue Constructed and Floating Wetlands for Sustainable Water Reclamation)


The textile industry is one of the most chemically intensive industries, and its wastewater is comprised of harmful dyes, pigments, dissolved/suspended solids, and heavy metals. The treatment of textile wastewater has become a necessary task before discharge into the environment. The textile effluent can be treated by conventional methods, however, the limitations of these techniques are high cost, incomplete removal, and production of concentrated sludge. This review illustrates recent knowledge about the application of floating treatment wetlands (FTWs) for remediation of textile wastewater. The FTWs system is a potential alternative technology for textile wastewater treatment. FTWs efficiently removed the dyes, pigments, organic matter, nutrients, heavy metals, and other pollutants from the textile effluent. Plants and bacteria are essential components of FTWs, which contribute to the pollutant removal process through their physical effects and metabolic process. Plants species with extensive roots structure and large biomass are recommended for vegetation on floating mats. The pollutant removal efficiency can be enhanced by the right selection of plants, managing plant coverage, improving aeration, and inoculation by specific bacterial strains. The proper installation and maintenance practices can further enhance the efficiency, sustainability, and aesthetic value of the FTWs. Further research is suggested to develop guidelines for the selection of right plants and bacterial strains for the efficient remediation of textile effluent by FTWs at large scales.

1. Introduction

The major sources of water pollution are industries, domestic discharges, urbanization, pesticides, fertilizers, and poorly managed farm wastes [1,2]. The textile industry significantly contributes to the economy of a country. However, it consumes a large amount of water, and thus generates a larger quantity of wastewater [3]. Textile industry wastewater contains harmful dyes, different pigments, oil, surfactants, heavy metals, sulphates, and chlorides [4]. All these pollutants unfavorably affect the quality of water and aquatic life.
Dyes are key constituents of textile effluent. Textile dyes are considered as one of the worst polluters of our environment, including water bodies and soils [5]. These dyes also have adverse effects on human health. The dyes in textile wastewaters are carcinogenic, mutagenic, and genotoxic for all life forms [6]. Dyes in wastewater hinder the sunlight reaching to water, and thus decrease photosynthetic activity, reduce transparency, and disturb the ecosystem [3,4]. Additionally, different chemicals are used in the textile industry and cause problems for life forms, as well as the environment upon direct contact with them [7]. Existing wastewater treatment technologies are inefficient for the removal of dyes and associated pollutants from wastewater because of their persistent nature and resistance to degradation [8].
Incompletely treated or untreated water is harmful to the environment and other living creatures [9,10]. All types of wastewater should be treated before dumping into open water bodies in order to minimize the spread of water pollution [11]. Textile wastewater can be treated by various methods based upon physical, chemical, and biological approaches. However, the by-products of these treatment processes can be toxic and difficult to dispose of safely [6,12]. Consequently, it is essential to devise and adopt an environmentally friendly and sustainable technique to treat textile wastewater.
Phytoremediation, i.e., use of plants to remove pollutants, is one of the best economical and sustainable approaches for wastewater treatment [13,14]. Plants can take up contaminants from water, soil, and air [15]. Over the past years, different plants have been used to remediate dyes from textile wastewater. Different plants species have different nutrients/pollutants removal potential, and could exhibit great phytoremediation and stress tolerance [15,16,17]. Along with the applications of plants, different eco-friendly mechanisms are now being adopted to treat textile wastewater, and they include plant seeds [18], bacteria [8], fungi [19,20], yeast [21,22], and microalgae [23]. Recently, helminths have also been used to degrade dyes, for example, the nematode Ascans lumbncoides and the cestode Momezia expansa have been found to reduce azo dyes by anaerobic methods [24,25].
Although dyes are resistant to degradation, many microorganisms can completely decolorize and mineralize them [26]. The application of bacteria is an efficient way to treat dyes, as they are not harmful for the environment. Different bacteria have a high ability to degrade different dyes; for example, Pseudomonas sp. and Sphingomonas sp. have been found useful in the degradation of dyes [3]. The specifically adaptive bacteria can produce reductase enzymes that can reductively cut the dyes in the presence of molecular oxygen [27]. In the current scenario, we must seek efficient, eco-friendly, and economical technologies to treat textile wastewater with a minimum generation of waste materials [3]. Application of plants and bacteria has become a sustainable approach for wastewater treatment [18].

2. Potential Pollutants in Textile Wastewater

Textile wastewater contains highly variable dyes that have structural varieties including basic, acidic, reactive, azo, metal complex, and diazo dyes [28]. Typical characteristics of textile effluents include high temperature, the extensive range of pH, chemical oxygen demand (COD), biological oxygen demand (BOD), heavy metals, and a variety of contaminants such as dyes, salts, surfactants, dissolved solids, and suspended solids (Table 1) [28,29,30].

2.1. Dyes

Discharge of wastewater from the finishing and dying process in the textile sector is a substantial cause of environmental pollution [39]. Discharge of dying effluents in the environment is the primary cause of a significant decline in freshwater bodies [40]. Dyes are the substances that, when applied, give color to the substrate by altering the crystal structure of the colored materials. Textile industries extensively use extensive dyes primarily due to their capacity to bind with the textile fibers via formation of covalent bonds [41]. Moreover, dyes are those contaminants that are not only toxic, but they also can change the color of the wastewater [42]. The main environmental risk associated with their use is their subsequent loss during the dying process. Consequently, significant quantities of unfixed dyes are regrettably discharged into the wastewater. The release of toxic textile wastewater causes adverse health risks to humans, plants, animals, and micro-organisms [43].
Colored textile dyes not only degrade the water bodies, but also hamper the penetration of sunlight via water, which causes a decrease in the rate of photosynthesis and level of dissolved oxygen, thereby affecting the whole aquatic ecosystem [44]. Textile dyes are composed of two key elements, auxochromes and chromophores. Chromophores are responsible for coloring the dyes, while auxochromes provide chromophores with additional assistance [45]. Azo dyes are most commonly used among all textile dyes in coloring multiple substrates. They have the large molecular structure, and their degradation products are sometimes more toxic [46]. When they get adsorbed by the soil from the wastewater, they can easily alter the chemical and physical characteristics of the soil. It may lead to a reduction of flora in the surrounding environment. The presence of azo dyes in the soil for a longer period dramatically disturbs the productivity of the crops and also kills the beneficial microbes [44]. Different studies reported that textile dyes also act as carcinogenic, mutagenic, and toxic agents [47,48]. An increase in textile industry means more use of dyes that may lead to severe toxicity disturbing the surrounding environment. Textile dyes pose a major risk to healthy living due to their xenobiotic effects [7]. The textile sector releases huge concentrations of colored effluents into the water bodies without prior treatment. Therefore, saving water from pollutants and prior treatment of textile effluents has indeed received emerging attention.

2.2. Dissolved Solids

Textile wastewater is contaminated heavily with dissolved and suspended solids [28]. Total dissolved solids (TDS) are consistently associated with conductivity and salinity of the water. Estimation of solids in water is a vital factor in making it safe for drinking purposes [49]. The World Health Organization (WHO) sets a minimum limit of 500 mg/L for TDS and 2000 mg/L as a maximum limit [50]. A higher value of TDS corresponds to the extensive use of several human-made dyes [51]. In TDS, soluble salts usually exist as cations and anions. Slight changes in the physiochemical characteristics of wastewater completely change the nature of deposit and ions concentration in the bottom. Higher values of TDS result in extreme salinity upon discharging into the water streams used for irrigation [52]. Much higher values of TDS can significantly produce harmful impacts on the biological, chemical, and physical characteristics of water bodies [51].

2.3. Suspended Solids

Suspended solids are considered as major pollutants in textile wastewater. They contain phosphate, chlorides, and nitrates of K, Ca, Mg, Na, organic matter, carbonates, and bio-carbonates [53]. A higher concentration of suspended solids hinders the prolific transfer setup of oxygen between air and water. Excess of a suspended solid released from the textile effluents can block the breathing organs of aquatic animals [54]. Suspended solid in aquatic medium leads to increasing turbidity, which subsequently results in depletion of oxygen. Likewise, suspended solids also can restrict the necessary penetration of light into the aquatic system, which decreased the capability of various algae and different flora to produce oxygen and food. Suspended solids directly absorb the sunlight, which enhances the temperature of the water and, at the same time, reduces the amount of dissolved oxygen [28]. Durotoye et al. (2018) conducted a study to examine the quality of effluents discharged from the textile industry [55]. It was found that the total suspended solids (TSS) exceeded the set limits specified by the national standards for textile effluents by 10 to 110% in all analyzed samples. Similarly, Ubale and Salkar [56] also reported a higher value of TSS (1910 mg/L) in cotton textile effluents [56]. Discharge of untreated textile wastewater with a higher concentration of TSS may potentially be very toxic for all living organisms.

2.4. Heavy Metals

Effluents from the textile industries comprise of several organic and inorganic chemical, organic salts, dyes, and heavy metals [42]. Heavy metals are more evident and non-biodegradable when released into the surrounding environment. Heavy metals can easily accumulate in the food chain as well [57,58]. High non-biodegradability, toxicity, and biological enrichment of heavy metals pollution has gravely threatened the sustainability of the ecological system and human health [59]. High risk of deterioration in water quality is prominent due to the heavy metal pollution [60].
The existence of heavy metals that greatly characterizes textile effluents. Heavy metals present in untreated textile wastewater can easily accumulate into the bio-system leading to various health repercussions [61]. Discharge of untreated textile wastewater is primarily associated with the concentration of several heavy metals such as Arsenic (Ar), Copper (Cu), Zinc (Zn), Cadmium (Cd), Lead (Pb), Mercury (Hg), Nickel (Ni), Chromium (Cr), and many others [62]. Because of the health hazards of heavy metals, numerous regulations and standards have been introduced to avoid any accumulation of heavy metals that would otherwise be lethal to human. Unfortunately, the discharged untreated textile effluents exceed the admissible limits set for heavy metals, especially in developing countries. As reported by Noreen et al. [63] and Mulugeta and Tibebe [64] the discharge of heavy metals from textile wastewater was high as compared to the permissible limits. Similarly, Wijeyaratne and Wickramasinghe [65] also reported that the concentration of Cu and Zn were higher than the permissible limits. Therefore, it is a matter of extreme importance to remediate these metals from the textile effluents before their discharge into the surrounding environment in order to prevent water pollution.

3. Available Technologies for Treatment of Textile Effluent

Textile effluent can be treated by several chemical, biological, and physical methods and reused for irrigation and industrial processes [66,67]. All methods work in some ways, but they all have some constraints. Textile wastewater remediation techniques include, but are not limited to, filtration, chemical oxidation, flocculation, Fenton’s reagent oxidation, foam flotation, fixed-film bioreactors, anaerobic digestion, and electrolysis [68,69]. Among these coagulation-flocculation are the most commonly used methods [70]. Coagulation is the addition of a coagulant into wastewater to treat it, and is also a popular method of textile wastewater removal [71]. Electrodialysis, reverse osmosis, and ion exchange process are some of the tertiary treatment processes for textile wastewater treatment [72]. Adsorption is remarkably known as an equilibrium separation process and is widely used to remove contaminants [73,74]. Furthermore, advanced chemical oxidation processes are also commonly used for such purposes [66]. In many effluent treatment plants, first chemicals are added to make the wastewater constituents biodegradable. Then biological methods are applied, as biological methods alone cannot treat textile wastewaters up to the standard [67].
In certain cases, a combination of two or more techniques can be used to improve water quality, such as the aeration and filtration after coagulation. Filtration is applied as a tertiary treatment to improve the quality of treated wastewater. Carbon filter and sand filters are used to eliminate fine suspended solids and residual colors [75] Recently, a combination of coagulation and ultrafiltration has been applied for better results [76].
Biological treatments include aerobic treatments (activated sludge, trickling filtration, oxidation, ponds, lagoons, and aerobic digestion) and anaerobic treatment (anaerobic digestion, septic tanks and lagoons) [72]. It also includes the treatment by fungal biomass, such as Aspergillus fumigates, effectively used to remove reactive dyes from textile wastewater [77]. A large number of microbes can degrade dyes, and this approach is gaining momentum [78]. Some of the techniques used previously for textile wastewater treatment, along with their disadvantages, are shown in Table 2.
Though many of these technologies have excellent performance, they have many limitations [67,104]. Many physicochemical treatment options are costly because of the equipment [67]. Conventional treatment methods achieve incomplete removal of dyes and produce concentrated sludge, which causes issue of secondary disposal [72]. In flocculation, the floc is difficult to control, and sludge underneath can re-suspend solids in water [54]. Trickling filters also have drawbacks such as high capital cost and a heavy odor [105].
Comparatively, biological methods have various advantages. They are cost-effective, produce a smaller amount of sludge, and are eco-friendly [106,107]. Ecological engineering has the advantage of being cheap. They are also able to treat non-point source wastewater effluents [107,108]. Though some biological processes also have many limitations, such as they are somewhat lengthy processes, some dyes can be a non-biodegradable, and a large amount of heavy metals in wastewater may hamper the microbial growth [54].

4. Floating Treatment Wetlands for Textile Effluent Treatment

Constructed wetlands are engineered systems composed of emergent plants and microbes with tremendous potential to remediate wastewater. Microbes proved great potential in enhancing phytoremediation potential and tolerance of plants to various environmental stresses [109,110]. Floating treatment wetlands (FTWs) are an innovative variant of constructed wetlands that make use of floating macrophytes and microbes for treatment of wastewater [111,112]. The application of FTWs (Figure 1) is a practical, eco-friendly, sustainable, and economical approach for the treatment of wastewater [112,113]. In addition to their high economic importance [114,115], plants have a key role in wastewater treatment. Mats float on the water surface, and plants are grown on these mats in such a way that the plant’s roots are completely submerged in water and the plant’s aerial parts are above the water [116]. Vegetation is supported on buoyant mats, which make these mats easy to retrofit in any water body where they need to be used [112]. Mostly halophytic grasses are explicitly selected for FTWs due to their rhizome, which can trap air [108,117]. FTWs share properties of both a pond and a wetland system. There is a hydraulic gradient between the bottom of the pond and the plant roots, so that the pollutants are degraded, trapped, and/or filtered by the plant roots and associated bacteria [118]. FTWs make use of plants and associated biofilms to reduce the nutrients load; that is why they are described as biofilm reactors with plants [117].

4.1. Role of Plants

The success of pollutant removal from water largely depends upon the selection of the plant species [119]. Plants play an essential role in the removal of pollutants from a water body. The roots of plants play a significant part in this process. The roots act as a physical filter in a FTWs system. Roots filter the suspended particles in water and settle the filtrates at the bottom of the tank or water pond [111].
The key functions of plant in a FTW are:
  • Direct uptake of pollutants by the roots [120].
  • Extracellular enzyme production by roots [113].
  • Provide a surface area for the growth of biofilm [117].
  • Roots secrete root exudates that help in denitrification [121].
  • Suspended particles are entrapped in the roots [111].
  • Macrophytes also enhance flocculation of suspended matter [113].
Pollutant uptake by the roots of the plants is a significant process of pollutant removal from wastewater [122,123]. Dyes are phyto-transformed and then absorbed by the roots of plants [124]. The physical characteristics of the roots of plants and the nutrient uptake are interdependent/interlinked. The type of medium and nutrients in which the root exists specify the root’s physical characteristics. In FTWs, the roots of the plants remain hanging in water and obtain their nutrition directly from the water. It leads to faster movement of nutrients and pollutants in the water towards the roots, thus leading to their accumulation in plant biomass. In a comparison between original plants and only plant roots in FTWs, the plants exhibited an excellent percentage of pollutant removal than artificial roots [111,125]. It suggests that the roots of the plants release some bioactive compounds in the water, and there is also a change in physicochemical processes in water. These bioactive compounds help in the change of metal species to an insoluble form, and it also enhances sorption characteristics of the biofilm, which help in pollutant removal from water [108]. Plants in FTWs support the activities of microbes already present in the wastewater as plant-microbe interactions play a prominent role in the treatment of water [113,126]. Plant roots provide spaces for the microbial growth that are necessary for water treatment [127].
Nitrogen and phosphorus are important pollutants of wastewater discharged by the textile industry. Several plants in FTWs have found efficient in removing total nitrogen (TN) and total phosphorus (TP) from wastewater [128]. Nitrogen is extracted from water by denitrification and sedimentation, while phosphorus is removed by plant uptake [129,130]. FTWs can also remove particle bind metals easily [130]. The ammonia-oxidizing bacteria and archaea on the rhizoplane have a major role in the nitrification and denitrification process [130,131].
Heavy metals are also present in textile wastewater. Macrophytes can take up these metals from the contaminated water effectively. Phragmites australis has excellent capacity for heavy metals removal from water, which is also a significant constituent of textile effluents [132]. FTWs vegetated with P. australis achieved 87–99% removal of heavy metals from textile wastewater [121]. The vegetation and floating mats minimize the penetration of sunlight in the water and stop the production of algal blooms in the water [133].

4.2. Role of Microorganism

Microbes are a key component of the biogeochemical cycle and energy flow in the aquatic ecosystem [134]. Microbes can decompose and demineralize the organic/inorganic pollutants and play a crucial role in pollutant removal from textile wastewater (Table 3) [135]. Microorganisms possess a different mechanism for the remediation of contaminated water, likely bio-sorption, bio-accumulation, bio-transformation, and bio-mineralization of organic and inorganic pollutants [127,135]. The presence of bacteria and their survival in FTWs, along with their activities, is mainly dependent on the type of plants [35]. In addition to the roots, mats also serve as a growth point for microbes [103]. These bacteria in FTWs can be rhizospheric and endophytic [136]. Rhizospheric bacteria reside outside the plant, and are sometimes attached to plant roots or on floating mats. Whereas endophytic bacteria reside inside the roots and shoots of plants [137]. The microorganisms present on roots and inside the plant tissues aid in the pollutant removal process of plants [138]. Microbes also promote plant growth by stimulating plant growth promoting activities like the release of indole-3-acetic acid, siderophore, and 1-amino-cyclopropane-1-carboxylic acid deaminase. They also solubilize inorganic phosphorous [138,139].
Bacteria have a unique ability to adhere and grow to almost every surface, and form complex communities termed biofilms [117]. The rhizoplane of FTWs release roots exudate to attract microbial cells to form biofilms and maintain large microbial biomass. In biofilms, bacterial cells grow in multicellular aggregates that are contained in an extracellular matrix, such as polysaccharide biopolymers together with protein and DNA produced by the bacteria [140]. This biofilm formation is very beneficial for bacteria themselves, such as resistance to many antimicrobial, protozoan, and environmental stresses [141].
In FTWs, different groups of bacteria have been identified; however, the nature and abundance of the bacterial community may vary depending upon the growth conditions, substrate, growth medium, and plant species [142]. In a study on floating wetland’s plants with Eichhorina crassipes, 40 phyla of bacteria were identified, among these most common was Proteobacteria, followed by Actinobacteria, Bacteroidetes, and Cyanobacteria [143]. In another study, Actinobacteria were found dominant in water samples, while proteobacteria were the largest group of bacteria in roots and biofilms samples of a floating wetland planted with Canna and Juncus [142]. The second-largest group of bacteria found in water and roots samples was Cyanobacteria, but was not found in biofilm. The roots of floating macrophytes also harbored the sulfate-reducing and sulfur-oxidizing bacteria [144]. In FTWs, the production of reduced sulfide acts as potential phytotoxin and sulfur oxidizing bacteria contribute in the detoxification of plants [142,145]. The presence of nitrosamines on the plants roost also confirms the abundance of nitrifiers in the aquatic system that contribute to the ammonia-oxidation process [142]. The anoxic and anaerobic microbes ubiquitous on floating mats, soil, and roots contribute to denitrification and retain metals, and thus remove pollutants from contaminated water [146,147]. The metals acquired by bacteria can be sequestered through bioaccumulation and adsorption by binding to different functional groups such as carboxylate, hydroxyl, amino, and phosphate offered by cell walls [148].

5. Removal of Pollutants

5.1. Removal of Dissolved and Suspended Solids

Textile effluents usually contain a high concentration of total dissolved solids (TDS) as compared to the other industrial discharge mainly due to dying, bleaching, and fixing agent. TDS is correspondingly related to conductivity and salinity of the water [49,166]. Similarly, total suspended solids (TSS) consist of nitrates, phosphates, carbonates, and bicarbonates of K, Na, Mg, Ca, salt, organic matters, and other particles. The maximum concentration of TSS in textile effluents is due to the increased concentration of suspended particles, which increases the turbidity of the water [111,124]. It also erases the level of oxygen from the aqueous medium, resulting in the disturbance of principal food chain balance in the aquatic ecosystem [166]. The much higher value of TDS was observed in textile wastewater from an extended range of 1000–10,000 mg/L [167].
In general, total dissolved solids (TDS) and total suspended solids (TSS) are removed via the filtration and physical settling in FTWs. Plant roots have a crucial role in extracellular trapping of suspended solids and the pollutants in order to neutralize the risk and avoid cell injury [168]. In FTWs, plant roots provide a living, high surface area for the effective development of successive biofilms that hold several communities of micro-organisms responsible for entrapping and filtering of suspended particles [111,169]. The root-related network of biofilms has proven active in physical trapping of fine particulates [170]. The presence of disturbance-free atmosphere and unrestricted water layers among the floating roots provides idyllic conditions for sedimentation of particles [171]. Floating treatment wetlands demonstrated productive potential to remediate TDS, TS, TSS, and other suspended pollutants from various types of wastewater [139,172]. Tara et al. (2019) reported an effectual decline of TSS from 391 to 141 mg/L, TDS from 4569 to 1632, and TS from 4961 to 1733 by using FTWs for textile wastewater treatment [35]. Another report showed the achievement of FTWs applied for textile wastewater remediation, showing a significant decline in TDS and TSS after the end of the experiment [173]. The presence of microbial community directly affects the treatment performance of wetland treatment systems [174]. Key role of microbial communities in the effective removal of suspended solid particles is evident by different studies of FTWs [132,146,175].

5.2. Removal of Organic Matter

In textile wastewater substantial organic matter load is present in terms of biological oxygen demand (BOD) and chemical oxygen demand (COD). Wastewater effluents from the dyeing and printing systems are distinguished by significant BOD and COD fluctuations. Dye wastewater with high concentrations of COD and BOD will lead to eutrophication in the receiving water bodies, and raise environmental concerns about possible toxicity [176]. Various recent studies reported a high concentration of BOD and COD in textile wastewater effluents [177,178,179].
In different forms of wastewater, effective removal of organic matter by application of FTWs has been achieved. Darajeh et al. 2016 reported 96% and 94% reduction in BOD and COD from palm oil mill effluents treated with FTWs [180]. Queiroz et al. (2019) treated dairy wastewater by employing eleven different species of floating aquatic plants and observed a considerable reduction in both BOD and COD [71]. Recently, plant-bacteria partnership in FTWs proved to be very promising in the successful removal of organic matter. The maximum reduction in BOD is attributed to the microbial degradation of organic components coupled with the ample oxygen supply in the root zone [181]. Adsorption, sedimentation, and microbial degradation are the primary mechanisms for the effective removal of BOD [182,183]. Meanwhile, reduction of COD is credited to microbial degradation of substrate through plant roots [146,184]. Microbial activities are usually more vigorous in the root zone [158]. Plants roots provide an active settling medium and surface area for essential attachment and food for microbial population [185].

5.3. Removal of Heavy Metals

In FTWs, different processes such as adsorption, the formation of metal sulfide, direct accumulation by plants, algae, bacteria, and entrapments by biofilms in the roots zone play a promising role in successful remediation of heavy metals [123,130]. Various potentially toxic heavy metals settle down in the system bottom once they bind with minute clay particles in the roots zone [186,187]. Endophytic and rhizospheric microbes performed a variety of important chemical reactions, including adsorption, chelation, complexation, sulfide formation, and micro-precipitation, reduction-oxidation, and ion exchange [188]. Root exudates in the root zone speed up these reactions for the subsequent formation of metals hydroxide and sulfide, which in turn improve the sorption of trace heavy metals [189,190].
Recent studies have shown that successful inoculation of various degrading bacteria improves the efficiency of aquatic wetland plants in removing metal ions/metalloids from textile wastewater, resulting in safe disposal or reuse of treated wastewater [172,191]. When bacteria enter into plant tissues, they offer more productive effects for plants as compared to those bacteria present outside the plant body. Endophyte bacteria increase contaminant accumulation and reduce their phytotoxicity in the host plant by mineralizing recalcitrant elements that would be otherwise not degradable by plants [136]. Combining use of plant and endophyte bacteria is a promising approach in the remediation of heavy metals [126,192]. In line with the prospect mentioned above, Tara et al. (2018) determined the positive impacts of bacterial augmentation on two FTWs plants, Phragmites australis and Typha domingensis. Bacteria partnership with T. domingensis reduced copper to 0.009 mg/L, nickel to 0.034 mg/L, chromium to 0.101 mg/L, lead to 0.147 mg/L, and iron to 0.054 mg/L, while P. australis decreased copper to 0.007 mg/L, nickel to 0.027 mg/L, chromium to 0.032 mg/L, lead to 0.079 mg/L, and iron to 0.016 mg/L from their initial concentrations [35].

6. Factors Affecting the Performance of FTWs

6.1. Plant Selection

The selection of the right plants at floating mats is essential to achieve optimal remediation of pollutants. The plants for the vegetation of FTWs should be a non-invasive, native species, perennial, with a quick growth rate, extensive root system, high biomass yield, high tolerance to pollutants, and high ability to uptake and accumulate pollutants in above-ground parts, and which can grow in a hydroponic environment [118,193,194]. The roots’ morphology, plant tolerance to pollutants, and root exudate profile play a major role in determining the plant’s potential for phytoremediation [119]. Many kinds of grass are selected for phytoremediation due to their dense root structure that can harbor a vibrant microbial community. The production of root exudate and its quality also vary significantly even in closely related genotypes. It results in substantial differences in associated microbial community and their stimulation in the rhizoplane [195,196]. Thus, the selection of the right plant in FTWs increases the remediation performance, such as cattails (Typha spp.) are specially used for the treatment of acid mine drainage [197,198]. However, FTWs are planted with several species, and there is no precise pattern of using specific species for certain types of wastewater or pollutants [199,200]. In the past, various plant species have been used effectively in FTWs (Table 4).
Each plant species has a different phytoremediation potential and different metals uptake mechanisms such as accumulation, exclusion, translocation, osmoregulation, distribution, and concentration [201]. Different types of vegetation can be used in FTWs such as terrestrial, aquatic emergent, sub-emergent, and free-floating species. However, emergent plants are most widely used in FTWs due to their extensive root structure [201,202].
The terrestrial and emergent plant species have mostly long and extensive root structures as compared to free-floating aquatic plants, and provide ample surface area for the pollutant removal process [203,204]. The dense root structure and ability of plants to grow hydroponically are important to obtain maximum pollutant removal by FTWs [116].
It is well reported that plants with small root structure and slow growth rates are not suitable for phytofiltration [218]. The dense root structure also favors the bio-adsorption and biochemical mechanism essential for the pollutant removal process [219]. Although terrestrial plants demonstrated good potential for phytoremediation in the hydroponic system, they were not commonly used in FTWs [201]. Species with good potential for rhizo-filtration, such as Brassica juncea and Helianthus annus, can be used in FTWs. The most commonly used emergent plants genera/species are Phragmites (Phragmites australis), Typha (Typha angustifolia, Typha latifolia), Scripus (Scripus lacustris, Scripus californicus), Juncus, Eleocharis, Cyperus, and Elode [33,146,220]. Among all these Phragmites australis is the most frequently used species in free water surface wetlands followed by Typha (T. angustifolia and T. latifolia) [221]. The features such as perennial, flood-tolerant, toxic pollutants tolerant, extensive rhizome system, and rigid stems make it the best contestant for wetlands [204].
A combination of more than one species of plant has also been used many times to see the effect of using multiple species instead of one. Moreover, different plants have different pollutant capacities that vary from species to species. Under same conditions Typha angustifolia removes more nutrients from wastewater as compared to Polygonum barbatum [133]. P. australis produced the highest amount of biomass, followed by T. domingensis, B. mutica, L. fusca, C. indica, and R. indica, whereas L. fusca showed the highest plant density followed by B. mutica, P. australis, T. domingensis, C. indica, and R. indica [108,213]. Plants can uptake dyes, which are the principal constituent of textile wastewater. Previously, Myriophyllum spicatum and Ceratophyllum demersum species of plants efficiently removed dyes from synthetic textile wastewater [10].

6.2. Plant Coverage

Plant coverage on a floating mat has a prominent role in the wastewater remediation process. An increase or decrease in plant density may also increase or decrease the decontamination process. However, an increase in plant density does not equate with an increase in pollutant removal [118]. The increasing plant density will ultimately decrease the dissolved oxygen level of water under the floating mats. In a constructed wetland dominated by cattails and reeds, results indicated that microbial community and nitrate removal rates were high in wetlands with 50% plant coverage than 100% plant coverage [222]. Chance and White [223] reported that non-aerated floating wetlands with 100% planting coverage had a low dissolved oxygen level as compared to floating wetlands with 50% planting coverage. The dense plant coverage limits the gaseous exchange, which mostly occurs through the uncovered portion of the system [223]. There is little information in the literature on plant density, but plant coverage is suggested to be less than 80 percent for most FTWs [224].

6.3. Aeration and Dissolve Oxygen

In constructed wetlands, the dissolved oxygen level is an essential factor that can influence the pollutant removal process. In traditional wetlands, often the problem of insufficient oxygen supply and inappropriate oxygen distribution are found [225]. The atmospheric reaeration is one of the most important sources of oxygen supply in wetlands. Plants produce oxygen during the photosynthesis process, which can be released from plant leaves and roots into their surrounding environment [226]. The microbial degradation of organic matter can be achieved under both aerobic and anaerobic conditions. The aerobic degradation is mostly applied for less polluted wastewater to achieve high removal efficiency, and anaerobic conditions are favorable for the treatment of highly polluted wastewater [227]. It is well reported that higher oxygen contents in wetlands enhance the organic pollutant degradation process [228]. In wetlands, mostly oxygen is consumed by the organic matter degradation and left insufficient oxygen for the nitrification process and total nitrogen removal process [229]. The phosphorus removal bacteria in constructed wetlands can uptake more phosphorus in aerobic conditions as compared to anoxic conditions [230].
The leakage of oxygen from roots facilitates oxygen in FTWs. The extensive roots system, attached microbial communities, organic growth media, and organic pollutants under floating mats develop a substantial requirement of oxygen [223]. In addition, the photosynthesis process in water, gaseous exchange, and aeration may be reduced due to limited sunlight and air circulation, depending on the coverage area of the floating mat. It may lead to a low oxygen level under the floating mats [118]. It is widely reported that water under planted floating mats had a low dissolved oxygen level as compared to floating mats without plants or with artificial roots [111,116,217].
However, an increase in oxygen level does not mean an equal increase in the pollutant removal process. In some cases, the increasing level of oxygen in wetlands did not result in increased removal of total nitrogen and total phosphorus [231,232]. Similarly, in FTWs augmented with biofilm, the increased aeration improved the ammonium and phosphorus removal from polluted river water. In contrast, this increasing dissolved oxygen level decreased the denitrification process and overall total nitrogen removal [233]. In another study, while treating the nutrients enriched agricultural runoff, the aerated water column achieved less nitrogen and phosphorus removal as compared to the non-aerated water column [223]. Although aerated and non-aerated systems removed an almost similar amount of ammonia and nitrate, the aerated system showed higher uptake of nitrogen by plants than the non-aerated system. Park et al. (2019) treated the domestic wastewater through aerated and non-aerated FTWs coupled with biofilms and concluded that aerated FTWs with biofilms enhanced the organic matter, nitrogen, and E.coli removal [211]. Furthermore, it showed that FTWs can effectively perform under aerobic as well as anaerobic conditions.

6.4. Bacterial Inoculation

Plants-microbes interaction in FTWs has been widely studied [211,234,235], and signified the crucial role of plants-microbes interaction in mitigating the pollutants from wastewater. The plants and microbe interaction in wetlands largely depend upon plant species, availability of nitrogen, phosphorus, and various nutrients and minerals. Many plant species could cope with the adverse impacts of heavy metals and other abiotic stresses via regulating their antioxidants and nutrient uptake [236,237,238]. In FTWs, the hanging roots of the plants provide surface area for microbes’ attachment and biofilm formation. Where these bacteria contribute to pollutant removal process and, in return, get organic carbon and oxygen from plants for their growth and survival [169]. Often, these symbiotic bacteria are not competent enough to remediate the diverse and potentially toxic pollutants from the wastewater [231]. The remediation potential of FTWs can be enhanced by inoculating the plants with purposefully isolated bacterial strains [232]. These inoculated bacteria not only enhance the pollutants remediation process, but also reduce the pollutants induced toxicity in plants and favor the plant growth by secreting multiple plant growth promoting hormones.
Rehman et al. [175] reported that the inoculation of FTWs with hydrocarbon-degrading bacteria enhanced the remediation of oil field contaminated water. Further, this plant-bacteria synergism improved the plant growth by reducing level of hydrocarbon induced toxicity in plants by producing siderophores and indole acetic acid and some other enzymes. Similarly, the inoculation of plant roots with rhizospheric and endophytic bacteria enhanced the removal of potentially toxic metals from the polluted river water and metals uptake and accumulation by plants [123]. Tara et al., 2019 applied FTWs vegetated with P. australis in combination with three dye degrading and plant growth promoting bacteria to treat textile effluent. The combined application of P. australis and bacteria enhanced the organic and inorganic pollutant removal and showed a reduction of 92% in COD, 91% in BOD, 86% in color, and 87% in trace metals [35]. Dyes degrading bacteria with the ability to degrade dyes can be isolated from the effluent of textile mills. Bacteria were isolated from textile effluent to degrade reactive dyes and it was found that three bacterial species, Alcaligenes faecalis, Bacillus cereus, and Bacillus sp., exhibited the potential to achieve more than 25% decolorization [239]. The bacteria can also be isolated from the plant parts to use as inoculum in FTWs for the degradation of textile effluent [38]. Some examples of successful application of bacteria in FTWs are given in Table 5.

7. Care and Maintenance of FTWs

FTWs can be constructed by using different types of materials including polyvinyl chloride (PVC) pipes, bamboo, polystyrene foam, wire mesh, fibrous material, and many more [116,127]. The most critical factors that should be considered while selecting appropriate material are buoyancy, durability, performance, eco-friendly, local availability, and cost [116,206]. In general, buoyancy is provided by floating mats/rafts, which also provide the base for plantation of vegetation. Sometimes plants can be grown in other structures such as wire mesh structure, and buoyancy can be provided by different materials such as PVC pipes [116,240]. The floating mats should be strong enough to support the load of plants, growth media, and be resistant to damage by sun, water, and heavy wind for long term sustainability. Floating mats should be designed to extend over the width of the retention pond, making a closed area between the inlets and FTWs for better flow distribution and to prevent short-circuiting [118,223].
The plants can be established on floating mats by direct seeding, planting cuttings and seedlings of the plants. The choice of method depends upon plant species, the structure of the floating mat, and environmental conditions, and availability of plants [118,171]. Direct seeding may be a cost-effective and rapid method for the vegetation of large-scale FTWs. The species, such as Typha and Phragmites, are commonly vegetated on floating mats through their cuttings [146]. The planting of seedlings may be an expensive approach in the sort-term, however, it results in rapid establishment of plants and a high growth rate. For plants establishment, selection of appropriate growth media is very important, especially during the initial stage of the plant vegetation. The most commonly used growth media are coconut fiber, peat, and soil [118,127]. The organic and inorganic fertilizers are also often applied to ensure better growth and development of plants on floating mats [136]. Care should be taken that growth media must have the ability to hold enough water for plant uptake and air circulation to maintain aerobic conditions, be resistant to waterlogging, and have ideal pH for plant growth [118,223].
It is suggested to avoid tall plants for FTWs, as during windy periods, these plants may cause the floating mat to drift, and laying of these plants in one direction may cause the salting or turnover of the floating mats [118,171]. Further, the plants with lose and large above-ground biomass should be avoided to limit the accumulation of dead plant biomass and release of accumulated pollutants in the water column [118]. Care should be taken while planting that plant roots should be able to reach the water column to ensure the availability of water during the initial stage of development [119,127]. After initial days of plantation, some plant may die due to unfavorable environmental conditions or toxicity of polluted water. Additionally, plants may die back during regular weather changes and by severe deoxygenation conditions below the floating mats. This issue can be solved by replanting the new plants at the free area of the floating mats [130]. Periodic trimming and harvesting of the plants may boost plant growth and prevent the accumulation of plant detritus and biomass on the floating mats [168].
Floating mats should be secured appropriately in the aquatic ponds to prevent drifting due to wind and waves [116]. The floating mats can be supported by fastening the floating mat’s corners to the side of the ponds and anchoring them. Care must be taken to ensure that there should be some flexibility in the anchored ropes to adjust floating mats with changing water levels to the prevent sinking or submerging of floating mats during rising water level. In the windy area, the chances of over-turn of floating mats can be minimized by installing small floating mats rather than a large one with low height vegetation [118]. In a warmer climate, vegetation on floating mats may become a habitat for mosquito and other similar insects. This problem can be controlled by maintaining aerobic conditions in the pond, water spray on plants, frequent harvesting of the plants, and by use of approved chemical and biological control agents for these insects [241,242]. The periodic harvesting of the plants also improves the ability of plants to uptake nutrients and phosphorus from the polluted water.
The growth of invasive species on the FTWs may pose a potential issue for specific vegetation. The predominance of selected species can be maintained by regularly checking and pulling the weeds from the floating mats [243,244]. Regular monitoring of the FTWs is also vital to maintain the aesthetic value and prevent the clogging of inlet and outlet by the accumulation of plastic bottles, plant branches, and other non-biodegradable materials [118].

8. Conclusions and Recommendations

FTWs can be a viable option for remediation of textile wastewater as an alternative to costly and partially effective conventional wastewater treatment methods. The combined action of plants and associated biofilm in FTWs can efficiently remove the solid particles, organic matter, dyes, pigments, and heavy metals. The P. australis and T. domingensis have been widely used for FTWs and found efficient for remediation of textile effluent. FTWs are cost-effective, but need proper care and maintenance for long term performance. The harvesting of plants on floating mats can further boost the pollutant removal process and reduce the addition of litter and plant material in water.
The manipulation of characteristics such as plant selection, biofilms, plant coverage, and oxidation/aeration can be used further to enhance the remediation potential of FTWs. The development of guidelines for the right selections of plants for specific types of textile effluents can increase the success rate of FTWs. Further research is required to isolate and characterize the specific bacterial strains capable of colonizing the plants for remediation of textile effluent according to pollutant load. One of the main hindrances in the application of FTWs is the availability of land, which can be solved by the installation of FTWs on already existing water ponds.
Most of the studies conducted on the application of FTWs for treatment of textile effluent were on lab or pilot scale for a short duration. Therefore, it is suggested to research large scale application of FTWs for remediation of textile wastewater under natural environmental conditions. Further, the effect of weather should be deeply observed to analyze the performance of FTWs under changing temperature, precipitation, and other environmental conditions. The proper disposal of harvested plant biomass and litter also needs extensive research for safe disposal of extracted pollutants from the treated wastewater. The use of harvested grasses from the floating mat as the fodder of livestock needs careful investigation of nutritional values of plants, accumulated pollutants in plant parts, and the ultimate effect on animal and animal products and transportation in the food chain.

Author Contributions

This review article was written by F.W., M.J.S., S.A. and Z.A. The data was collected and coordinated by A.K., M.A.E.-E., K.W., and I.E.Z. The manuscript was reviewed, edited and revised by M.R., M.A., M.A.E.-E., and G.S.H.A. All authors have read and agreed to the published version of the manuscript.


This work was funded by Guangxi Natural Science Foundation (2018GXNSFBA294016), Guangxi Innovation-Driven Development Project (GuiKe AA18242040), “Guangxi Bagui Scholars” and Research Innovation Team Project (GuiYaoChuang2019005).


The authors are also grateful to the Higher Education Commission (HEC) Islamabad, Pakistan, for its support.

Conflicts of Interest

The authors declare no conflict of interest.


  1. Owa, F. Water pollution: Sources, effects, control and management. Mediterr. J. Soc. Sci. 2013, 4, 65. [Google Scholar] [CrossRef]
  2. Keiser, D.A. The missing benefits of clean water and the role of mismeasured pollution. J. Assoc. Environ. Resour. Econ. 2019, 6, 669–707. [Google Scholar] [CrossRef] [Green Version]
  3. Júnior, M.A.C. Advances in the Treatment of Textile Effluents: A Review. OALib. J. 2019, 6, 1–13. [Google Scholar] [CrossRef]
  4. Hussein, F.H. Chemical Properties of Treated Textile Dyeing Wastewater. Asian J. Chem. 2013, 25, 9393–9400. [Google Scholar] [CrossRef]
  5. Khandare, R.V.; Govindwar, S.P. Phytoremediation of textile dyes and effluents: Current scenario and future prospects. Biotechnol. Adv. 2015, 33, 1697–1714. [Google Scholar] [CrossRef]
  6. Ayadi, I.; Souissi, Y.; Jlassi, I.; Peixoto, F.; Mnif, W. Chemical synonyms, molecular structure and toxicological risk assessment of synthetic textile dyes: A critical review. J. Dev. Drugs 2016, 5, 2. [Google Scholar] [CrossRef] [Green Version]
  7. Rovira, J.; Domingo, J.L. Human health risks due to exposure to inorganic and organic chemicals from textiles: A review. Environ. Res. 2019, 168, 62–69. [Google Scholar] [CrossRef] [PubMed]
  8. Saratale, R.G.; Saratale, G.D.; Chang, J.-S.; Govindwar, S.P. Bacterial decolorization and degradation of azo dyes: A review. J. Taiwan Inst. Chem. Eng. 2011, 42, 138–157. [Google Scholar] [CrossRef]
  9. Khan, S.; Malik, A. Environmental and health effects of textile industry wastewater. In Environmental Deterioration and Human Health; Springer: Berlin/Heidelberg, Germany, 2014; pp. 55–71. [Google Scholar]
  10. Yaseen, D.A.; Scholz, M. Textile dye removal using experimental wetland ponds planted with common duckweed under semi-natural conditions. Environ. Prot. Eng. 2017, 43, 39–60. [Google Scholar] [CrossRef]
  11. Crini, G.; Lichtfouse, E. Advantages and disadvantages of techniques used for wastewater treatment. Environ. Chem. Lett. 2019, 17, 145–155. [Google Scholar] [CrossRef]
  12. Kalra, S.S.; Mohan, S.; Sinha, A.; Singh, G. Advanced Oxidation Processes for Treatment of Textile And Dye Wastewater: A Review; 2nd International Conference on Environmental Science and Development, 2011; IACSIT Press: Singapore, 2011; pp. 271–275. [Google Scholar]
  13. Ashraf, S.; Ali, Q.; Zahir, Z.A.; Ashraf, S.; Asghar, H.N. Phytoremediation: Environmentally sustainable way for reclamation of heavy metal polluted soils. Ecotoxicol. Environ. Saf. 2019, 174, 714–727. [Google Scholar] [CrossRef] [PubMed]
  14. Anning, A.K.; Akoto, R. Assisted phytoremediation of heavy metal contaminated soil from a mined site with Typha latifolia and Chrysopogon zizanioides. Ecotoxicol. Environ. Saf. 2018, 148, 97–104. [Google Scholar] [CrossRef] [PubMed]
  15. Jeevanantham, S.; Saravanan, A.; Hemavathy, R.; Kumar, P.S.; Yaashikaa, P.; Yuvaraj, D. Removal of toxic pollutants from water environment by phytoremediation: A survey on application and future prospects. Environ. Technol. Inno. 2019, 13, 264–276. [Google Scholar] [CrossRef]
  16. El-Esawi, M.A.; Al-Ghamdi, A.A.; Ali, H.M.; Ahmad, M. Overexpression of AtWRKY30 Transcription Factor Enhances Heat and Drought Stress Tolerance in Wheat (Triticum aestivum L.). Genes 2019, 10, 163. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  17. El-Esawi, M.A.; Alayafi, A.A. Overexpression of rice Rab7 gene improves drought and heat tolerance and increases grain yield in rice (Oryza sativa L.). Genes 2019, 10, 56. [Google Scholar] [CrossRef] [Green Version]
  18. Khamparia, S.; Jaspal, D.; Malviya, A. Optimization of adsorption process for removal of sulphonated di azo textile dye. OPTIMIZATION 2015, 1, 61–66. [Google Scholar] [CrossRef]
  19. Ali, N.; El-Mohamedy, R. Microbial decolourization of textile waste water. J. Saudi Chem. Soc. 2012, 16, 117–123. [Google Scholar] [CrossRef] [Green Version]
  20. Wesenberg, D.; Kyriakides, I.; Agathos, S.N. White-rot fungi and their enzymes for the treatment of industrial dye effluents. Biotechnol. Adv. 2003, 22, 161–187. [Google Scholar] [CrossRef]
  21. Feng, C.; Fang-yan, C.; Yu-bin, T. Isolation, identification of a halotolerant acid red B degrading strain and its decolorization performance. Apcbee Procedia 2014, 9, 131–139. [Google Scholar] [CrossRef] [Green Version]
  22. Mahmoud, M. Decolorization of certain reactive dye from aqueous solution using Baker’s Yeast (Saccharomyces cerevisiae) strain. HBRC J. 2016, 12, 88–98. [Google Scholar] [CrossRef] [Green Version]
  23. El-Kassas, H.Y.; Mohamed, L.A. Bioremediation of the textile waste effluent by Chlorella vulgaris. Egypt. J. Aqua. Res. 2014, 40, 301–308. [Google Scholar] [CrossRef] [Green Version]
  24. Rather, L.J.; Akhter, S.; Hassan, Q.P. Bioremediation: Green and sustainable technology for textile effluent treatment. In Sustainable Innovations in Textile Chemistry and Dyes; Springer: Berlin/Heidelberg, Germany, 2018; pp. 75–91. [Google Scholar]
  25. Chung, K.T.; Stevens, S.E., Jr. Degradation azo dyes by environmental microorganisms and helminths. Environ. Toxicol. Chem. Int. J. 1993, 12, 2121–2132. [Google Scholar]
  26. Sandesh, K.; Kumar, G.; Chidananda, B.; Ujwal, P. Optimization of direct blue-14 dye degradation by Bacillus fermus (KX898362) an alkaliphilic plant endophyte and assessment of degraded metabolite toxicity. J. Hazard. Mater. 2019, 364, 742–751. [Google Scholar]
  27. Stolz, A. Basic and applied aspects in the microbial degradation of azo dyes. Appl. Microbiol. Biotechnol. 2001, 56, 69–80. [Google Scholar] [CrossRef]
  28. Kumar, P.S.; Saravanan, A. Sustainable wastewater treatments in textile sector. In Sustainable Fibres and Textiles; Elsevier: Amsterdam, The Netherlands, 2017; pp. 323–346. [Google Scholar]
  29. Nawaz, M.S.; Ahsan, M. Comparison of physico-chemical, advanced oxidation and biological techniques for the textile wastewater treatment. Alex. Eng. J. 2014, 53, 717–722. [Google Scholar] [CrossRef] [Green Version]
  30. Dey, S.; Islam, A. A review on textile wastewater characterization in Bangladesh. Resour. Environ. 2015, 5, 15–44. [Google Scholar]
  31. Kant, R. Textile dyeing industry an environmental hazard. Nat. Sci. 2011, 4, 22–26. [Google Scholar] [CrossRef] [Green Version]
  32. Ghaly, A.; Ananthashankar, R.; Alhattab, M.; Ramakrishnan, V. Production, characterization and treatment of textile effluents: A critical review. J. Chem. Eng. Process Technol. 2014, 5, 1–19. [Google Scholar]
  33. Shehzadi, M.; Afzal, M.; Khan, M.U.; Islam, E.; Mobin, A.; Anwar, S.; Khan, Q.M. Enhanced degradation of textile effluent in constructed wetland system using Typha domingensis and textile effluent-degrading endophytic bacteria. Water Res. 2014, 58, 152–159. [Google Scholar] [CrossRef]
  34. Watharkar, A.D.; Khandare, R.V.; Waghmare, P.R.; Jagadale, A.D.; Govindwar, S.P.; Jadhav, J.P. Treatment of textile effluent in a developed phytoreactor with immobilized bacterial augmentation and subsequent toxicity studies on Etheostoma olmstedi fish. J. Hazard. Mater. 2015, 283, 698–704. [Google Scholar] [CrossRef]
  35. Tara, N.; Iqbal, M.; Mahmood Khan, Q.; Afzal, M. Bioaugmentation of floating treatment wetlands for the remediation of textile effluent. Water Environ. J. 2019, 33, 124–134. [Google Scholar] [CrossRef]
  36. Hussain, Z.; Arslan, M.; Malik, M.H.; Mohsin, M.; Iqbal, S.; Afzal, M. Integrated perspectives on the use of bacterial endophytes in horizontal flow constructed wetlands for the treatment of liquid textile effluent: Phytoremediation advances in the field. J. Environ. Manag. 2018, 224, 387–395. [Google Scholar] [CrossRef] [PubMed]
  37. Kadam, S.K.; Watharkar, A.D.; Chandanshive, V.V.; Khandare, R.V.; Jeon, B.-H.; Jadhav, J.P.; Govindwar, S.P. Co-planted floating phyto-bed along with microbial fuel cell for enhanced textile effluent treatment. J. Clean. Prod. 2018, 203, 788–798. [Google Scholar] [CrossRef]
  38. Tara, N.; Arslan, M.; Hussain, Z.; Iqbal, M.; Khan, Q.M.; Afzal, M. On-site performance of floating treatment wetland macrocosms augmented with dye-degrading bacteria for the remediation of textile industry wastewater. J. Clean. Prod. 2019, 217, 541–548. [Google Scholar] [CrossRef]
  39. Bafana, A.; Devi, S.S.; Chakrabarti, T. Azo dyes: Past, present and the future. Environ. Rev. 2011, 19, 350–371. [Google Scholar] [CrossRef]
  40. Essandoh, M.; Garcia, R.A. Efficient removal of dyes from aqueous solutions using a novel hemoglobin/iron oxide composite. Chemosphere 2018, 206, 502–512. [Google Scholar] [CrossRef]
  41. Uddin, M.G.; Islam, M.M.; Islam, M.R. Effects of reductive stripping of reactive dyes on the quality of cotton fabric. Fash. Text. 2015, 2, 8. [Google Scholar] [CrossRef] [Green Version]
  42. El Harfi, S.; El Harfi, A. Classifications, properties and applications of textile dyes: A review. Appl. J. Environ. Eng. Sci. 2017, 3, 311–320. [Google Scholar]
  43. Benkhaya, S.; El Harfi, A. A critical review of surface water contaminated with dyes from textile industry effluent: Possible approaches. Appl. J. Environ. Eng. Sci. 2018, 4, 1–12. [Google Scholar]
  44. Imran, M.; Shaharoona, B.; Crowley, D.E.; Khalid, A.; Hussain, S.; Arshad, M. The stability of textile azo dyes in soil and their impact on microbial phospholipid fatty acid profiles. Ecotoxicol. Environ. Saf. 2015, 120, 163–168. [Google Scholar] [CrossRef]
  45. Uday, U.S.P.; Mahata, N.; Sasmal, S.; Bandyopadhyay, T.K.; Mondal, A.; Bhunia, B. Dyes Contamination in the Environment: Ecotoxicological Effects, Health Hazards, and Biodegradation and Bioremediation Mechanisms for Environmental Cleanup. In Environmental Pollutants and Their Bioremediation Approaches; CRC Press: Boca Raton, FL, USA, 2017; pp. 127–176. [Google Scholar]
  46. Bokare, A.D.; Chikate, R.C.; Rode, C.V.; Paknikar, K.M. Iron-nickel bimetallic nanoparticles for reductive degradation of azo dye Orange G in aqueous solution. Appl. Catal. B-Environ. 2008, 79, 270–278. [Google Scholar] [CrossRef]
  47. Ismail, A.; Toriman, M.E.; Juahir, H.; Zain, S.M.; Habir, N.L.A.; Retnam, A.; Kamaruddin, M.K.A.; Umar, R.; Azid, A. Spatial assessment and source identification of heavy metals pollution in surface water using several chemometric techniques. Mar. Pollut. Bull. 2016, 106, 292–300. [Google Scholar] [CrossRef] [Green Version]
  48. Khatri, J.; Nidheesh, P.; Singh, T.A.; Kumar, M.S. Advanced oxidation processes based on zero-valent aluminium for treating textile wastewater. Chem. Eng. J. 2018, 348, 67–73. [Google Scholar] [CrossRef]
  49. Bhatia, D.; Sharma, N.R.; Kanwar, R.; Singh, J. Physicochemical assessment of industrial textile effluents of Punjab (India). Appl. Water Sci. 2018, 8, 83. [Google Scholar] [CrossRef] [Green Version]
  50. Maruthi, Y.; Rao, S.; Kiran, D. Evaluation of ground water pollution potential in Chandranagar, Visakhapatnam: A case study. J. Ecobiol. 2004, 16, 423–430. [Google Scholar]
  51. Mohabansi, N.P.; Tekade, P.; Bawankar, S. Physico-chemical and microbiological analysis of textile industry effluent of Wardha region. Water Res. Dev. 2011, 1, 40–44. [Google Scholar]
  52. Kolhe, A.; Pawar, V. Physico-chemical analysis of effluents from dairy industry. Rec. Res. Sci. Technol. 2011, 3, 29–32. [Google Scholar]
  53. Elango, G.; Govindasamy, R. Removal of Colour from Textile Dyeing Effluent Using Temple Waste Flowers as Ecofriendly Adsorbent. IOSR J. Appl. Chem. 2018, 11, 19–28. [Google Scholar]
  54. Bilotta, G.; Brazier, R. Understanding the influence of suspended solids on water quality and aquatic biota. Water Res. 2008, 42, 2849–2861. [Google Scholar] [CrossRef]
  55. Durotoye, T.O.; Adeyemi, A.A.; Omole, D.O.; Onakunle, O. Impact assessment of wastewater discharge from a textile industry in Lagos, Nigeria. Cogent Eng. 2018, 5, 1531687. [Google Scholar] [CrossRef]
  56. Ubale, M.A.; Salkar, V.D. Experimental study on electrocoagulation of textile wastewater by continuous horizontal flow through aluminum baffles. Korean J. Chem. Eng. 2017, 34, 1044–1050. [Google Scholar] [CrossRef]
  57. Ismail, M.; Akhtar, K.; Khan, M.; Kamal, T.; Khan, M.A.; M Asiri, A.; Seo, J.; Khan, S.B. Pollution, toxicity and carcinogenicity of organic dyes and their catalytic bio-remediation. Curr. Pharm. Des. 2019, 25, 3645–3663. [Google Scholar] [CrossRef] [PubMed]
  58. Sultana, T.; Arooj, F.; Nawaz, M.; Alam, S. Removal of Heavy Metals from Contaminated Soil using Plants: A Mini-Review. PSM Biol. Res. 2019, 4, 113–117. [Google Scholar]
  59. Yin, K.; Wang, Q.; Lv, M.; Chen, L. Microorganism remediation strategies towards heavy metals. Chem. Eng. J. 2019, 360, 1553–1563. [Google Scholar] [CrossRef]
  60. Rezaei, A.; Hassani, H.; Hassani, S.; Jabbari, N.; Mousavi, S.B.F.; Rezaei, S. Evaluation of groundwater quality and heavy metal pollution indices in Bazman basin, southeastern Iran. Groundw. Sustain. Dev. 2019, 9, 100245. [Google Scholar] [CrossRef]
  61. Roque, F.; Diaz, K.; Ancco, M.; Delgado, D.; Tejada, K. Biodepuration of domestic sewage, textile effluents and acid mine drainage using starch-based xerogel from recycled potato peels. Water Sci. Technol. 2018, 77, 1250–1261. [Google Scholar] [CrossRef]
  62. Järup, L. Hazards of heavy metal contamination. Br. Med. Bull. 2003, 68, 167–182. [Google Scholar] [CrossRef] [Green Version]
  63. Noreen, M.; Shahid, M.; Iqbal, M.; Nisar, J. Measurement of cytotoxicity and heavy metal load in drains water receiving textile effluents and drinking water in vicinity of drains. Measurement 2017, 109, 88–99. [Google Scholar] [CrossRef]
  64. Mulugeta, M.; Tibebe, D. Assessment of some selected metals from textile effluents in amhara region using AAS and ICPOES. Assessment 2019, 7, 27–31. [Google Scholar] [CrossRef]
  65. Wijeyaratne, W.D.N.; Wickramasinghe, P.M.U. Treated textile effluents: Cytotoxic and genotoxic effects in the natural aquatic environment. Bull. Environ. Contam. Toxicol. 2020, 104, 245–252. [Google Scholar] [CrossRef]
  66. Paździor, K.; Bilińska, L.; Ledakowicz, S. A review of the existing and emerging technologies in the combination of AOPs and biological processes in industrial textile wastewater treatment. Chem. Eng. J. 2019, 376, 120597. [Google Scholar] [CrossRef]
  67. Holkar, C.R.; Jadhav, A.J.; Pinjari, D.V.; Mahamuni, N.M.; Pandit, A.B. A critical review on textile wastewater treatments: Possible approaches. J. Environ. Manag. 2016, 182, 351–366. [Google Scholar] [CrossRef] [PubMed]
  68. Deng, D.; Aryal, N.; Ofori-Boadu, A.; Jha, M.K. Textiles wastewater treatment. Water Environ. Res 2018, 90, 1648–1662. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  69. Vandevivere, P.C.; Bianchi, R.; Verstraete, W. Treatment and reuse of wastewater from the textile wet-processing industry: Review of emerging technologies. J. Chem. Technol. Biotechnol. Int. Res. Process Environ. Clean Technol. 1998, 72, 289–302. [Google Scholar] [CrossRef]
  70. Rodrigues, C.S.; Madeira, L.M.; Boaventura, R.A. Synthetic textile wastewaters treatment by coagulation/flocculation using ferric salt as coagulant. Environ. Eng. Manag. J. 2017, 16, 1881–1889. [Google Scholar]
  71. Queiroz, R.D.C.S.D.; Lôbo, I.P.; de Ribeiro, V.S.; Rodrigues, L.B.; de Almeida Neto, J.A. Assessment of autochthonous aquatic macrophytes with phytoremediation potential for dairy wastewater treatment in floating constructed wetlands. Int. J. Phytorem. 2020, 22, 518–528. [Google Scholar] [CrossRef]
  72. Chandran, D. A review of the textile industries waste water treatment methodologies. Int. J. Sci. Eng. Res. 2016, 7, 2229–5518. [Google Scholar]
  73. Dąbrowski, A. Adsorption—From theory to practice. Adv. Colloid Interface Sci. 2001, 93, 135–224. [Google Scholar] [CrossRef]
  74. Amrial, M.; Kusumandari, K.; Saraswati, T.; Suselo, Y. Textile Wastewater Treatment by Using Plasma Corona Discharge in a Continuous Flow System; IOP Conference Series: Materials Science and Engineering, 2019; IOP Publishing: Bristol, UK, 2019; p. 012016. [Google Scholar]
  75. Paprowicz, J.; Słodczyk, S. Application of biologically activated sorptive columns for textile waste water treatment. Environ. Technol. 1988, 9, 271–280. [Google Scholar] [CrossRef]
  76. Choo, K.-H.; Choi, S.-J.; Hwang, E.-D. Effect of coagulant types on textile wastewater reclamation in a combined coagulation/ultrafiltration system. Desalination 2007, 202, 262–270. [Google Scholar] [CrossRef]
  77. Kalaiarasi, K.; Lavanya, A.; Amsamani, S.; Bagyalakshmi, G. Decolourization of textile dye effluent by non-viable biomass of Aspergillus fumigatus. Braz. Arc. Biol. Technol. 2012, 55, 471–476. [Google Scholar] [CrossRef]
  78. Forss, J.; Lindh, M.V.; Pinhassi, J.; Welander, U. Microbial biotreatment of actual textile wastewater in a continuous sequential rice husk biofilter and the microbial community involved. PLoS ONE 2017, 12, e0170562. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  79. Can, O.; Kobya, M.; Demirbas, E.; Bayramoglu, M. Treatment of the textile wastewater by combined electrocoagulation. Chemosphere 2006, 62, 181–187. [Google Scholar] [CrossRef]
  80. GilPavas, E.; Dobrosz-Gómez, I.; Gómez-García, M.-Á. Optimization and toxicity assessment of a combined electrocoagulation, H2O2/Fe2+/UV and activated carbon adsorption for textile wastewater treatment. Sci. Total Environ. 2019, 651, 551–560. [Google Scholar] [CrossRef] [PubMed]
  81. Aleem, M.; Cao, J.; Li, C.; Rashid, H.; Wu, Y.; Nawaz, M.I.; Abbas, M.; Akram, M.W. Coagulation-and Adsorption-Based Environmental Impact Assessment and Textile Effluent Treatment. Water Air Soil Pollut. 2020, 231, 45. [Google Scholar] [CrossRef]
  82. Bilińska, L.; Blus, K.; Gmurek, M.; Ledakowicz, S. Coupling of electrocoagulation and ozone treatment for textile wastewater reuse. Chem. Eng. J. 2019, 358, 992–1001. [Google Scholar] [CrossRef]
  83. Dotto, J.; Fagundes-Klen, M.R.; Veit, M.T.; Palácio, S.M.; Bergamasco, R. Performance of different coagulants in the coagulation/flocculation process of textile wastewater. J. Clean. Prod. 2019, 208, 656–665. [Google Scholar] [CrossRef]
  84. Khandegar, V.; Saroha, A.K. Electrocoagulation for the treatment of textile industry effluent–a review. J. Environ. Manag. 2013, 128, 949–963. [Google Scholar] [CrossRef]
  85. Beltrán-Heredia, J.; Sánchez-Martín, J.; Rodríguez-Sánchez, M. Textile wastewater purification through natural coagulants. Appl. Water Sci. 2011, 1, 25–33. [Google Scholar] [CrossRef] [Green Version]
  86. Abouri, M.; Souabi, S.; Jada, A. Optimization of Coagulation Flocculation Process for the Removal of Heavy Metals from Real Textile Wastewater. Adv. Intell. Syst. Sustain. Dev. (AI2SD’2018) Vol 3 Adv. Intell. Syst. Appl. Environ. 2019, 913, 257. [Google Scholar]
  87. Solano, A.M.S.; de Araújo, C.K.C.; de Melo, J.V.; Peralta-Hernandez, J.M.; da Silva, D.R.; Martínez-Huitle, C.A. Decontamination of real textile industrial effluent by strong oxidant species electrogenerated on diamond electrode: Viability and disadvantages of this electrochemical technology. Appl. Catal. B Environ. 2013, 130, 112–120. [Google Scholar] [CrossRef]
  88. Martínez-Huitle, C.A.; Panizza, M. Electrochemical oxidation of organic pollutants for wastewater treatment. Curr. Opin. Electrochem. 2018, 11, 62–71. [Google Scholar] [CrossRef]
  89. Marin, N.M.; Pascu, L.F.; Demba, A.; Nita-Lazar, M.; Badea, I.A.; Aboul-Enein, H. Removal of the Acid Orange 10 by ion exchange and microbiological methods. Int. J. Environ. Sci. Technol. 2019, 16, 6357–6366. [Google Scholar] [CrossRef]
  90. Yetim, T.; Tekin, T. A kinetic study on photocatalytic and sonophotocatalytic degradation of textile dyes. Period. Polytech. Chem. Eng. 2017, 61, 102–108. [Google Scholar] [CrossRef] [Green Version]
  91. Jorfi, S.; Barzegar, G.; Ahmadi, M.; Soltani, R.D.C.; Takdastan, A.; Saeedi, R.; Abtahi, M. Enhanced coagulation-photocatalytic treatment of Acid red 73 dye and real textile wastewater using UVA/synthesized MgO nanoparticles. J. Environ. Manag. 2016, 177, 111–118. [Google Scholar] [CrossRef]
  92. Naseem, Z.; Bhatti, H.N.; Iqbal, M.; Noreen, S.; Zahid, M. Fenton and photo-fenton oxidation for the remediation of textile effluents: An experimental study. Text. Cloth. 2019, 235–251. [Google Scholar] [CrossRef]
  93. Sharma, A.; Syed, Z.; Brighu, U.; Gupta, A.B.; Ram, C. Adsorption of textile wastewater on alkali-activated sand. J. Clean. Prod. 2019, 220, 23–32. [Google Scholar] [CrossRef]
  94. Dasgupta, J.; Sikder, J.; Chakraborty, S.; Curcio, S.; Drioli, E. Remediation of textile effluents by membrane based treatment techniques: A state of the art review. J. Environ. Manag. 2015, 147, 55–72. [Google Scholar] [CrossRef] [PubMed]
  95. Liang, Y.; Zhu, H.; Bañuelos, G.; Yan, B.; Zhou, Q.; Yu, X.; Cheng, X. Constructed wetlands for saline wastewater treatment: A review. Ecol. Eng. 2017, 98, 275–285. [Google Scholar] [CrossRef]
  96. Shi, L.; Huang, J.; Zeng, G.; Zhu, L.; Gu, Y.; Shi, Y.; Yi, K.; Li, X. Roles of surfactants in pressure-driven membrane separation processes: A review. Environ. Sci. Pollut. Res. 2019, 26, 30731–30754. [Google Scholar] [CrossRef]
  97. Van der Bruggen, B.; Canbolat, Ç.B.; Lin, J.; Luis, P. The potential of membrane technology for treatment of textile wastewater. In Sustainable Membrane Technology for Water and Wastewater Treatment; Springer: Berlin/Heidelberg, Germany, 2017; pp. 349–380. [Google Scholar]
  98. Saeed, T.; Khan, T. Constructed wetlands for industrial wastewater treatment: Alternative media, input biodegradation ratio and unstable loading. J. Environ. Chem. Eng. 2019, 7, 103042. [Google Scholar] [CrossRef]
  99. Periasamy, D.; Mani, S.; Ambikapathi, R. White Rot Fungi and Their Enzymes for the Treatment of Industrial Dye Effluents. In Recent Advancement in White Biotechnology Through Fungi; Springer: Berlin/Heidelberg, Germany, 2019; pp. 73–100. [Google Scholar]
  100. Anastasi, A.; Spina, F.; Prigione, V.; Tigini, V.; Giansanti, P.; Varese, G.C. Scale-up of a bioprocess for textile wastewater treatment using Bjerkandera adusta. Bioresour. Technol. 2010, 101, 3067–3075. [Google Scholar] [CrossRef] [PubMed]
  101. Fazal, T.; Mushtaq, A.; Rehman, F.; Khan, A.U.; Rashid, N.; Farooq, W.; Rehman, M.S.U.; Xu, J. Bioremediation of textile wastewater and successive biodiesel production using microalgae. Renew. Sust. Energ. Rev. 2018, 82, 3107–3126. [Google Scholar] [CrossRef]
  102. Sekomo, C.B.; Kagisha, V.; Rousseau, D.; Lens, P. Heavy metal removal by combining anaerobic upflow packed bed reactors with water hyacinth ponds. Environ. Technol. 2012, 33, 1455–1464. [Google Scholar] [CrossRef]
  103. Yaseen, D.A.; Scholz, M. Treatment of synthetic textile wastewater containing dye mixtures with microcosms. Environ. Sci. Pollut. Rese. 2018, 25, 1980–1997. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  104. Siddique, K.; Rizwan, M.; Shahid, M.J.; Ali, S.; Ahmad, R.; Rizvi, H. Textile wastewater treatment options: A critical review. In Enhancing Cleanup of Environmental Pollutants; Springer: Berlin/Heidelberg, Germany, 2017; pp. 183–207. [Google Scholar]
  105. Simsek, H.; Kasi, M.; Ohm, J.-B.; Blonigen, M.; Khan, E. Bioavailable and biodegradable dissolved organic nitrogen in activated sludge and trickling filter wastewater treatment plants. Water Res. 2013, 47, 3201–3210. [Google Scholar] [CrossRef] [PubMed]
  106. Singh, R.P.; Singh, P.K.; Gupta, R.; Singh, R.L. Treatment and recycling of wastewater from textile industry. In Advances in Biological Treatment of Industrial Waste Water and their Recycling for a Sustainable Future; Springer: Berlin/Heidelberg, Germany, 2019; pp. 225–266. [Google Scholar]
  107. Winanti, E.; Rahmadyanti, E.; Fajarwati, I. Ecological Approach of Campus Wastewater Treatment Using Constructed Wetland; IOP Conference Series: Materials Science and Engineering, 2018; IOP Publishing: Bristol, UK, 2018; p. 012062. [Google Scholar]
  108. Afzal, M.; Rehman, K.; Shabir, G.; Tahseen, R.; Ijaz, A.; Hashmat, A.J.; Brix, H. Large-scale remediation of oil-contaminated water using floating treatment wetlands. NPJ Clean Water 2019, 2, 1–10. [Google Scholar] [CrossRef]
  109. El-Esawi, M.A.; Alaraidh, I.A.; Alsahli, A.A.; Alzahrani, S.M.; Ali, H.M.; Alayafi, A.A.; Ahmad, M. Serratia liquefaciens KM4 Improves Salt Stress Tolerance in Maize by Regulating Redox Potential, Ion Homeostasis, Leaf Gas Exchange and Stress-Related Gene Expression. Int. J. Mol. Sci. 2018, 19, 3310. [Google Scholar] [CrossRef] [Green Version]
  110. El-Esawi, M.A.; Al-Ghamdi, A.A.; Ali, H.M.; Alayafi, A.A. Azospirillum lipoferum FK1 confers improved salt tolerance in chickpea (Cicer arietinum L.) by modulating osmolytes, antioxidant machinery and stress-related genes expression. Environ. Exp. Bot. 2019, 159, 55–65. [Google Scholar] [CrossRef]
  111. Borne, K.E.; Fassman, E.A.; Tanner, C.C. Floating treatment wetland retrofit to improve stormwater pond performance for suspended solids, copper and zinc. Ecol. Eng. 2013, 54, 173–182. [Google Scholar] [CrossRef]
  112. Ijaz, A.; Shabir, G.; Khan, Q.M.; Afzal, M. Enhanced remediation of sewage effluent by endophyte-assisted floating treatment wetlands. Ecol. Eng. 2015, 84, 58–66. [Google Scholar] [CrossRef]
  113. Yeh, N.; Yeh, P.; Chang, Y.-H. Artificial floating islands for environmental improvement. Renew Sustain Energy Rev. 2015, 47, 616–622. [Google Scholar] [CrossRef]
  114. El-Esawi, M.A. Genetic diversity and evolution of Brassica genetic resources: From morphology to novel genomic technologies—A review. Plant Genet. Resour. 2017, 15, 388–399. [Google Scholar] [CrossRef]
  115. El-Esawi, M.A.; Germaine, K.; Bourke, P.; Malone, R. AFLP analysis of genetic diversity and phylogenetic relationships of Brassica oleracea in Ireland. Comptes Rendus Biol. 2016, 339, 163–170. [Google Scholar] [CrossRef]
  116. Tanner, C.C.; Headley, T.R. Components of floating emergent macrophyte treatment wetlands influencing removal of stormwater pollutants. Ecol. Eng. 2011, 37, 474–486. [Google Scholar] [CrossRef]
  117. Zhang, L.; Zhao, J.; Cui, N.; Dai, Y.; Kong, L.; Wu, J.; Cheng, S. Enhancing the water purification efficiency of a floating treatment wetland using a biofilm carrier. Environ. Sci. Pollut. Rese. 2016, 23, 7437–7443. [Google Scholar] [CrossRef] [PubMed]
  118. Borne, K.E.; Fassman-Beck, E.A.; Winston, R.J.; Hunt, W.F.; Tanner, C.C. Implementation and maintenance of floating treatment wetlands for urban stormwater management. J. Environ. Eng. 2015, 141, 04015030. [Google Scholar] [CrossRef]
  119. Ali, S.; Abbas, Z.; Rizwan, M.; Zaheer, I.E.; Yavaş, İ.; Ünay, A.; Abdel-Daim, M.M.; Bin-Jumah, M.; Hasanuzzaman, M.; Kalderis, D. Application of Floating Aquatic Plants in Phytoremediation of Heavy Metals Polluted Water: A Review. Sustainability 2020, 12, 1927. [Google Scholar] [CrossRef] [Green Version]
  120. Chang, N.-B.; Xuan, Z.; Marimon, Z.; Islam, K.; Wanielista, M.P. Exploring hydrobiogeochemical processes of floating treatment wetlands in a subtropical stormwater wet detention pond. Ecol. Eng. 2013, 54, 66–76. [Google Scholar] [CrossRef]
  121. Wand, H.; Vacca, G.; Kuschk, P.; Krüger, M.; Kästner, M. Removal of bacteria by filtration in planted and non-planted sand columns. Water Res. 2007, 41, 159–167. [Google Scholar] [CrossRef] [PubMed]
  122. Vymazal, J. Constructed wetlands for treatment of industrial wastewaters: A review. Ecol. Eng. 2014, 73, 724–751. [Google Scholar] [CrossRef]
  123. Shahid, M.J.; Ali, S.; Shabir, G.; Siddique, M.; Rizwan, M.; Seleiman, M.F.; Afzal, M. Comparing the performance of four macrophytes in bacterial assisted floating treatment wetlands for the removal of trace metals (Fe, Mn, Ni, Pb, and Cr) from polluted river water. Chemosphere 2020, 243, 125353. [Google Scholar] [CrossRef] [PubMed]
  124. Nawaz, N.; Ali, S.; Shabir, G.; Rizwan, M.; Shakoor, M.B.; Shahid, M.J.; Afzal, M.; Arslan, M.; Hashem, A.; Abd_Allah, E.F. Bacterial Augmented Floating Treatment Wetlands for Efficient Treatment of Synthetic Textile Dye Wastewater. Sustainability 2020, 12, 3731. [Google Scholar] [CrossRef]
  125. Borne, K.E. Floating treatment wetland influences on the fate and removal performance of phosphorus in stormwater retention ponds. Ecol. Eng. 2014, 69, 76–82. [Google Scholar] [CrossRef]
  126. Ashraf, S.; Afzal, M.; Naveed, M.; Shahid, M.; Ahmad Zahir, Z. Endophytic bacteria enhance remediation of tannery effluent in constructed wetlands vegetated with Leptochloa fusca. Int. J. Phytorem. 2018, 20, 121–128. [Google Scholar] [CrossRef]
  127. Shahid, M.; Arslan, M.; Ali, S.; Siddique, M.; Afzal, M. Floating wetlands: A sustainable tool for wastewater treatment. CLEAN Soil Air Water 2018, 46, 1–13. [Google Scholar] [CrossRef]
  128. Zhu, L.; Li, Z.; Ketola, T. Biomass accumulations and nutrient uptake of plants cultivated on artificial floating beds in China’s rural area. Ecol. Eng. 2011, 37, 1460–1466. [Google Scholar] [CrossRef]
  129. Khin, T.; Annachhatre, A.P. Novel microbial nitrogen removal processes. Biotechnol. Adv. 2004, 22, 519–532. [Google Scholar] [CrossRef]
  130. Borne, K.E.; Fassman-Beck, E.A.; Tanner, C.C. Floating treatment wetland influences on the fate of metals in road runoff retention ponds. Water Res. 2014, 48, 430–442. [Google Scholar] [CrossRef] [PubMed]
  131. Zhang, M.; Qiao, S.; Shao, D.; Jin, R.; Zhou, J. Simultaneous nitrogen and phosphorus removal by combined anammox and denitrifying phosphorus removal process. J. Chem. Technol. Biotechnol. 2018, 93, 94–104. [Google Scholar] [CrossRef]
  132. Shahid, M.J.; Tahseen, R.; Siddique, M.; Ali, S.; Iqbal, S.; Afzal, M. Remediation of polluted river water by floating treatment wetlands. Water Supply 2019, 19, 967–977. [Google Scholar] [CrossRef]
  133. Chua, L.H.; Tan, S.B.; Sim, C.; Goyal, M.K. Treatment of baseflow from an urban catchment by a floating wetland system. Ecol. Eng. 2012, 49, 170–180. [Google Scholar] [CrossRef]
  134. Nakphet, S.; Ritchie, R.J.; Kiriratnikom, S. Aquatic plants for bioremediation in red hybrid tilapia (Oreochromis niloticus× Oreochromis mossambicus) recirculating aquaculture. Aquacult. Int. 2017, 25, 619–633. [Google Scholar] [CrossRef]
  135. Chaturvedi, H.; Singh, V.; Gupta, G. Potential of bacterial endophytes as plant growth promoting factors. J. Plant Pathol. Microbiol. 2016, 7, 1–6. [Google Scholar] [CrossRef] [Green Version]
  136. Arslan, M.; Imran, A.; Khan, Q.M.; Afzal, M. Plant–bacteria partnerships for the remediation of persistent organic pollutants. Environ. Sci. Pollut. Res. 2017, 24, 4322–4336. [Google Scholar] [CrossRef] [PubMed]
  137. Fatima, K.; Afzal, M.; Imran, A.; Khan, Q.M. Bacterial rhizosphere and endosphere populations associated with grasses and trees to be used for phytoremediation of crude oil contaminated soil. Bull. Environ. Contam. Toxicol. 2015, 94, 314–320. [Google Scholar] [CrossRef]
  138. Shehzadi, M.; Fatima, K.; Imran, A.; Mirza, M.; Khan, Q.; Afzal, M. Ecology of bacterial endophytes associated with wetland plants growing in textile effluent for pollutant-degradation and plant growth-promotion potentials. Plant Biosyst. 2016, 150, 1261–1270. [Google Scholar] [CrossRef]
  139. Rehman, K.; Imran, A.; Amin, I.; Afzal, M. Inoculation with bacteria in floating treatment wetlands positively modulates the phytoremediation of oil field wastewater. J. Hazard. Mater. 2018, 349, 242–251. [Google Scholar] [CrossRef]
  140. Branda, S.S.; Vik, Å.; Friedman, L.; Kolter, R. Biofilms: The matrix revisited. Trends Microbiol. 2005, 13, 20–26. [Google Scholar] [CrossRef] [PubMed]
  141. Singh, S.; Singh, S.K.; Chowdhury, I.; Singh, R. Understanding the mechanism of bacterial biofilms resistance to antimicrobial agents. Open Microbiol. J. 2017, 11, 53–62. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  142. Urakawa, H.; Dettmar, D.L.; Thomas, S. The uniqueness and biogeochemical cycling of plant root microbial communities in a floating treatment wetland. Ecol. Eng. 2017, 108, 573–580. [Google Scholar] [CrossRef]
  143. Sun, Z.; Xie, D.; Jiang, X.; Fu, G.; Xiao, D.; Zheng, L. Effect of eco-remediation and microbial community using multilayer solar planted floating island (MS-PFI) in the drainage channel. BioRxiv 2018, 327965. [Google Scholar] [CrossRef]
  144. Achá, D.; Iniguez, V.; Roulet, M.; Guimaraes, J.R.D.; Luna, R.; Alanoca, L.; Sanchez, S. Sulfate-reducing bacteria in floating macrophyte rhizospheres from an Amazonian floodplain lake in Bolivia and their association with Hg methylation. Appl. Environ. Microbiol. 2005, 71, 7531–7535. [Google Scholar] [CrossRef] [Green Version]
  145. Lamers, L.P.; Van Diggelen, J.M.; Op Den Camp, H.J.; Visser, E.J.; Lucassen, E.C.; Vile, M.A.; Jetten, M.S.; Smolders, A.J.; Roelofs, J.G. Microbial transformations of nitrogen, sulfur, and iron dictate vegetation composition in wetlands: A review. Front. Microbiol. 2012, 3, 156. [Google Scholar] [CrossRef] [Green Version]
  146. Shahid, M.J.; Arslan, M.; Siddique, M.; Ali, S.; Tahseen, R.; Afzal, M. Potentialities of floating wetlands for the treatment of polluted water of river Ravi, Pakistan. Ecol. Eng. 2019, 133, 167–176. [Google Scholar] [CrossRef]
  147. Zhao, T.; Fan, P.; Yao, L.; Yan, G.; Li, D.; Zhang, W. Ammonifying bacteria in plant floating island of constructed wetland for strengthening decomposition of organic nitrogen. Trans. Chin. Soc. Agric. Eng. 2011, 27, 223–226. [Google Scholar]
  148. Govarthanan, M.; Mythili, R.; Selvankumar, T.; Kamala-Kannan, S.; Rajasekar, A.; Chang, Y.-C. Bioremediation of heavy metals using an endophytic bacterium Paenibacillus sp. RM isolated from the roots of Tridax procumbens. 3 Biotech 2016, 6, 242. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  149. Barathi, S.; Karthik, C.; Nadanasabapathi, S.; Padikasan, I.A. Biodegradation of textile dye Reactive Blue 160 by Bacillus firmus (Bacillaceae: Bacillales) and non-target toxicity screening of their degraded products. Toxicol. Rep. 2020, 7, 16–22. [Google Scholar] [CrossRef]
  150. Franca, R.D.G.; Vieira, A.; Carvalho, G.; Oehmen, A.; Pinheiro, H.M.; Crespo, M.T.B.; Lourenço, N.D. Oerskovia paurometabola can efficiently decolorize azo dye Acid Red 14 and remove its recalcitrant metabolite. Ecotoxicol. Environ. Saf. 2020, 191, 110007. [Google Scholar] [CrossRef] [PubMed]
  151. Garg, N.; Garg, A.; Mukherji, S. Eco-friendly decolorization and degradation of reactive yellow 145 textile dye by Pseudomonas aeruginosa and Thiosphaera pantotropha. J. Environ. Manag. 2020, 263, 110383. [Google Scholar] [CrossRef] [PubMed]
  152. Roy, D.C.; Biswas, S.K.; Saha, A.K.; Sikdar, B.; Rahman, M.; Roy, A.K.; Prodhan, Z.H.; Tang, S.-S. Biodegradation of Crystal Violet dye by bacteria isolated from textile industry effluents. PeerJ 2018, 6, e5015. [Google Scholar] [CrossRef]
  153. Najme, R.; Hussain, S.; Maqbool, Z.; Imran, M.; Mahmood, F.; Manzoor, H.; Yasmeen, T.; Shehzad, T. Biodecolorization of Reactive Yellow-2 by Serratia sp. RN34 Isolated from textile wastewater. Water Environ. Res. 2015, 87, 2065–2075. [Google Scholar] [CrossRef]
  154. Bheemaraddi, M.C.; Patil, S.; Shivannavar, C.T.; Gaddad, S.M. Isolation and characterization of Paracoccus sp. GSM2 capable of degrading textile azo dye reactive violet 5. Sci. World J. 2014, 2014, 410704. [Google Scholar] [CrossRef] [Green Version]
  155. Singh, R.P.; Singh, P.K.; Singh, R.L. Bacterial decolorization of textile azo dye acid orange by Staphylococcus hominis RMLRT03. Toxicol. Int. 2014, 21, 160. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  156. Garg, S.K.; Tripathi, M. Process parameters for decolorization and biodegradation of orange II (Acid Orange 7) in dye-simulated minimal salt medium and subsequent textile effluent treatment by Bacillus cereus (MTCC 9777) RMLAU1. Environ. Monit. Assess. 2013, 185, 8909–8923. [Google Scholar] [CrossRef]
  157. Lim, C.K.; Bay, H.H.; Aris, A.; Majid, Z.A.; Ibrahim, Z. Biosorption and biodegradation of Acid Orange 7 by Enterococcus faecalis strain ZL: Optimization by response surface methodological approach. Environ. Sci. Pollut. Res. 2013, 20, 5056–5066. [Google Scholar] [CrossRef]
  158. Surwase, S.V.; Deshpande, K.K.; Phugare, S.S.; Jadhav, J.P. Biotransformation studies of textile dye Remazol Orange 3R. 3 Biotech 2013, 3, 267–275. [Google Scholar] [CrossRef] [Green Version]
  159. Deive, F.; Domínguez, A.; Barrio, T.; Moscoso, F.; Morán, P.; Longo, M.; Sanromán, M. Decolorization of dye Reactive Black 5 by newly isolated thermophilic microorganisms from geothermal sites in Galicia (Spain). J. Hazard. Mater. 2010, 182, 735–742. [Google Scholar] [CrossRef]
  160. Wang, H.; Su, J.Q.; Zheng, X.W.; Tian, Y.; Xiong, X.J.; Zheng, T.L. Bacterial decolorization and degradation of the reactive dye Reactive Red 180 by Citrobacter sp. CK3. Int. Biodeterior. Biodegrad. 2009, 63, 395–399. [Google Scholar] [CrossRef]
  161. Kolekar, Y.M.; Pawar, S.P.; Gawai, K.R.; Lokhande, P.D.; Shouche, Y.S.; Kodam, K.M. Decolorization and degradation of Disperse Blue 79 and Acid Orange 10, by Bacillus fusiformis KMK5 isolated from the textile dye contaminated soil. Bioresour. Technol. 2008, 99, 8999–9003. [Google Scholar] [CrossRef] [PubMed]
  162. Kalyani, D.C.; Patil, P.S.; Jadhav, J.P.; Govindwar, S.P. Biodegradation of reactive textile dye Red BLI by an isolated bacterium Pseudomonas sp. SUK1. Bioresour. Technol. 2008, 99, 4635–4641. [Google Scholar] [CrossRef] [PubMed]
  163. Alhassani, H.A.; Rauf, M.A.; Ashraf, S.S. Efficient microbial degradation of Toluidine Blue dye by Brevibacillus sp. Dyes Pigments 2007, 75, 395–400. [Google Scholar] [CrossRef]
  164. Coughlin, M.F.; Kinkle, B.K.; Bishop, P.L. High performance degradation of azo dye Acid Orange 7 and sulfanilic acid in a laboratory scale reactor after seeding with cultured bacterial strains. Water Res. 2003, 37, 2757–2763. [Google Scholar] [CrossRef]
  165. Hu, T. Degradation of azo dye RP2B by Pseudomonas luteola. Water Sci. Technol. 1998, 38, 299–306. [Google Scholar] [CrossRef]
  166. Elango, G.; Rathika, G.; Elango, S. Physico-chemical parameters of textile dyeing effluent and its impacts with case study. Int. J. Res Chem. Environ. 2017, 7, 17–24. [Google Scholar]
  167. Mirbolooki, H.; Amirnezhad, R.; Pendashteh, A.R. Treatment of high saline textile wastewater by activated sludge microorganisms. J. Appl Res. Technol. 2017, 15, 167–172. [Google Scholar] [CrossRef]
  168. Hawes, M.C.; McLain, J.; Ramirez-Andreotta, M.; Curlango-Rivera, G.; Flores-Lara, Y.; Brigham, L.A. Extracellular trapping of soil contaminants by root border cells: New insights into plant defense. Agronomy 2016, 6, 5. [Google Scholar] [CrossRef]
  169. Cao, W.; Zhang, H.; Wang, Y.; Pan, J. Bioremediation of polluted surface water by using biofilms on filamentous bamboo. Ecol. Eng. 2012, 42, 146–149. [Google Scholar] [CrossRef]
  170. Prajapati, M.; van Bruggen, J.J.; Dalu, T.; Malla, R. Assessing the effectiveness of pollutant removal by macrophytes in a floating wetland for wastewater treatment. Appl Water Sci. 2017, 7, 4801–4809. [Google Scholar] [CrossRef] [Green Version]
  171. Chen, Z.; Cuervo, D.P.; Müller, J.A.; Wiessner, A.; Köser, H.; Vymazal, J.; Kästner, M.; Kuschk, P. Hydroponic root mats for wastewater treatment—A review. Environ. Sci. Pollut. Res. 2016, 23, 15911–15928. [Google Scholar] [CrossRef]
  172. Ijaz, A.; Iqbal, Z.; Afzal, M. Remediation of sewage and industrial effluent using bacterially assisted floating treatment wetlands vegetated with Typha domingensis. Water Sci. Technol. 2016, 74, 2192–2201. [Google Scholar] [CrossRef] [Green Version]
  173. Qamar, M.T.; Mumtaz, H.M.; Mohsin, M.; Asghar, H.N.; Iqbal, M.; Nasir, M. Development of floating treatment wetlands with plant-bacteria partnership to clean textile bleaching effluent. Ind. Text. 2019, 70, 502–511. [Google Scholar] [CrossRef]
  174. Kumar, S.; Pratap, B.; Dubey, D.; Dutta, V. Microbial Communities in Constructed Wetland Microcosms and Their Role in Treatment of Domestic Wastewater. In Emerging Eco-Friendly Green Technologies for Wastewater Treatment; Springer: Berlin/Heidelberg, Germany, 2020; pp. 311–327. [Google Scholar]
  175. Rehman, K.; Imran, A.; Amin, I.; Afzal, M. Enhancement of oil field-produced wastewater remediation by bacterially-augmented floating treatment wetlands. Chemosphere 2019, 217, 576–583. [Google Scholar] [CrossRef]
  176. Suryawan, I.; Helmy, Q.; Notodarmojo, S. Textile Wastewater Treatment: Colour and COD Removal of Reactive Black-5 by Ozonation; IOP Conference Series: Earth and Environmental Science, 2018; IOP Publishing: Bristol, UK, 2018; p. 012102. [Google Scholar]
  177. Mohan, S.; Vidhya, K.; Sivakumar, C.; Sugnathi, M.; Shanmugavadivu, V.; Devi, M. Textile Waste Water Treatment by Using Natural Coagulant (Neem-Azadirachta India). Int. Res. J. Multidis. Technovation 2019, 1, 636–642. [Google Scholar]
  178. Sathya, U.; Nithya, M.; Balasubramanian, N. Evaluation of advanced oxidation processes (AOPs) integrated membrane bioreactor (MBR) for the real textile wastewater treatment. J. Environ. Manag. 2019, 246, 768–775. [Google Scholar] [CrossRef]
  179. Tusief, M.Q.; Malik, M.H.; Asghar, H.N.; Mohsin, M.; Mahmood, N. Bioremediation of textile wastewater through floating treatment wetland system. Int. J. Agric. Biol. 2019, 22, 821–826. [Google Scholar]
  180. Darajeh, N.; Idris, A.; Masoumi, H.R.F.; Nourani, A.; Truong, P.; Sairi, N.A. Modeling BOD and COD removal from Palm Oil Mill Secondary Effluent in floating wetland by Chrysopogon zizanioides (L.) using response surface methodology. J. Environ. Manag. 2016, 181, 343–352. [Google Scholar] [CrossRef] [PubMed]
  181. Klomjek, P.; Nitisoravut, S. Constructed treatment wetland: A study of eight plant species under saline conditions. Chemosphere 2005, 58, 585–593. [Google Scholar] [CrossRef] [PubMed]
  182. Yulistyorini, A.; Puspasari, A.K.; Sari, A.A. Removal of BOD and TSS of Student Dormitory Greywater Using Vertical Sub-Surface Flow Constructed Wetland of Ipomoea Aquatica; IOP Conference Series: Materials Science and Engineering, 2019; IOP Publishing: Bristol, UK, 2019; p. 012056. [Google Scholar]
  183. Saeed, T.; Haque, I.; Khan, T. Organic matter and nutrients removal in hybrid constructed wetlands: Influence of saturation. Chem. Eng. J. 2019, 371, 154–165. [Google Scholar] [CrossRef]
  184. Vymazal, J. Removal of nutrients in various types of constructed wetlands. Sci. Total Environ. 2007, 380, 48–65. [Google Scholar] [CrossRef] [PubMed]
  185. Arivoli, A.; Sathiamoorthi, T.; Satheeshkumar, M. Treatment of Textile Effluent by Phytoremediation with the Aquatic Plants: Alternanthera sessilis. In Bioremediation and Sustainable Technologies for Cleaner Environment; Springer: Berlin/Heidelberg, Germany, 2017; pp. 185–197. [Google Scholar]
  186. Ladislas, S.; Gerente, C.; Chazarenc, F.; Brisson, J.; Andres, Y. Floating treatment wetlands for heavy metal removal in highway stormwater ponds. Ecol. Eng. 2015, 80, 85–91. [Google Scholar] [CrossRef]
  187. Ladislas, S.; El-Mufleh, A.; Gérente, C.; Chazarenc, F.; Andrès, Y.; Béchet, B. Potential of aquatic macrophytes as bioindicators of heavy metal pollution in urban stormwater runoff. Water Air Soil Pollut. 2012, 223, 877–888. [Google Scholar] [CrossRef]
  188. Gadd, G.M. Metals, minerals and microbes: Geomicrobiology and bioremediation. Microbiol. 2010, 156, 609–643. [Google Scholar] [CrossRef] [PubMed]
  189. Haq, S.; Bhatti, A.A.; Dar, Z.A.; Bhat, S.A. Phytoremediation of Heavy Metals: An Eco-Friendly and Sustainable Approach. In Bioremediation and Biotechnology; Springer: Berlin/Heidelberg, Germany, 2020; pp. 215–231. [Google Scholar]
  190. Ullah, A.; Heng, S.; Munis, M.F.H.; Fahad, S.; Yang, X. Phytoremediation of heavy metals assisted by plant growth promoting (PGP) bacteria: A review. Environ. Exp. Bot. 2015, 117, 28–40. [Google Scholar] [CrossRef]
  191. Hussain, I.; Aleti, G.; Naidu, R.; Puschenreiter, M.; Mahmood, Q.; Rahman, M.M.; Wang, F.; Shaheen, S.; Syed, J.H.; Reichenauer, T.G. Microbe and plant assisted-remediation of organic xenobiotics and its enhancement by genetically modified organisms and recombinant technology: A review. Sci. Total Environ. 2018, 628, 1582–1599. [Google Scholar] [CrossRef]
  192. Doty, S.L. Enhancing phytoremediation through the use of transgenics and endophytes. New Phytol. 2008, 179, 318–333. [Google Scholar] [CrossRef]
  193. Wang, C.-Y.; Sample, D.J.; Bell, C. Vegetation effects on floating treatment wetland nutrient removal and harvesting strategies in urban stormwater ponds. Sci. Total Environ. 2014, 499, 384–393. [Google Scholar] [CrossRef]
  194. Headley, T.; Tanner, C. Constructed wetlands with floating emergent macrophytes: An innovative stormwater treatment technology. Crit. Rev. Environ. Sci. Technol. 2012, 42, 2261–2310. [Google Scholar] [CrossRef]
  195. Correa-García, S.; Pande, P.; Séguin, A.; St-Arnaud, M.; Yergeau, E. Rhizoremediation of petroleum hydrocarbons: A model system for plant microbiome manipulation. Microb. Biotechnol. 2018, 11, 819–832. [Google Scholar] [CrossRef] [PubMed]
  196. Yergeau, E.; Tremblay, J.; Joly, S.; Labrecque, M.; Maynard, C.; Pitre, F.E.; St-Arnaud, M.; Greer, C.W. Soil contamination alters the willow root and rhizosphere metatranscriptome and the root–rhizosphere interactome. ISME J. 2018, 12, 869–884. [Google Scholar] [CrossRef] [Green Version]
  197. Sheoran, A. A laboratory treatment study of acid mine water of wetlands with emergent macrophyte (Typha angustata). Int. J. Min. Reclam. Environ. 2006, 20, 209–222. [Google Scholar] [CrossRef]
  198. Kumar, K.; Kumar, D.; Teja, V.; Venkateswarlu, V.; Kumar, M.; Nadendla, R. A review on Typha angustata. Int. J. Phytopharm. 2013, 4, 277–281. [Google Scholar]
  199. Vymazal, J. Plants used in constructed wetlands with horizontal subsurface flow: A review. Hydrobiologia 2011, 674, 133–156. [Google Scholar] [CrossRef]
  200. Vymazal, J. The use of hybrid constructed wetlands for wastewater treatment with special attention to nitrogen removal: A review of a recent development. Water Res. 2013, 47, 4795–4811. [Google Scholar] [CrossRef] [PubMed]
  201. Rezania, S.; Taib, S.M.; Din, M.F.M.; Dahalan, F.A.; Kamyab, H. Comprehensive review on phytotechnology: Heavy metals removal by diverse aquatic plants species from wastewater. J. Hazard. Mater. 2016, 318, 587–599. [Google Scholar] [CrossRef] [PubMed]
  202. Valipour, A.; Ahn, Y.-H. Constructed wetlands as sustainable ecotechnologies in decentralization practices: A review. Environ. Sci. Pollut. Res. 2016, 23, 180–197. [Google Scholar] [CrossRef]
  203. Fritioff, Å.; Greger, M. Aquatic and terrestrial plant species with potential to remove heavy metals from stormwater. Int. J. Phytorem. 2003, 5, 211–224. [Google Scholar] [CrossRef]
  204. Vymazal, J. Emergent plants used in free water surface constructed wetlands: A review. Ecol. Eng. 2013, 61, 582–592. [Google Scholar] [CrossRef]
  205. Di Luca, G.A.; Mufarrege, M.; Hadad, H.R.; Maine, M.A. Nitrogen and phosphorus removal and Typha domingensis tolerance in a floating treatment wetland. Sci. Total Environ. 2019, 650, 233–240. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  206. Nichols, P.; Lucke, T.; Drapper, D.; Walker, C. Performance evaluation of a floating treatment wetland in an urban catchment. Water 2016, 8, 244. [Google Scholar] [CrossRef] [Green Version]
  207. Gao, L.; Zhou, W.; Huang, J.; He, S.; Yan, Y.; Zhu, W.; Wu, S.; Zhang, X. Nitrogen removal by the enhanced floating treatment wetlands from the secondary effluent. Bioresour. Technol. 2017, 234, 243–252. [Google Scholar] [CrossRef]
  208. Song, H.-L.; Li, X.-N.; Lu, X.-W.; Inamori, Y. Investigation of microcystin removal from eutrophic surface water by aquatic vegetable bed. Ecol. Eng. 2009, 35, 1589–1598. [Google Scholar] [CrossRef]
  209. Tambunan, J.A.M.; Effendi, H.; Krisanti, M. Phytoremediating Batik Wastewater Using Vetiver Chrysopogon zizanioides (L). Pol. J. Environ. Stud. 2018, 27, 1281–1288. [Google Scholar] [CrossRef]
  210. De Stefani, G.; Tocchetto, D.; Salvato, M.; Borin, M. Performance of a floating treatment wetland for in-stream water amelioration in NE Italy. Hydrobiologia 2011, 674, 157–167. [Google Scholar] [CrossRef]
  211. Park, J.B.; Sukias, J.P.; Tanner, C.C. Floating treatment wetlands supplemented with aeration and biofilm attachment surfaces for efficient domestic wastewater treatment. Ecol. Eng. 2019, 139, 105582. [Google Scholar] [CrossRef]
  212. Fahid, M.; Arslan, M.; Shabir, G.; Younus, S.; Yasmeen, T.; Rizwan, M.; Siddique, K.; Ahmad, S.R.; Tahseen, R.; Iqbal, S. Phragmites australis in combination with hydrocarbons degrading bacteria is a suitable option for remediation of diesel-contaminated water in floating wetlands. Chemosphere 2020, 240, 124890. [Google Scholar] [CrossRef]
  213. Afzal, M.; Arslan, M.; Müller, J.A.; Shabir, G.; Islam, E.; Tahseen, R.; Anwar-ul-Haq, M.; Hashmat, A.J.; Iqbal, S.; Khan, Q.M. Floating treatment wetlands as a suitable option for large-scale wastewater treatment. Nat. Sustain. 2019, 2, 863–871. [Google Scholar] [CrossRef]
  214. Nanayakkara, C. Floating wetlands for management of algal washout from waste stabilization pond effluent: Case study at hikkaduwa waste stabilization ponds. Engineer 2013, 46, 63–74. [Google Scholar]
  215. Weragoda, S.; Jinadasa, K.; Zhang, D.Q.; Gersberg, R.M.; Tan, S.K.; Tanaka, N.; Jern, N.W. Tropical application of floating treatment wetlands. Wetlands 2012, 32, 955–961. [Google Scholar] [CrossRef]
  216. Lopardo, C.R.; Zhang, L.; Mitsch, W.J.; Urakawa, H. Comparison of nutrient retention efficiency between vertical-flow and floating treatment wetland mesocosms with and without biodegradable plastic. Ecol. Eng. 2019, 131, 120–130. [Google Scholar] [CrossRef]
  217. Wang, C.-Y.; Sample, D.J. Assessment of the nutrient removal effectiveness of floating treatment wetlands applied to urban retention ponds. J. Environ. Manag. 2014, 137, 23–35. [Google Scholar] [CrossRef] [PubMed]
  218. Abhilash, P.; Jamil, S.; Singh, N. Transgenic plants for enhanced biodegradation and phytoremediation of organic xenobiotics. Biotechnol. Adv. 2009, 27, 474–488. [Google Scholar] [CrossRef]
  219. Xie, W.-Y.; Huang, Q.; Li, G.; Rensing, C.; Zhu, Y.-G. Cadmium accumulation in the rootless macrophyte Wolffia globosa and its potential for phytoremediation. Int. J. Phytorem. 2013, 15, 385–397. [Google Scholar] [CrossRef] [PubMed]
  220. Rezania, S.; Din, M.F.M.; Taib, S.M.; Dahalan, F.A.; Songip, A.R.; Singh, L.; Kamyab, H. The efficient role of aquatic plant (water hyacinth) in treating domestic wastewater in continuous system. Int. J. Phytorem. 2016, 18, 679–685. [Google Scholar] [CrossRef] [Green Version]
  221. Colares, G.S.; Dell’Osbel, N.; Wiesel, P.G.; Oliveira, G.A.; Lemos, P.H.Z.; da Silva, F.P.; Lutterbeck, C.A.; Kist, L.T.; Machado, Ê.L. Floating treatment wetlands: A review and bibliometric analysis. Sci. Total Environ. 2020, 714, 136776. [Google Scholar] [CrossRef]
  222. Ibekwe, A.M.; Lyon, S.; Leddy, M.; Jacobson-Meyers, M. Impact of plant density and microbial composition on water quality from a free water surface constructed wetland. J. Appl. Microbiol. 2007, 102, 921–936. [Google Scholar] [CrossRef]
  223. Chance, L.M.G.; White, S.A. Aeration and plant coverage influence floating treatment wetland remediation efficacy. Ecol. Eng. 2018, 122, 62–68. [Google Scholar] [CrossRef]
  224. Wu, H.; Zhang, J.; Ngo, H.H.; Guo, W.; Hu, Z.; Liang, S.; Fan, J.; Liu, H. A review on the sustainability of constructed wetlands for wastewater treatment: Design and operation. Bioresour. Technol. 2015, 175, 594–601. [Google Scholar] [CrossRef] [PubMed]
  225. Liu, H.; Hu, Z.; Zhang, J.; Ngo, H.H.; Guo, W.; Liang, S.; Fan, J.; Lu, S.; Wu, H. Optimizations on supply and distribution of dissolved oxygen in constructed wetlands: A review. Bioresour. Technol. 2016, 214, 797–805. [Google Scholar] [CrossRef] [PubMed]
  226. Austin, D.; Nivala, J. Energy requirements for nitrification and biological nitrogen removal in engineered wetlands. Ecol. Eng. 2009, 35, 184–192. [Google Scholar] [CrossRef]
  227. Chen, M.; Wu, X.; Chen, Y.; Dong, M. Mechanism of nitrogen removal by adsorption and bio-transformation in constructed wetland systems. Chin. J. Environ. Eng. 2009, 3, 223–228. [Google Scholar]
  228. Pan, J.; Fei, H.; Song, S.; Yuan, F.; Yu, L. Effects of intermittent aeration on pollutants removal in subsurface wastewater infiltration system. Bioresour. Technol. 2015, 191, 327–331. [Google Scholar] [CrossRef]
  229. Hu, Y.; Zhao, Y.; Zhao, X.; Kumar, J.L. High rate nitrogen removal in an alum sludge-based intermittent aeration constructed wetland. Environ. Sci. Technol. 2012, 46, 4583–4590. [Google Scholar] [CrossRef] [Green Version]
  230. Ahn, K.-H.; Song, K.-G.; Choa, E.; Cho, J.; Yun, H.; Lee, S.; Me, J. Enhanced biological phosphorus and nitrogen removal using a sequencing anoxic/anaerobic membrane bioreactor (SAM) process. Desalination 2003, 157, 345–352. [Google Scholar] [CrossRef]
  231. Wang, C.-Y.; Sample, D.J.; Day, S.D.; Grizzard, T.J. Floating treatment wetland nutrient removal through vegetation harvest and observations from a field study. Ecol. Eng. 2015, 78, 15–26. [Google Scholar] [CrossRef]
  232. Ong, S.-A.; Uchiyama, K.; Inadama, D.; Ishida, Y.; Yamagiwa, K. Performance evaluation of laboratory scale up-flow constructed wetlands with different designs and emergent plants. Bioresour. Technol. 2010, 101, 7239–7244. [Google Scholar] [CrossRef]
  233. Dunqiu, W.; Shaoyuan, B.; Mingyu, W.; Qinglin, X.; Yinian, Z.; Hua, Z. Effect of artificial aeration, temperature, and structure on nutrient removal in constructed floating islands. Water Environ. Res. 2012, 84, 405–410. [Google Scholar] [CrossRef]
  234. Fahid, M.; Ali, S.; Shabir, G.; Rashid Ahmad, S.; Yasmeen, T.; Afzal, M.; Arslan, M.; Hussain, A.; Hashem, A.; Abd Allah, E.F. Cyperus laevigatus L. Enhances Diesel Oil Remediation in Synergism with Bacterial Inoculation in Floating Treatment Wetlands. Sustainability 2020, 12, 2353. [Google Scholar] [CrossRef] [Green Version]
  235. Saleem, H.; Rehman, K.; Arslan, M.; Afzal, M. Enhanced degradation of phenol in floating treatment wetlands by plant-bacterial synergism. Int. J. Phytorem. 2018, 20, 692–698. [Google Scholar] [CrossRef] [PubMed]
  236. El-Esawi, M.A.; Alaraidh, I.A.; Alsahli, A.A.; Ali, H.M.; Alayafi, A.A.; Witczak, J.; Ahmad, M. Genetic variation and alleviation of salinity stress in barley. Molecules 2018, 23, 2488. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  237. Vwioko, E.; Adinkwu, O.; El-Esawi, M.A. Comparative Physiological, Biochemical and Genetic Responses to Prolonged Waterlogging Stress in Okra and Maize Given Exogenous Ethylene Priming. Front. Physiol. 2017, 8, 632. [Google Scholar] [CrossRef]
  238. El-Esawi, M.A.; Al-Ghamdi, A.A.; Ali, H.M.; Alayafi, A.A.; Witczak, J.; Ahmad, M. Analysis of Genetic Variation and Enhancement of Salt Tolerance in French Pea (Pisum Sativum L.). Int. J. Mol. Sci. 2018, 19, 2433. [Google Scholar] [CrossRef] [Green Version]
  239. Hossen, M.Z.; Hussain, M.E.; Hakim, A.; Islam, K.; Uddin, M.N.; Azad, A.K. Biodegradation of reactive textile dye Novacron Super Black G by free cells of newly isolated Alcaligenes faecalis AZ26 and Bacillus spp obtained from textile effluents. Heliyon 2019, 5, e02068. [Google Scholar] [CrossRef] [Green Version]
  240. Pavlineri, N.; Skoulikidis, N.T.; Tsihrintzis, V.A. Constructed floating wetlands: A review of research, design, operation and management aspects, and data meta-analysis. Chem. Eng. J. 2017, 308, 1120–1132. [Google Scholar] [CrossRef]
  241. Thullen, J.S.; Sartoris, J.J.; Walton, W.E. Effects of vegetation management in constructed wetland treatment cells on water quality and mosquito production. Ecol. Eng. 2002, 18, 441–457. [Google Scholar] [CrossRef]
  242. Walton, W.E.; Jiannino, J.A. Vegetation management to stimulate denitrification increases mosquito abundance in multipurpose constructed treatment wetlands. J. Am. Mosq. Control Assoc. 2005, 21, 22–27. [Google Scholar] [CrossRef]
  243. Francesco, D. Biomass recovery from invasive species management in wetlands. Biomass Bioenergy 2017, 105, 259–265. [Google Scholar]
  244. Lishawa, S.C.; Lawrence, B.A.; Albert, D.A.; Larkin, D.J.; Tuchman, N.C. Invasive species removal increases species and phylogenetic diversity of wetland plant communities. Ecol. Evol. 2019, 9, 6231–6244. [Google Scholar] [CrossRef] [PubMed] [Green Version]
Figure 1. Schematic representation of floating treatment wetlands (FTWs) and pollutants removal process.
Figure 1. Schematic representation of floating treatment wetlands (FTWs) and pollutants removal process.
Sustainability 12 05801 g001
Table 1. Characteristics of textile wastewater.
Table 1. Characteristics of textile wastewater.
Temp (°C)35–45 33–4535–4525.442 38 38
pH6.0–10.09.2–115.5–10.56–108.512.93 7.8 10.78.8
EC (μS/cm) 8.07 7.18.4 8.2
DO (mg/L) 0.84
Color (Pt–Co)50–2500 50–250045653 (m−1) 35.5 (m−1)68 (m−1) 66 (m−1)
COD (mg/L)150–10,000465–1400150–10,000150–12,000433.781310904714931734 513
BOD (mg/L)100–4000130–820100–400080–6000224.64221412491901478201
Total solids (mg/L) 3600–6540 5125 49615420 5420
TSS (mg/L)100–5000360–370100–500015–800024439110043913246438324
TDS (mg/L)1800–60003230–6180 1500–60002900–310025704834 4569516490605251
Total Alkalinity (mg/L)500–8001250–3160
Hardness (mg/L) 410 380
Total settleable solids (mg/L) 24 38
Total Organic Carbon (mg/L) 301 166230 201
TN (mg/L) 55.8
TP (mg/L) 13
Phenol (mg/L) 0.86 0.85
Chlorine (mg/L) 1000–6000 600
Chlorides (mg/L)1000–6000 200–6000 846 1382 1383
Free chlorine (mg/L) <10
TA (mg/L) as CaCo3 500–800
TH (mg/L) as CaCo3
TKN (mg/L) 70–8070–80
Phosphate (mg/L) <10 16.4
Sulphates (mg/L) 500–700600–1000412 310 311
Sulphides (mg/L) 5–20
Oil and grease (mg/L) 10–5010–3028
Nitrogen (mg/L) 28.6 28.7
Zink (mg/L) 3–6<10
Nickel (mg/L) <10 2.0 0.1257.6 7.57
Manganese (mg/L) <10
Iron (mg/L) <10 3.3 1.17114.3 14.4
Copper (mg/L) 2–6<10 0.503
Boron (mg/L) <10
Arsenic (mg/L) <10 0.0250.90
Silica (mg/L) <15
Mercury (mg/L) <10
Fluorine (mg/L) <10
Chromium (mg/L) 2–5 0.21 0.8129.73.79.67
Potassium (mg/L) 30–50 858 242
Sodium (mg/L)610–2175 400–21757000 1656 1560
Cadmium (mg/L) 0.27 0.880.800.88
Calcium (mg/L) 80.16 110
Magnesium (mg/L) 48.6 65
Sulfate (mg/L) 412.54
Phosphate (mg/L) 10.08
Nitrate (mg/L) 24
Lead (mg/L) 0.880 0.40
Phosphorous (mg/L) 16.4
Aluminum (mg/L) 2.5
EC: Electrical Conductivity; DO: Dissolved Oxygen; COD: Chemical Oxygen Demand; BOD: Biological Oxygen Demand; TSS: Total Suspended Solids; TDS: Total Dissolved Solids; TN: Total Nitrogen; TP: Total Phosphorus; TA: Total Alkalinity; TH: Total Hardness; TKN: Total Kjeldahl Nitrogen.
Table 2. Various techniques for the treatment of textile wastewater and their drawbacks.
Table 2. Various techniques for the treatment of textile wastewater and their drawbacks.
ChemicalCombined ElectrocoagulationThe pH should be maintained below 6 during the process[79,80]
Coagulation and Adsorption by AlumIncrease the concentration of sulfate and sulfide[81]
OzonationIt has low COD reduction capacity[82]
Chemical coagulationIt is a slow technique and large amount of sludge is produced[83,84]
Electrochemical oxidationSecondary salt contamination[66]
CoagulationCoagulants can be associated with diseases like cancer or Alzheimer’s[85,86]
Electrochemical technologyProduce undesirable by-products that can be harmful for environment[87,88]
Ion exchange methodNot effective for all dyes[89]
Photochemical SonolysisRequires a lot of dissolved oxygen, high cost, and produces undesirable by-products[90]
Coagulation-photocatalytic treatment by nanoparticlesSludge production, difficulty of light penetration in dark and colored wastewaters, high costs of nanoparticles preparation, and limited cycles of nanoparticles usage[91]
Fenton and Photo-Fenton processSludge production, accumulation of unused ferrous ions, and difficult maintenance of pH[92]
PhysicalAdsorption/filtration (commercially activated carbon)High cost of materials, costly operation, may not work with certain dyes and metals, performance depends upon the material types[11]
AdsorptionIt is a costly process[93]
Membrane based treatmentMembrane failing may happen, and costly method[67,94]
Pilot-scale bio-filterBio-filter has low efficiency to metabolize hydrophobic volatile organic compounds because of the massive transfer limitations[95]
Pressure-driven membranesSensitivity to fouling and scaling[96,97]
BiologicalConstructed wetlandsHigh retention time and large area required for establishment[66,98]
Use of White-rot fungi along with bioreactorIt has long hydraulic retention time and requires large reactors[99,100]
MicroalgaeConditions hard to maintain, selection of suitable algae is critical[101]
Duckweed and algae pondsInefficient removal of heavy metals[102,103]
Table 3. Application of bacteria for dye removal from textile wastewater.
Table 3. Application of bacteria for dye removal from textile wastewater.
Bacillus firmusReactive Blue 160[149]
Oerskovia paurometabolaAcid Red 14[150]
Pseudomonas aeruginosa and Thiosphaera pantotrophaReactive Yellow 14[151]
Enterobacter sp. CV–S1Crystal Violet[152]
Serratia sp. RN34Reactive Yellow 2[153]
Paracoccus sp. GSM2Reactive Violet 5[154]
Staphylococcus hominis RMLRT03Acid Orange[155]
Bacillus cereus RMLAU1Orange II (Acid Orange 7)[156]
Enterococcus faecalis strain ZLAcid Orange 7[157]
Pseudomonas aeruginosa strain BCHOrange 3R (RO3R)[158]
Anoxybacillus pushchinoensis, Anoxybacillus kamchatkensis and Anoxybacillus flavithermusReactive Black 5[159]
Citrobacter sp. CK3Reactive Red 180[160]
Bacillus Fusiformis kmk 5Disperse Blue 79 (DB79) and Acid Orange 10 (AO10)[161]
Pseudomonas sp. SUK1Red BLI[162]
Brevibacillus sp.Toluidine Blue dye (TB)[163]
Bacterial strains 1CX and SAD4iAcid Orange 7[164]
Pseudomonas luteolaAzo Dye RP2B[165]
Table 4. Use of various species of macrophytes in floating treatment wetlands.
Table 4. Use of various species of macrophytes in floating treatment wetlands.
CountryPlant NameWastewaterRemoval EfficiencyReference
ArgentinaTypha domingensisSynthetic runoff effluentAchieved 95% removal of total phosphorus, soluble reactive phosphorus, NH4+ and NO3[205]
AustraliaCarex appressaRunoff from low density residential areaThe pollutants removal performance was 80% for TSS, 53% for total phosphorus, 17% for total nitrogen [206]
ChinaIris pseudacorusSynthetic secondary effluentAchieved 89.4% removal of TN in one day retention time[207]
ChinaCyperus ustulatusDomestic wastewaterThe average removal efficiency for total microcystin-RR and microcystin-LR were 63.0% and 66.7%, respectively[208]
IndonesiaChrysopogon zizanioidesTextile wastewaterThe average removal rate for chromium was 40%, BOD was 98.47%, and COD was 89.05%[209]
ItalyPhragmites australis, Carex elata, Juncus effusus, Typha latifolia, Chrysopogon zizanioides, Sparganium erectum, and Dactylis glomerataResurgent waterThe COD, BOD, and TP were reduced by 66%, 52%, and 65%, respectively [210]
New ZealandCarex virgateStorm waterThe pond with FTWs achieved 41% TSS, 40% particulate zinc, 39% copper, and 16% dissolved copper removal more than pond without FTWs[111]
New ZealandCarex virgateDomestic wastewaterThe removal rate for both TSS and BOD was more than 93%, TP and dissolve reactive phosphorus removal rate were 44.9% and 29.7%[211]
PakistanPhragmites australisSynthetic diesel oil contaminated waterThe hydrocarbons concentration was reduced to 95.8%, COD to 98.6%, BOD to 97.7%, and phenol to 98.9%[212]
PakistanPhragmites australis, T. domingensis, Leptochloa fusca and Brachia muticaOil contaminated stabilization pitReduced COD 97.4%, BOD 98.9%, TDS 82.4%, hydrocarbons 99.1%, and heavy metals 80%. [108]
PakistanBrachia mutica and Phragmites australisOil field-produced wastewaterThe COD, BOD, and oil contents reduced by 93%, 97%, and 97%, respectively [139]
PakistanPhragmites australis and Typha domingensisTextile wastewaterThe color, COD, and BOD were reduced by 97%, 87%, and 92%, respectively[35]
PakistanBrachiaria muticaSewage effluentThe COD, BOD, and oil contents were approximately reduced by 80%, 95%, and 50%[112]
PakistanTypha domingensis, Pistia stratiotes and Eichhornia crassipesTextile effluentThe average reduction rate for color, COD, and BOD was 57%, 72%, and 78%, respectively[138]
PakistanPhragmites australis, T. domingensis, Leptochloa fusca and Brachia muticaOil contaminated stabilization pitThe COD, BOD, and TDS contents were reduced by 79%, 88%, and 65% [213]
Sri LankaEichhornia crassipesSewage waterThe removal rate was 74.8% for TP and 55.8% for TN[214]
Sri LankaTypha angustifolia and Canna iridifloraSewage wastewaterAchieved 80% reduction in BOD and NH4+-N, and 40% reduction in NO3-N[215]
USASpartina patensSynthetic marine aquaculture effluentThe TP concentration was dropped to ranging from 17–40%[216]
USAPontederia cordata and Schoenoplectus tabernaemontaniUrban runoffThe TP and TN concentration were dropped to 60% and 40% in treated wastewater [217]
Table 5. Inoculation of bacteria in floating treatment wetlands to enhance remediation potential.
Table 5. Inoculation of bacteria in floating treatment wetlands to enhance remediation potential.
WastewaterPlant SpecieInoculated BacteriaPollutant RemovalRetention PeriodReference
River waterPhragmites australis, Typha domingensis, Brachia mutica, Leptochloa fuscaAeromonas salmonicida, Pseudomonas indoloxydans, Bacillus cerus, Pseudomonas gessardii, and Rhodococcus sp.Significant reduction in trace metals contents (Fe, Mn, Ni, Pb, and Cr) 5 weeks[123]
Diesel contaminated water
(1%, w/v)
Phragmites australisAcinetobacter sp. BRRH61, Bacillus megaterium RGR14
and Acinetobacter iwoffii AKR1
95.8% hydrocarbon, 98.6% chemical oxygen demand (COD), 97.7% biological oxygen demand (BOD), 95.2%, total organic carbon (TOC), 98.9% Phenol removal 3 months[212]
Textile effluentPhragmites australisAcinetobacter junii, Pseudomonas indoloxydans, and Rhodococcus sp.97% color, 87% COD, and 92% BOD removal8 days[38]
Oil contaminated waterPhragmites australis
T. domingensis
Leptochloa fusca
Brachiaria mutica
inoculated with bacteria
Ochrobactrum intermedium R2, Microbacterium oryzae R4, Pseudomonas aeruginosa R25, P. aeruginosa R21, Acinetobacter sp. LCRH81, Klebsiella sp. LCRI-87, Acinetobacter sp. BRSI56, P. aeruginosa BRRI54,
Bacillus subtilus LORI66, and
Acinetobacter junii TYRH47.
97.43% COD, 98.83% BOD, 82.4% TDS, 99.1% hydrocarbon content, and 80% heavy metal removal18 months [108]
Phenol contaminated waterTypha domingensisAcinetobacter lwofii ACRH76, Bacillus cereus LORH97, and Pseudomonas sp. LCRH90COD was reduced from 1057 to 97 mg/L; BOD5 from 423 to 64 mg/L, and TOC from 359 to 37 mg/L
Phenol removal of 0.166 g/m2/day
15 days[235]
River waterPhragmites australis, Brachia muticaAeromonas
Salmonicida, Bacillus cerus
Pseudomonas indoloxydans,
Pseudomonas gessardii, and
Rhodococcus sp.
85.9% COD, 83.3% BOD, and 86.6% TOC reduction, respectively96 h[146]
Oil field wastewaterBrachiara mutica and Phragmites australisBacillus subtilis LORI66, Klebsiella sp. LCRI87, Acinetobacter Junii TYRH47, Acinetobacter sp. LCRH8197% COD 93%, and 97% BOD reduction, respectively42 days[139]
Oil field produced wastewaterTypha domingensisBacillus subtilis LORI66, Klebsiella sp. LCRI87, Acinetobacter Junii TYRH47, and Acinetobacter sp. BRSI56 95% Hydrocarbon, 90% COD, and 93% BOD content removal42 days[175]
Sewage effluentBrachiaria muticaAcinetobacter sp. strain BRSI56, Bacillus cereus strain BRSI57, and Bacillus licheniformis strain BRSI58Reduction in COD, BOD, Total nitrogen (TN), and phosphate (PO4)8 days[112]

Share and Cite

MDPI and ACS Style

Wei, F.; Shahid, M.J.; Alnusairi, G.S.H.; Afzal, M.; Khan, A.; El-Esawi, M.A.; Abbas, Z.; Wei, K.; Zaheer, I.E.; Rizwan, M.; et al. Implementation of Floating Treatment Wetlands for Textile Wastewater Management: A Review. Sustainability 2020, 12, 5801.

AMA Style

Wei F, Shahid MJ, Alnusairi GSH, Afzal M, Khan A, El-Esawi MA, Abbas Z, Wei K, Zaheer IE, Rizwan M, et al. Implementation of Floating Treatment Wetlands for Textile Wastewater Management: A Review. Sustainability. 2020; 12(14):5801.

Chicago/Turabian Style

Wei, Fan, Munazzam Jawad Shahid, Ghalia S. H. Alnusairi, Muhammad Afzal, Aziz Khan, Mohamed A. El-Esawi, Zohaib Abbas, Kunhua Wei, Ihsan Elahi Zaheer, Muhammad Rizwan, and et al. 2020. "Implementation of Floating Treatment Wetlands for Textile Wastewater Management: A Review" Sustainability 12, no. 14: 5801.

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop