Special Issue "Microbiological Wastewater Treatment"

A special issue of Microorganisms (ISSN 2076-2607). This special issue belongs to the section "Environmental Microbiology".

Deadline for manuscript submissions: closed (30 September 2019).

Special Issue Editor

Prof. Stephen R. Smith
E-Mail Website
Guest Editor
Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
Interests: agricultural utilisation; biosolids; biowaste; fertiliser value; environmental impact; human health
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Special Issue Information

Dear Colleagues,

Wastewater treatment is vital to protect human health and the environment. Biological processes are necessary for the treatment of non-settleable solids and BOD and for nitrification reactions. However, additional demands are increasingly being placed on biological treatment processes to remove nutrients from wastewater and achieve higher environmental standards of treatment. Biological wastewater treatment also produces a residual sludge, which requires treatment and appropriate management. The current biological treatment technologies are based on engineering principles involving suspended or attached growth bioreactors that were developed over 100 years ago. These processes have served society well; however, their microbiology remains relatively poorly understood, and more innovative strategies, technologies, and bioengineering are also required to meet future regulatory policies, service efficiency, value recovery, and consumers’ expectations. For instance, innovation is necessary to design more energy-efficient processes, increase treatment intensification to reduce the footprint of wastewater treatment plants, and utilise wastewater as a resource to produce high-value chemicals and derivatives, reducing costs and waste sludge production and generating revenues. Alternative technologies are also necessary that are appropriate and affordable in a developing country context.

This Special Issue devoted to “Microbiological Wastewater Treatment” aims to present the current state of the art and innovative research that will address these challenges, so that wastewater treatment systems can adapt and be fit for purpose, robust, and resilient for the next 100 years. 

Prof. Stephen R. Smith
Guest Editor

Manuscript Submission Information

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Keywords

  • activated sludge process
  • attached growth
  • bioengineering, biofilm
  • floc
  • nutrient removal
  • resource recovery
  • secondary clarification
  • sludge
  • suspended growth
  • trickling filter
  • wastewater treatment

Published Papers (8 papers)

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Research

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Article
Energy-Efficient Single-Stage Nitrite Shunt Denitrification with Saline Sewage through Concise Dissolved Oxygen (DO) Supply: Process Performance and Microbial Communities
Microorganisms 2020, 8(6), 919; https://doi.org/10.3390/microorganisms8060919 - 18 Jun 2020
Cited by 1 | Viewed by 911
Abstract
Single-stage nitrite shunt denitrification (through nitrite rather than nitrate) with low dissolved oxygen (DO) supply is a better alternative in terms of energy-efficiency, short-footprint, and low C/N-ratio requirement. This study investigates the optimal DO level with temperature effect, with saline sewage at the [...] Read more.
Single-stage nitrite shunt denitrification (through nitrite rather than nitrate) with low dissolved oxygen (DO) supply is a better alternative in terms of energy-efficiency, short-footprint, and low C/N-ratio requirement. This study investigates the optimal DO level with temperature effect, with saline sewage at the fixed hydraulic and solids retention times of 8 h and 8 d, respectively. Moreover, 16S rRNA gene sequencing analysis corresponding with total nitrogen (TN) and chemical oxygen demand (COD) removals in each operating condition were performed. Results showed that DO of 0.3 mg/L at 20 °C achieved over 60.7% and over 97.9% of TN and COD removal, respectively, suggesting that such condition achieved effective nitrite-oxidizing bacteria inhibition and efficient denitrification. An unexpected finding was that sulfur-reducing Haematobacter and nitrogen-fixing Geofilum and Shinella were highly abundant with the copredominance of ammonia-oxidizing Comamonas and Nitrosomonas, nitrite-oxidizing Limnohabitans, and denitrifying Simplicispira, Castellaniella, and Nitratireductor. Further, canonical correspondence analysis (CCA) with respect to the operating conditions associated with phenotype prediction via R-based tool Tax4Fun was performed for a preliminary diagnosis of microbial functionality. The effects of DO, temperature, nitrite, and nitrate in various extents toward each predominant microbe were discussed. Collectively, DO is likely pivotal in single-stage nitrite shunt denitrification, as well as microbial communities, for energy-efficient saline sewage treatment. Full article
(This article belongs to the Special Issue Microbiological Wastewater Treatment)
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Article
Organic Contaminant Biodegradation by Oxidoreductase Enzymes in Wastewater Treatment
Microorganisms 2020, 8(1), 122; https://doi.org/10.3390/microorganisms8010122 - 16 Jan 2020
Cited by 10 | Viewed by 1952
Abstract
Organic contaminants (OCs), such as pharmaceuticals, personal care products, flame retardants, and plasticisers, are societally ubiquitous, environmentally hazardous, and structurally diverse chemical compounds whose recalcitrance to conventional wastewater treatment necessitates the development of more effective remedial alternatives. The engineered application of ligninolytic oxidoreductase [...] Read more.
Organic contaminants (OCs), such as pharmaceuticals, personal care products, flame retardants, and plasticisers, are societally ubiquitous, environmentally hazardous, and structurally diverse chemical compounds whose recalcitrance to conventional wastewater treatment necessitates the development of more effective remedial alternatives. The engineered application of ligninolytic oxidoreductase fungal enzymes, principally white-rot laccase, lignin peroxidase, and manganese peroxidase, has been identified as a particularly promising approach for OC remediation due to their strong oxidative power, broad substrate specificity, low energy consumption, environmental benignity, and cultivability from lignocellulosic waste. By applying an understanding of the mechanisms by which substrate properties influence enzyme activity, a set of semi-quantitative physicochemical criteria (redox potential, hydrophobicity, steric bulk and pKa) was formulated, against which the oxidoreductase degradation susceptibility of twenty-five representative OCs was assessed. Ionisable, compact, and electron donating group (EDG) rich pharmaceuticals and antibiotics were judged the most susceptible, whilst hydrophilic, bulky, and electron withdrawing group (EWG) rich polyhalogenated compounds were judged the least susceptible. OC susceptibility scores were in general agreement with the removal rates reported for experimental oxidoreductase treatments (R2 = 0.60). Based on this fundamental knowledge, and recent developments in enzyme immobilisation techniques, microbiological enzymic treatment strategies are proposed to formulate a new generation of biological wastewater treatment processes for the biodegradation of environmentally challenging OC compounds. Full article
(This article belongs to the Special Issue Microbiological Wastewater Treatment)
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Article
Evaluation and Predictive Modeling of Removal Condition for Bioadsorption of Indigo Blue Dye by Spirulina platensis
Microorganisms 2020, 8(1), 82; https://doi.org/10.3390/microorganisms8010082 - 07 Jan 2020
Cited by 4 | Viewed by 1091
Abstract
Among the different chemical and physical treatments used to remove the color of the textile effluents, bioremediation offers many benefits to the environment. In this study, we determined the potential of Spirulina platensis (S. platensis) for decolorizing indigo blue dye under [...] Read more.
Among the different chemical and physical treatments used to remove the color of the textile effluents, bioremediation offers many benefits to the environment. In this study, we determined the potential of Spirulina platensis (S. platensis) for decolorizing indigo blue dye under different incubation conditions. The microalgae were incubated at different pH (from 4 to 10) to calibrate for the optimal discoloration condition; a pH of 4 was found to be optimal. The biomass concentration in all experiments was 1 g/L, which was able to decolorize the indigo blue dye by day 3. These results showed that S. platensis is capable of removing indigo blue dye at low biomass. However, this was dependent on the treatment conditions, where temperature played the most crucial role. Two theoretical adsorption models, namely (1) a first-order model equation and (2) a second-order rate equation, were compared with observed adsorption vs. time curves for different initial concentrations (from 25 to 100 mg/L). The comparison between models showed similar accuracy and agreement with the experimental values. The observed adsorption isotherms for three temperatures (30, 40, and 50 °C) were plotted, showing fairly linear behavior in the measured range. The adsorption equilibrium isotherms were estimated, providing an initial description of the dye removal capacity of S. platensis. Full article
(This article belongs to the Special Issue Microbiological Wastewater Treatment)
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Article
Profiling Bacterial Diversity and Potential Pathogens in Wastewater Treatment Plants Using High-Throughput Sequencing Analysis
Microorganisms 2019, 7(11), 506; https://doi.org/10.3390/microorganisms7110506 - 29 Oct 2019
Cited by 15 | Viewed by 1666
Abstract
Next-generation sequencing provides new insights into the diversity and structure of bacterial communities, as well as the fate of pathogens in wastewater treatment systems. In this study, the bacterial community structure and the presence of pathogenic bacteria in three wastewater treatment plants across [...] Read more.
Next-generation sequencing provides new insights into the diversity and structure of bacterial communities, as well as the fate of pathogens in wastewater treatment systems. In this study, the bacterial community structure and the presence of pathogenic bacteria in three wastewater treatment plants across Gauteng province in South Africa were studied. The physicochemical results indicated that the quality of wastewater varies considerably from one plant to the others. Proteobacteria, Actinobacteria, Firmicutes, and Chloroflexi were the dominant phyla across the three wastewater treatment plants, while Alphaproteobacteria, Actinobacteria, Bacilli, and Clostridia were the dominant classes. The dominant bacterial functions were highly associated with carbohydrate, energy, and amino acid metabolism. In addition, potential pathogenic bacterial members identified from the influent/effluent samples included Roseomonas, Bacillus, Pseudomonas, Clostridium, Mycobacterium, Methylobacterium, and Aeromonas. The results of linear discriminant analysis (LDA) effect size analysis also confirmed that these bacterial pathogens were significantly abundant in the wastewater treatment systems. Further, the results of this study highlighted that the presence of bacterial pathogens in treated effluent pose a potential contamination risk, transmitted through soil, agriculture, water, or sediments. There is thus a need for continuous monitoring of potential pathogens in wastewater treatment plants (WWTPs) in order to minimize public health risk. Full article
(This article belongs to the Special Issue Microbiological Wastewater Treatment)
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Article
Abundance and Antimicrobial Resistance of Three Bacterial Species along a Complete Wastewater Pathway
Microorganisms 2019, 7(9), 312; https://doi.org/10.3390/microorganisms7090312 - 03 Sep 2019
Cited by 10 | Viewed by 1610
Abstract
After consumption, antibiotic residues and exposed bacteria end up via the feces in wastewater, and therefore wastewater is believed to play an important role in the spread of antimicrobial resistance (AMR). We investigated the abundance and AMR profiles of three different species over [...] Read more.
After consumption, antibiotic residues and exposed bacteria end up via the feces in wastewater, and therefore wastewater is believed to play an important role in the spread of antimicrobial resistance (AMR). We investigated the abundance and AMR profiles of three different species over a complete wastewater pathway during a one-year sampling campaign, as well as including antimicrobial consumption and antimicrobial concentrations analysis. A total of 2886 isolates (997 Escherichia coli, 863 Klebsiella spp., and 1026 Aeromonas spp.) were cultured from the 211 samples collected. The bacterial AMR profiles mirrored the antimicrobial consumption in the respective locations, which were highest in the hospital. However, the contribution of hospital wastewater to AMR found in the wastewater treatment plant (WWTP) was below 10% for all antimicrobials tested. We found high concentrations (7–8 logs CFU/L) of the three bacterial species in all wastewaters, and they survived the wastewater treatment (effluent concentrations were around 5 log CFU/L), showing an increase of E. coli in the receiving river after the WWTP discharge. Although the WWTP had no effect on the proportion of AMR, bacterial species and antimicrobial residues were still measured in the effluent, showing the role of wastewater contamination in the environmental surface water. Full article
(This article belongs to the Special Issue Microbiological Wastewater Treatment)
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Article
Wastewater Biofilm Photosynthesis in Photobioreactors
Microorganisms 2019, 7(8), 252; https://doi.org/10.3390/microorganisms7080252 - 10 Aug 2019
Cited by 11 | Viewed by 1473
Abstract
Photosynthetic performance of algal-bacterial biofilms from an Italian wastewater treatment plant was studied in a flow-lane photobioreactor at different irradiances, temperatures, and flow regime to evaluate the effects of these environmental parameters on biofilms’ functioning, in view of application of these communities in [...] Read more.
Photosynthetic performance of algal-bacterial biofilms from an Italian wastewater treatment plant was studied in a flow-lane photobioreactor at different irradiances, temperatures, and flow regime to evaluate the effects of these environmental parameters on biofilms’ functioning, in view of application of these communities in wastewater biological treatment. Pulse amplitude modulated fluorescence was used to estimate the effective quantum yield of PSII (ΔF/Fm’) of the light-acclimated biofilms and to perform rapid light curves (RLCs) for the determination of the photosynthetic parameters (rel.ETRmax, α, Ik). Chl a, ash free dry weight (AFDW), and dry weight (DW) were measured to assess phototrophic and whole biofilm biomass development over time. From the analysis of photosynthetic parameter variation with light intensity, temperature and flow rate, it was possible to identify the set of experimental values favoring biofilm photosynthetic activity. Biomass increased over time, especially at the highest irradiances, where substrata were fastly colonized and mature biofilms developed at all temperatures and flow conditions tested. Full article
(This article belongs to the Special Issue Microbiological Wastewater Treatment)
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Article
The Role of Pseudomonas in Heterotrophic Nitrification: A Case Study on Shrimp Ponds (Litopenaeus vannamei) in Soc Trang Province
Microorganisms 2019, 7(6), 155; https://doi.org/10.3390/microorganisms7060155 - 29 May 2019
Cited by 5 | Viewed by 1401
Abstract
Based on a total of 6,295,650 sequences from the V3 and V4 regions (16S ribosomal RNA), the composition of the microorganism communities in the water of three Litopenaeus vannamei (Decapoda, Whiteleg shrimp; Soc Trang, Vietnam) ponds were identified. Pseudomonas (10–20.29%), Methylophilus (13.26–24.28%), and [...] Read more.
Based on a total of 6,295,650 sequences from the V3 and V4 regions (16S ribosomal RNA), the composition of the microorganism communities in the water of three Litopenaeus vannamei (Decapoda, Whiteleg shrimp; Soc Trang, Vietnam) ponds were identified. Pseudomonas (10–20.29%), Methylophilus (13.26–24.28%), and Flavobacterium (2.6–19.29%) were the most abundant genera. The total ammonia (TAN) concentration (p = 0.025) and temperature (p = 0.015) were significantly correlated with the relative abundance of Pseudomonas in two bacterial communities (ST1, ST4), whereas the predictive functions of microorganism communities based on 16S rRNA gene data was estimated using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUST), which showed that nitrogen metabolism was significantly negatively correlated (p = 0.049) with TAN concentration. The abundance of Pseudomonas and nitrogen metabolism increased with a decrease in TAN concentration. The correlation between TAN concentration and the abundance of Pseudomonas was followed by the isolation, and heterotrophic nitrifying performance analysis was used to confirm our findings. Six Pseudomonas strains capable of heterotrophic nitrification were isolated from the three water samples and showed a complete reduction of 100 mg/L NH4Cl during a 96-h cultivation. These results indicate the potential of applying Pseudomonas in shrimp ponds for water treatment. Full article
(This article belongs to the Special Issue Microbiological Wastewater Treatment)
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Review

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Review
Linking Microbial Community Composition in Treated Wastewater with Water Quality in Distribution Systems and Subsequent Health Effects
Microorganisms 2019, 7(12), 660; https://doi.org/10.3390/microorganisms7120660 - 07 Dec 2019
Cited by 6 | Viewed by 1242
Abstract
The increases in per capita water consumption, coupled in part with global climate change have resulted in increased demands on available freshwater resources. Therefore, the availability of safe, pathogen-free drinking water is vital to public health. This need has resulted in global initiatives [...] Read more.
The increases in per capita water consumption, coupled in part with global climate change have resulted in increased demands on available freshwater resources. Therefore, the availability of safe, pathogen-free drinking water is vital to public health. This need has resulted in global initiatives to develop sustainable urban water infrastructure for the treatment of wastewater for different purposes such as reuse water for irrigation, and advanced waste water purification systems for domestic water supply. In developed countries, most of the water goes through primary, secondary, and tertiary treatments combined with disinfectant, microfiltration (MF), reverse osmosis (RO), etc. to produce potable water. During this process the total bacterial load of the water at different stages of the treatment will decrease significantly from the source water. Microbial diversity and load may decrease by several orders of magnitude after microfiltration and reverse osmosis treatment and falling to almost non-detectable levels in some of the most managed wastewater treatment facilities. However, one thing in common with the different end users is that the water goes through massive distribution systems, and the pipes in the distribution lines may be contaminated with diverse microbes that inhabit these systems. In the main distribution lines, microbes survive within biofilms which may contain opportunistic pathogens. This review highlights the role of microbial community composition in the final effluent treated wastewater, biofilms formation in the distribution systems as the treated water goes through, and the subsequent health effects from potential pathogens associated with poorly treated water. We conclude by pointing out some basic steps that may be taken to reduce the accumulation of biofilms in the water distribution systems. Full article
(This article belongs to the Special Issue Microbiological Wastewater Treatment)
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