Search Results (29)

This study compared the effectiveness of the Sequencing Batch Biofilter Granular Reactor (SBBGR) plant with and without the integration of ozone (BIO-CHEM process) in the remediation of medium-aged landfill leachate. Special attention is given to the removal of per- and polyfluoroalkyl substances (PFAS) as a group of bioaccumulative and persistent pollutants. The findings highlight the high SBBGR performance under biological process only for key wastewater contaminants, with 82% for chemical oxygen demand (COD), 86% for total nitrogen, and 98% for ammonia. Moderate removal was observed for total (TSS) and volatile (VSS) suspended solids (41% and 44%, respectively), while phosphorus and colour removal remained limited. Remarkably, the SBBGR process achieved complete removal of long-chain PFAS, while its performance declined for shorter-chain PFAS. BIO-CHEM process significantly improved COD (87.7%), TSS (84.6%), VSS (86.7%), and colour (92–96%) removal. Conversely, ozonation led to an unexpected increase in the concentrations of several PFAS in the effluent, suggesting ozone-induced desorption from the biomass. SBBGR treatment was characterised by a low specific sludge production (SSP) value, i.e., 5–6 times less than that of conventional biological processes. SSP was further reduced during the application of the BIO-CHEM process. A key finding of this study is a critical challenge for PFAS removal in this combined treatment approach, different from other ozone-based methods. Full article

Objectives: This study evaluates the efficacy of existing and new aerosol mitigation methods during nebulization (Neb) in combination with high-flow nasal cannula (HFNC) oxygen supplementation and non-invasive ventilation (NIV). Methods: We recorded fugitive aerosol particle concentrations over time and assessed the peak (P) and area (A) efficacy of active and passive mitigation methods, comparing them to a no-mitigation condition. Peak efficacy was measured by the reduction in maximum aerosol concentration, while area efficacy was quantified by the reduction of the area under the aerosol concentration–time curve. Results: For HFNC with Neb, we found that active mitigation using a mask with a biofilter and a fan (referred to as the aerosol barrier mask) significantly outperformed passive mitigation with a face mask. The peak and area efficacy for aerosol reduction were 99.0% and 96.4% for active mitigation and 35.9% and 7.6% for passive mitigation, respectively. For NIV with Neb, the active mitigation method, using a box with a biofilter and fan, also outperformed passive mitigation using only the box. The peak and area efficacy for aerosol reduction were 92.1% and 85.5% for active mitigation and 53.7.0% and 25.4% for passive mitigation, respectively. Conclusion: We concluded that active mitigation set up systems advantageous for effective reduction of airborne aerosols during aerosol generated procedures. Full article

Volatile organic compounds (VOC) are major contributors to the burgeoning air pollution issue, predominantly from industrial areas, with well-documented environmental and health risks, which demand efficient and sustainable control policies. This review analyzes the current technological challenges and investigates recent developments in biological treatment technologies for VOC-contaminated off-gases, including biofilters, biotrickling filters, and bioscrubber, as well as emerging technologies, such as bioaugmentation and microbial fuel cells (MFCs). Operational performance, economic feasibility, and adaptability to various industrial applications are assessed, alongside opportunities for integration with other technologies, including energy recovery technologies. Biological systems offer considerable advantages regarding cost savings and lower environmental impacts and enhanced operational flexibility, particularly when combined with innovative materials and microbial optimization techniques. Nevertheless, challenges persist, such as choosing the best treatment settings suited to different VOC streams and addressing biofilm control concerns and scalability. Overall, biological VOC treatments are encouraging sustainable solutions, though continued research into reactor design, microbial dynamics, and MFC-based energetic valorization is essential for broader industrial application. These insights cover advancements and highlight the continuous need for innovative prowess to forge sustainable VOC pollution control. Full article

Tire wear particles (TWPs), a form of microplastics (MPs) pollution, are transported into waterbodies through stormwater runoff, leading to environmental pollution and impacts on associated biota. Here, we investigated the effectiveness of stormwater filter socks filled with rice husk biochar or pine tree woodchips in reducing TWP pollution in urban runoff in Oxford, Mississippi. Triplicate runoff samples were collected upstream and downstream of the biofilters at two sites during two storm events at peak flow within minutes of the start of the storm and after 30 min. Samples were analyzed for TWPs using a combination of stereomicroscopy, micro-attenuated total reflectance Fourier transform infrared spectroscopy (µ-ATR-FTIR), and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX). Concentrations (TWPs/L) upstream of the biofilter were variable but highest at the start of the runoff, dropping from an average of 2811 ± 1700 to 476 ± 63 after 30 min at site 1 and from 2702 ± 353 to 2356 ± 884 at site 2. Biochar was more effective than woodchips (p < 0.05) at removing TWPs, reducing concentrations by an average of 97.6% (first use) and 85.3% (second use) compared to 66.2% and 54.2% for woodchips, respectively. Biochar was particularly effective at removing smaller TWPs (<100 µm). Both materials became less effective with use, suggesting fewer available trapping sites and the need for removal and replacement of the material with time. Overall, this study suggests that biochar and woodchips, alone or in combination, deserve further scrutiny as a potential cost-effective and sustainable method to mitigate the transfer of TWPs to aquatic ecosystems and associated biota. Full article

Effective stormwater management is increasingly vital due to climate change impacts, such as intensified rainfall and flooding. Urban expansion, water scarcity, and intensified agriculture demand innovative solutions like Green Stormwater Infrastructure (GSI), including vegetated biofilters, green roofs, wetlands, bioretention systems, and high-rate filtration. These systems, enhanced by natural and engineered filter materials, improve contaminant removal across diverse contexts. Modern practices prioritize retention, infiltration, and groundwater recharge over traditional rapid drainage, reframing stormwater as a resource amid rising extreme weather events. In water-scarce regions, stormwater management offers dual-use potential for drinking and non-drinking applications, addressing freshwater scarcity exacerbated by population growth and climate change. Targeting the “first flush” of pollutants after rainfall allows for more efficient, cost-effective treatment. This paper identifies three key objectives: addressing GSI limitations and exploring new technologies, evaluating treatment train combinations for cost-effective reuse, and advancing urban stormwater treatment research. Various filter media, such as those in green roofs, bioretention systems, and swales, effectively remove pollutants like nutrients, heavy metals, PAHs, and micropollutants. Granular activated carbon (GAC) filters excel at reducing heavy metals and dissolved organic carbon (DOC), with pre-screening via anthracite filters to extend GAC lifespan by trapping sediments and pollutants. Managing emerging contaminants and microplastics remains underexplored and requires further investigation. Full article

Nitrification plays a crucial role in aquatic ecosystems and in the biofilters used in fish farms. Despite their importance, the role of canonical nitrifiers, comammox bacteria, and archaea has not yet been sufficiently investigated. The aim of this study was to characterize the microbiome of the external canister biofilter in a freshwater fish aquarium, with particular focus on the role of comammox Nitrospira and their competition with other nitrifiers. To achieve this, a comprehensive approach combining metagenome sequencing and co-occurrence network analysis was used to study the interactions between microorganisms in portable biofilter. The fish were subjected to a changing feeding regime that affected the ecological relationships and abundance of different microbial taxa. The results showed the presence of two types of nitrifiers in the biofilter: comammox Nitrospira and ammonia-oxidizing archaea (AOA). Five comammox Nitrospira genomes were reconstructed, with comammox clade B being the most abundant with an average abundance of 7.8 ± 0.4%. In addition, two families of archaea were identified: Nitrosopumilaceae and Nitrososphaeraceae, with an average abundance of 4.3 ± 0.4%. Heterotrophs were also abundant in the bacterial community, particularly in the genera Actinomycetota, Planctomycetota, and Pseudomonadota. Network analysis indicated competitive interactions between comammox and heterotrophs, whereas no competition was observed between comammox and AOA. The predominance of comammox Nitrospira, and AOA over canonical nitrifiers emphasizes their better adaptation to oligotrophic environments. This study highlights the importance of competition within the biofilter microbiome and the role of ecological interaction networks, which can contribute to the optimization of water purification systems in RASs. Full article

The management of domestic wastewater in rural areas has always been challenging due to characteristics such as the wide distribution and dispersion of rural households. There are numerous domestic sewage discharge methods used in rural areas, and it is difficult to treat the sewage. To address this problem, decentralized wastewater treatment systems (DWTSs) have been installed around the globe to reuse and recycle wastewater for non-potable uses such as firefighting, toilet flushing, and landscape irrigation. This study compares the currently implemented treatment processes by investigating them from the point of view of their performance and their advantages and disadvantages to provide new ideas for the development of rural wastewater treatment technologies. According to conventional treatment technologies including activated sludge (OD, A/O, A/A/O, SBR), biofilm (biofilter, MBBR, biological contact oxidation, biofluidized bed) and biogas digesters, natural biological treatment technologies including artificial wetlands (surface flow, vertical flow, horizontal submerged flow artificial wetlands), soil percolation systems (slow, fast, subsurface percolation and surface diffusion) and stabilization pond technology and combined treatment technologies are categorized and further described. Full article

De-icing salt used for safe winter driving can have negative impacts on local water quality, vegetation, and soils. This study aimed to evaluate the salt tolerance of reeds (Phragmites australis) against calcium chloride (CaCl₂) and the biofiltration effect of combining it with topsoil biofilters for desalination in roadside ditches. Two experiments were conducted in a controlled environmental greenhouse over a period of 150 days. For the first experiment, the salt tolerance of P. australis was examined after treating reeds with five different concentrations of de-icing salt: 0, 1, 2, 5, and 10 g·L⁻¹. In a second experiment, the effect of combining two topsoil filters (expanded clay and activated carbon), each planted with and without reeds, was investigated under a high CaCl₂ concentration of 10 g·L⁻¹. As the CaCl₂ concentration increased, the electrical conductivity (EC) of soil leachate and the level of salt exchangeable cations (K⁺, Ca²⁺, Na⁺, and Mg²⁺) significantly increased whereas the acidity (pH) significantly decreased (all p ≤ 0.05). No statistical difference was observed in leaf length or width, while plant height, number of leaves, and both fresh and dry weights were significantly increased with increasing CaCl₂ concentrations (p ≤ 0.05). Treatments using topsoil filters, particularly those with activated carbon and reeds, showed the greatest reduction in leachate EC and total exchange cations values. These results suggest that combining P. australis with topsoil filters can assist biofiltration effectively, demonstrating its applicability even in roadside soils subject to extreme levels of de-icing salts. Full article

Genetic epidemiological studies have shown that numerous genetic variants cumulatively increase obesity risk. Although genetically predisposed individuals are more prone to developing obesity, it has been shown that physical activity can modify the genetic predisposition to obesity. Therefore, genetic data obtained from earlier studies, including 30 polymorphisms located in 18 genes, were analyzed using novel methods such as the total genetic score and Biofilter 2.4 software to combine genotypic and phenotypic information for nine obesity-related traits measured before and after the realization of the 12-week training program. The results revealed six genes whose genotypes were most important for post-training changes—LEP, LEPR, ADIPOQ, ADRA2A, ADRB3, and DRD2. Five noteworthy pairwise interactions, LEP × LEPR, ADRB2 × ADRB3, ADRA2A × ADRB3, ADRA2A × ADRB2, ADRA2A × DRD2, and three specific interactions demonstrating significant associations with key parameters crucial for health, total cholesterol (TC), high-density lipoprotein (HDL), and fat-free mass (FFM), were also identified. The molecular basis of training adaptation described in this study would have an enormous impact on the individualization of training programs, which, designed according to a given person’s genetic profile, will be effective and safe intervention strategies for preventing obesity and improving health. Full article

Agro-industrial residue valorization under the umbrella of the circular bioeconomy (CBE) has prompted the search for further forward-thinking alternatives that encourage the mitigation of the industry’s environmental footprint. From this perspective, second-life valorization (viz., thermoplastic composites) has been explored for agro-industrial waste (viz., oil palm empty fruit bunch fibers, OPEFBFs) that has already been used previously in other circular applications (viz., the removal of domestic wastewater contaminants). Particularly, this ongoing study evaluated the performance of raw residues (R-OPEFBFs) within three different size ranges (250–425, 425–600, 600–800 µm) both before and after their utilization in biofiltration processes (as post-adsorbents, P-OPEFBFs) to reinforce a polymer matrix of acrylic resin. The research examined the changes in R-OPEFBF composition and morphology caused by microorganisms in the biofilters and their impact on the mechanical properties of the composites. Smaller R-OPEFBFs (250–425 µm) demonstrated superior mechanical performance. Additionally, the composites with P-OPEFBFs displayed significant enhancements in their mechanical properties (3.9–40.3%) compared to those with R-OPEFBFs. The combination of the three fiber sizes improved the mechanical behavior of the composites, indicating the potential for both R-OPEFBFs and P-OPEFBFs as reinforcement materials in composite applications. Full article

The aim of the research is to assess changes in odour concentration in the ventilated air of a production hall, using different types of biofilter fillings and different types of membranes. Deodorisation was carried out using a mobile combined biofilter at a plant producing lard and liquid oils. Ventilated air from the hall contained organic and inorganic pollutants. Two types of fillings were used for technological tests: stumpwood chips mixed with pine bark and a mix of stumpwood chips with pine bark and green waste compost. Two types of membranes were also used, differing in thickness, permeability, and water resistance. The subjects of the research were the air supplied to the filter, lifted directly from the bed, and the air above the membranes. The deodorisation efficiency—the percentage reduction in the odour concentration value as a result of air flow through the bed and membranes—was calculated. The filtration methods used allowed the selection of the most advantageous technological variant from the point of view of deodorisation effectiveness: a mix of stumpwood chips with pine bark and the Pro Eko Tex UV membrane. It has a total odour reduction efficiency of 99.3–99.9% and has been added to full-scale implementation works. Full article

Brominated disinfection byproducts (DBPs) are a concern to drinking water utilities due to their toxicity and increasing prevalence in water systems. Haloacetic acids (HAAs) are a class of DBPs that are partially regulated by the United States Environmental Protection Agency (USEPA), but regulations are likely to increase as evidenced by the brominated HAAs listed on the USEPA Fourth Unregulated Contaminant Monitoring Rule and Fifth Contaminant Candidate List. Utilities often use a pre-oxidant to assist in their treatment training, but this can lead to increased HAA formation during treatment. In this study, tap water was spiked with bromine (Br₂) at varying concentrations to simulate bromine-to-chlorine ratios found in the natural environment and the DBPs that may be formed from those waters. The water was fed through a bench-scale biological filter (biofilter) with a small layer of fresh granular activated carbon (GAC) media followed by acclimated anthracite media. The HAA species studied were found to be removable by an average of 89.5% through combined GAC filtration and biofiltration. Biodegradation occurred predominantly in the first five minutes for the acclimated anthracite, with minimal additional removal observed at longer empty bed contact times (15 and 30 min EBCT). This study provides recommendations on biofilter parameters for utilities to reduce the formation of both regulated and unregulated HAAs during the drinking water treatment process. Full article

The degradation of water resources is related to anthropic actions such as rapid urbanization and industrial and agricultural activities with inefficient land use and occupation management. Water pollution caused by organic and inorganic contaminants represents a current challenge for researchers and humanity. One of the techniques used to remove pollutants from aquatic environments is bioremediation, through the metabolism of living organisms, and especially phytoremediation, with plants as a decontamination agent. Aiming to demonstrate the current mechanisms, solutions, and perspectives regarding bioremediation, and especially phytoremediation in aquatic environments, a literature review was conducted, highlighting the following subjects: heavy metals as contaminants, phytoremediation, evaluation of resistance mechanisms, removal of heavy metals by microorganisms and biofilters of the artificial floating islands type. From the literature research carried out, it can be concluded that alternatives such as macrophyte plants have proved to be an effective and efficient alternative with a high potential for removal of contaminants in aquatic environments, including concomitantly with microorganisms. There was no mechanism well-defined for specific absorption of heavy metals by plants; however, some results can indicate that if there was sporadic contamination with some contaminants, the plants can be indicators with some adsorption and absorption, even with low concentration in the watercourse by the moment of the evaluation. It is necessary to study bioremediation methods, resistance mechanisms, tolerance, and removal efficiencies for each biological agent chosen. Within the bioremediation processes of aquatic environments, the use of macrophyte plants with a high capacity for phytoremediation of metals, used combined with bioremediating microorganisms, such as biofilters, is an interesting perspective to remove contaminants. Full article

Spatial separation into acidogenic and methanogenic stages is considered a viable option to ensure process stability, energy efficiency and the better control of key anaerobic digestion (AD) parameters. The elucidation of the optimal modes of two-stage AD for the maximization of the recovery of biofuels (H₂ and CH₄) is still an urgent task, the main optimization criteria being the highest energy yield (EY) and energy production rate (EPR). In this work, a response surface methodology was used for an optimization of energy production from the two-stage mesophilic–thermophilic AD of cheese whey (CW). Three dilution rates of CW, providing values of 10.9, 14.53 and 21.8 g for the chemical oxygen demand (COD)/L in the influent and three hydraulic retention times (HRTs) (1, 2 and 3 days) in methanogenic biofilters at a constant HRT in an acidogenic biofilter of 0.42 days, were tested to optimize the EY and EPR. The desirability approach produced combined optimum conditions as follows: the dilution rate of the CW provided 17.58 g COD/L (corresponding to OLR of 6.5 g COD/(L·day)) in the influent and a HRT in the methanogenic biofilter of 2.28 days, both of which provided a maximum EPR of 80.263 kJ/(L·day) and EY of 9.56 kJ/g COD, with an overall desirability value of 0.883. Full article

People spend most of their time indoors, and prolonged exposure to pollution can harm their health. The degradation of indoor air quality (IAQ) has raised serious issues. Botanical biofilters are an exciting solution for lowering indoor air pollution. However, plants cultivated inside under low light intensity (10–50 μmole PAR m⁻² s⁻¹) generate CO₂ in the indoor atmosphere. Combining C3 (Calvin Cycle) and Crassulacean Acid metabolism (CAM) plants may be able to address this problem by lowering CO₂ emission levels and enhancing the efficiency of pollution removal by removing the primary indoor air pollutants from actual interior settings, including carbon dioxide (CO₂), formaldehyde (HCHO), particulate matter (PM_2.5 and PM₁₀), and total volatile organic compounds (TVOCs). As a result, a successful botanical biofilter made of several plants was researched. Indoor plants can phytoremediate a variety of indoor contaminants. However, just a few studies have demonstrated its efficacy in practical contexts. Due to the harsh winter, apartments in South Korea are frequently closed, necessitating the measurement of interior air pollution concentration in real-time. Four apartments (APT I through APT IV) with various ventilation and indoor plant setups were selected for this investigation. Various combinations of indoor environments (ventilation, low light) and a combination of C3 and CAM indoor plants as a botanical biofilter were used to study the sites over two months. Current research indicates that combining a botanical biofilter with ventilation can reduce levels of CO₂, TVOCs, HCHO, PM_2.5, and PM₁₀ by 76%, 87%, 75%, 52%, and 51%, respectively. The current study concluded that different indoor potted plants provide an effective, affordable, self-regulating, sustainable option for enhancing indoor air quality and, consequently, human well-being and productivity in small, cramped places. Full article