Water Environment Research最新文献

Anaerobic digestion (AD) of condensate or aqueous pyrolysis liquid (APL) derived from municipal wastewater solids was successfully achieved both as a sole substrate and as a co-digestate with synthetic sludge, overcoming toxicity challenges previously associated with APL degradation. Key strategies that enhanced APL conversion to methane included optimizing the solids retention time (SRT) and organic loading rate (OLR) to mitigate APL toxicity, using an acclimated inoculum, and employing APL ozonation prior to digestion. Gas chromatography-mass spectrometry analysis confirmed APL constituents were removed in the process. Inoculum biomass from an industrial waste digester (IB) exhibited better performance in APL degradation compared to inoculum from a municipal digester (MB). APL ozonation enhanced methane production in IB-inoculated co-digesters, achieving 98% of the maximum stoichiometric methane. Microbial community analysis showed that hydrogenotrophic methanogens predominated in syntrophy with acetate oxidizing bacteria in IB-inoculated reactors, whereas both acetoclastic and hydrogenotrophic methanogens were present in MB-inoculated co-digesters. This study demonstrates that APL can be digested alone or as a co-substrate, emphasizing the importance of appropriate SRT, OLR, and inoculum selection. Co-digestion could be a viable strategy for wastewater resource recovery facilities that operate digesters for sludge treatment and may incorporate wastewater solids pyrolysis in the future.

Biochar possesses abundant pore structures (e.g., micropores, mesopores, and macropores), providing ample attachment sites for microorganisms and facilitating the colonization of methanogenic archaea. Simultaneously, biochar contains rich functional groups (e.g., hydroxyl, carboxyl, and phenolic groups), which can regulate the system pH through mechanisms like ion exchange and adsorption, thus buffering potential acidification issues during anaerobic digestion (AD). Its surface minerals (e.g., K, Ca, and Mg) can also serve as sources of trace elements for microbial metabolism. Biogas slurry is rich in metal ions (e.g., Fe³⁺ and Mg²⁺) and nutrients (e.g., N and P), which can compensate for nutritional deficiencies in waste-activated sludge (WAS), optimizing the nutritional conditions for microbial growth. Both biochar and biochar coupled with biogas slurry can enhance the relative abundance of microorganisms involved in direct interspecies electron transfer (DIET), improving methane production efficiency during AD. However, whether the porosity or the electrical conductivity of biochar predominantly governs its influence on DIET in AD remains unexplored. This study investigated the mechanisms by which biochar coupled with biogas slurry affects the AD of WAS, using two types of bamboo-derived biochar with different specific surface areas (SSAs) and recirculated biogas slurry from a sludge treatment plant. Biogas slurry with a 60% recirculation ratio and biochar were added to AD reactors, and AD efficiency and microbial composition were compared over one reaction cycle. The influence of biofilms was isolated by using glass beads with the same SSA. The study found that biochar with high SSA provides a stable colonization environment for microorganisms due to its rich porosity, but possesses fewer surface functional groups. Conversely, biochar with low SSA exhibited more surface functional groups. The increase in system electrical conductivity was primarily attributed to these functional groups, while the influence of microbial biofilms on DIET was minimal. These results highlight the potential of leveraging biochar's electrical conductivity in AD processes to enhance renewable energy production and waste management, providing significant implications for future applications using biochar to promote the DIET process in the AD of WAS.

Block rubber wastewater contains high levels of organic matter, sulfate, and ammonia. This study focused on optimizing the performance of an aerobic sequencing batch reactor (ASBR) for treating block rubber wastewater using indigenous microorganisms. The effects of organic loading rate (OLR) and initial mixed liquor volatile suspended solids (MLVSS) were evaluated. The optimal treatment was achieved at an OLR of 500 mg L^-1 day^-1 and an initial MLVSS of 3000 mg L^-1. Under this condition, the system removed 97.51% of chemical oxygen demand and 54.63% of sulfate. An integrated post-treatment filtration was applied, consisting of polypropylene, polyethylene, activated carbon, and anion exchange resin. The integrated ASBR and filtration process offers a sustainable solution for managing rubber wastewater in Southeast Asia, where rubber production is a key industry.

Nitroglycerin (NG), a recalcitrant and highly toxic nitroaromatic pollutant prevalent in wastewater from explosive manufacturing and pharmaceutical sectors, served as the target substrate for developing a synthetic microbial consortium through a bottom-up assembly strategy to enhance its biodegradation efficiency. Through statistical experimental design (DOE) and partial factorial approach (PFA), core strains (X10, X14, X71, X97, and X53) and non-core strains (X55, X88, and X58) were systematically identified. Subsequently, hierarchical stratification of core strains based on their degradation efficiencies toward nitroglycerin (NG) intermediate metabolites was implemented, while a comprehensive full factorial design of non-core strains, was conducted to establish structured microbial consortia X10 + X14 + X97 + X58. Response surface methodology (RSM) optimization identified 28°C, 140 rpm, 0.86 mM initial nitroglycerin (NG) concentration, 1:1:1:1 inoculation ratio, and simultaneous inoculation as the optimal parameters for achieving peak degradation efficiency (90.2 ± 0.8%). Biolog ECO-plate analysis has shown that the consortium can metabolize 31 different carbon sources. Through whole-genome sequencing and metatranscriptome analysis of enzyme genes related to nitroglycerin degradation, the speculation was that strains X10 and X14 were mainly responsible for the degradation of nitroglycerin (NG) to dinitro-glycerin (DNG) and further to mononitro-glycerin (MNG), while strains X97 and X58 were responsible for the degradation of mononitro-glycerin to glycerol, which constituted a complete nitroglycerin degradation pathway.

This study proposes an innovative process that aims to achieve the synergy of biogas purification and efficient nitrogen removal by introducing biogas into an Anammox reactor. In this process, high-purity methane (with a purity of up to 97.6%) is selectively extracted from biogas. Concurrently, the invigorating impact of biogas substantially diminishes the average size of sludge particles (from 0.73 to 0.65 mm), enhances mass transfer efficiency, and refines its physical and chemical characteristics, thereby augmenting the efficiency of nitrogen removal. When the nitrogen loading rate of the system reached 4880 mg N L^-1 day^-1, the total nitrogen removal amount reached 3200 mg N L^-1 day^-1. Microbial community analysis showed that Planctomycota was continuously enriched and dominated and Methylosarcina proliferated, confirming the promoting effect of biogas on changes in the anammox microbial system. This process offers an efficient and feasible technical pathway for mainstream anammox engineering by integrating biogas recycling and denitrification.

The chemical complexity of car wash water (CWW) treatment poses major technological and environmental challenges. This study reviews innovative low-cost composite material-based wastewater treatment techniques. The physicochemical properties of CWW, types of pollutants present, and volumes produced were examined to identify the primary treatment-related restrictions. The applications of adsorption, photocatalysis, and nanotechnology are detailed through experimental studies, presenting concrete results and discussing the advantages, challenges, and prospects for the improvement of these technologies. Innovation in digitizing and monitoring mobile modular treatment plants is also discussed, enabling better wastewater recovery and the optimization of measurement processes. The convergence of physicochemical and technological approaches, as illustrated by modular treatment units, is explored in depth. Hybrid composites and nanomaterials offer remarkable photocatalysis and adsorption, in addition to a significant reduction in organic loads and heavy metals. The combination of digital monitoring systems with movable modular stations renders the treatment process more sustainable and improves real-time control. The pilot deployment of these innovative solutions offers a complete panorama of recovery prospects, underlining the importance of integrating digital technologies for the sustainable, efficient, and optimized management of car wash water. This study provides a strategic framework that paves the way for future innovations and reinforces the commitment to responsible and sustainable environmental management.

With the increase in urbanization and industrialization, the environmental quality of river basins, which serve as a crucial source of irrigation for agricultural activities, has been deteriorating progressively. Thus, monitoring persistent toxic substances in urban water resources is crucial for maintaining ecological stability and protecting human health. In recent years, particular attention has been directed toward the prevention of polyaromatic hydrocarbons (PAHs), highlighting the importance of analyzing these compounds in water samples through more environmentally sustainable techniques. In this study, we report a green, rapid, cost-effective and simple dispersive liquid-liquid extraction (DLLME) method to monitor PAHs in river waters taken from 21 stations located within the geographical boundaries of the Gediz River Basin in Izmir Province, Türkiye. Methodological parameters were optimized by chemometric techniques including Plackett-Burman (PBD) and Box-Behnken design. The method's accuracy was tested upon spiked river samples, and the recoveries ranged from 80% to 102%. The calibration curves were linear, with correlation coefficients greater than 0.98. The limit of detection values were between 0.01 and 0.05 ng mL^-1. The reproducibility (RSD%) varied from 4.0% to 19%. Multivariate classification methods such as principal component analysis (PCA) and hierarchical cluster analysis (HCA), along with the supervised classification method partial least squares discriminant analysis (PLS-DA) were applied to elucidate the general distribution patterns of individual PAHs in the basin water samples. The chemometric evaluation conducted across four seasons revealed that PAH contamination was higher in the fall and winter months, resulting in a clear separation from spring and summer samples by using the first two principal components.

Emerging organic pollutants (EOPs), including per- and polyfluoroalkyl substances (PFAS), pharmaceuticals and personal care products (PPCPs), and pesticides are increasingly detected in various environmental compartments in Ethiopia, despite the limited industrial activity. These contaminants originate from the industrial parks, agricultural runoff, untreated wastewater from households and healthcare facilities, and unregulated pesticide use. This review provides recent findings on the occurrence, sources, and human health and ecological impacts of EOPs in Ethiopia. Elevated levels of PFAS and pharmaceutical residues have been reported in surface waters, sediments, and biota, particularly around urban centers and wastewater discharge points. Pesticide residues, including banned substances, are widespread in agricultural zones and water bodies, posing risks to human health and aquatic ecosystems. Regulatory action and pollution control measures have been characterized by a lack of coordination, even though the evidence indicates increased risk. The study also highlights significant gaps in monitoring capacity, regulatory enforcement, and public awareness. Innovative mitigation strategies such as nature-based solutions, advanced oxidation processes, and the development of low-cost adsorbents from local materials are discussed as promising interventions. The paper underscores the need for integrated policies, enhanced scientific infrastructure, and cross-sectoral collaboration to manage EOPs effectively. While challenges remain, a context-specific and coordinated approach offers a sustainable path forward to safeguard public health and environmental integrity in Ethiopia.

In the present work, focused on augmenting the freshwater yield, thermal and exergy efficiencies, economic and environmental feasibility in the tubular solar still (TSS) with the help of utilizing an agricultural biowaste material like pistachio shell material, and carbonized black powder of pistachio shell material. Despite comprehensive work on solar desalination utilizing biowaste materials, the potential application of carbonized pistachio shell materials has not been explored for solar distillation. This study addresses the gap in the utilization of biowaste materials and demonstrates how utilizing biowaste-derived materials can provide freshwater while contributing to sustainable waste management. Three different stills-TSS, TSS with pistachio shell powder (PS), and TSS with pistachio shell carbon black (PSCB)-were investigated in the current work and examined under atmospheric conditions. The pistachio shell material is carbonized at 120°C for 12 h in a vacuum oven to obtain a carbon black powder for use in TSS to improve high water productivity. The modified tubular solar still (MTSS) operated similarly to a conventional TSS. The experiments were conducted in similar meteorological conditions. The daily yield productivities of the MTSS of PS powder and PSCB powder were about 3.4 and 4.1 kg/m², respectively, whereas the conventional TSS produced a daily productivity of 2.9 kg/m². It lead to an augmentation of 43.5% for the MTSS with PSCB and 17.24% for the TSS with the pure PS powder over the CTSS model.

In this study, septage wastewater treatment using the flocculation/coagulation process by the natural coagulant Ocimum basilicum L. (basil) and chemical coagulants polyaluminum chloride (PAC), ferric chloride, and alum was studied. Under different conditions, the extraction of the seed of O. basilicum was done by maceration method, and SPSS 23 software was used to identify the most effective extract and chemical coagulant. The effects of five parameters-pH, coagulant dose, coagulant aid dose, rapid mixing time, and slow mixing time-on the reduction of COD, TSS, NH₄, and TP in septage samples were examined by conducting the Central Composite Design (CCD). Optimum conditions predicted by the response surface models were determined at pH 4.00, coagulant dose 498.50 mg/L, rapid mixing time 5.00 min, slow mixing time 21.60 min for natural coagulant, and pH 4.01, coagulant dose 372.88 mg/L, and coagulant aid dose 1.55 mg/L for chemical coagulant (PAC). Under optimal conditions, the reduction percentages of COD, TSS, NH₄, and TP parameters were 64.40, 87.30, 70.56, and 71.92 for natural coagulant, and 65.30, 73.42, 71.12, and 74.68 for chemical coagulant (PAC).