Water Environment Research最新文献

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).

The pollutant removal pathways and the influencing catalysts have been assessed in benthic sediment and emergent plants-based two electroactive surface flow (SF) wetlands operated under variable wastewater contact and treated strong wastewater, that is, landfill leachate. The two SF systems achieved mean removal percentages of 68%-81% for organic matter, 33%-52% for nitrogen, 42%-70% for phosphorus, and 31%-84% for coliforms, respectively. The positive impact of electrogenic bioreactions on the removal routes in the reductive environment-dominated anode compartment, as well as the supplementary contribution from the cathode zone, improved overall organic, phosphorus, and coliform removals in the closed circuit-based (with external resistance) SF wetland. The open circuit-based SF wetland (without external resistance) achieved better nitrogen removal due to the availability of oxygen as an electron acceptor for oxidizing NH₄-N, particularly in the anode compartment. A higher wastewater contact period improved the organic removal in both systems, supporting both physicochemical and microbial-based routes. However, it also triggered oxygen consumption by the aerobic-based organic removal pathways, thereby restricting nitrification in the cathode compartments. The higher phosphorus composition of the benthic stone dust than the fresh (i.e., before being utilized as the benthic sediment) samples reflects the effect of the chemical route-based adsorption route. The mean voltage production within the two systems ranged from 50 to 215 mV; the bioenergy and wastewater contact period increments showed a positive correlation in both systems. This study investigated the interactions among benthic sediment, plants, electrodes, circuit connections, and wastewater pollutants in electrode-coupled SF wetlands operated under variable wastewater contact periods and higher influent organic strength.

On-demand purified water dispensers have been widely installed in residential communities (RCs) in China. However, water stagnation and the absence of chlorine disinfectants in these dispensers can lead to significant microbiological risks. To clarify these risks in purified water, in this study, the characteristics of the microbial community and associated microbiological hazards in 40 purified water samples from on-demand purified water dispensers in four administrative districts were investigated using quantitative PCR (qPCR) and high-throughput sequencing methods. The results revealed that the turbidity of the purified water was generally very low (< 0.28 NTU), but chlorine disinfectant was detected in more than half of the samples, indicating failure of the activated carbon process within the dispensers. Culturable bacterial counts revealed high levels of culturable bacteria in the collected water samples. Furthermore, the bacterial 16S rRNA gene copy number reached up to 6.23 Log10 Gene copies/mL. Among the seven pathogenic microorganisms detected by qPCR, Mycobacterium (95%) and Legionella (82.5%) were commonly detected with high biomass. The average gene copy number for Mycobacterium was 3.08 Log10 Gene copies/mL (0.30-4.33 Log10 Gene copies/mL), and for Legionella, it was 2.96 Log10 Gene copies/mL (0.38-4.05 Log10 Gene copies/mL). High-throughput sequencing revealed that 17 out of the top 50 microbial taxa detected at the genus level might be potential pathogens. This study demonstrates that drinking water from on-demand purified water dispensers in residential communities is associated with increased microbiological risk, necessitating enhanced monitoring and regulatory oversight.