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Enhancing nitrogen removal is a very active branch in municipal wastewater treatment research, toward this end, anammox technology is a sustainable solution. This review systematically outlines the strategies employed to enhance mainstream anammox performance, including nitrite accumulation and microbial enrichment based on partial nitrification coupled anammox and partial denitrification coupled anammox, developed to address the challenges of low ammonium content in wastewater, nitrate accumulation in the effluent, and the influence of organic matter. The characteristics and advantages of novel anammox-coupled processes, including partial nitrification and partial denitrification coupled anammox, endogenous partial denitrification coupled anammox, and denitrifying anaerobic methane oxic coupled anammox are also comprehensively discussed; these aim to ensure the highly efficient and stable operation of anammox under diverse wastewater conditions by constructing a composite biological nitrogen removal system based on anammox, supplemented by nitrification-denitrification and other processes. Additionally, a novel anammox application route including mainstream partial denitrification/anammox and absorptionbiodegradation as well as sidestream partial nitrification/anammox is proposed, and its application pathway in conceptual wastewater treatment plants is outlined, aiming to foster the development of cost-effective, efficient, and energy-saving advanced wastewater treatment processes. Finally, prospects are presented that indicate the gaps in contemporary research and potential future research directions. Overall, this review provides a reference for treating municipal wastewater with anammox and sheds new light on related strategies and nitrogen removal mechanisms. [ABSTRACT FROM AUTHOR]

The safe use of wastewater in irrigation practices in developing countries, and especially regions with water shortages, is an issue of concern for policymakers and society at large as the unsafe use of treated or semi-treated wastewater can pose potential risks to the environment, the safety of agricultural products and ultimately food safety. The implementation of supplementary parameters surrounding irrigation conditions with treated or semi-treated wastewater at the farm level depends on the behaviours of farmers, with psychological factors coming into play. Furthermore, accurate intervention strategies can guide farmers towards the safe usage of wastewater for irrigation. In this study, we have used survey data from Mashhad County in Iran to test the components of the theory of planned behaviour, including the effects of two intervention strategies, namely government enforcement and cooperative involvement, on farmers' safety behaviours when it comes to using semi-treated wastewater for irrigation practices. Structural equation modelling was employed for the analysis. The results show that the three key components of the theory of planned behaviour, that is attitude, subjective norms, and perceived behavioural control, have a significant impact on the intentions of farmers to engage in the safe use of semi-treated wastewater for irrigation. Additionally, cooperative involvement is more effective for the farmers than government enforcement. This suggests that there should be an increase in the official support available for agricultural cooperatives that operate as wastewater collectives. [ABSTRACT FROM AUTHOR]

Developing countries still lag in transitioning wastewater treatment plants towards resource recovery. This study assessed the challenges hindering and opportunities enabling the implementation of resource recovery from municipal wastewater treatment in Zvishavane town, Zimbabwe using the descriptive case study research design to collect data from selected key informant interviewees. Findings highlighted that resource recovery from Zvishavane's Mabula wastewater treatment plant was at a nascent but dormant stage. Policy, economic, technological factors and lack of expertise were identified as limiting the transition towards resource recovery in Zvishavane. On the other hand, findings indicated that several enabling factors could enable the transition of the Mabula wastewater treatment plant into a resource recovery facility. These included the presence of entrepreneurs working in the resource recovery sector, university-utility collaboration and a vast raw material base. A stakeholder interaction model was developed to create pathways towards resource recovery in Zvishavane. [ABSTRACT FROM AUTHOR]

The anaerobic baffled reactor (ABR) is a decentralized treatment system that is commonly used for municipal wastewater treatment. Slower growth rate of anaerobic microorganisms requires extended hydraulic retention time (HRT), leading to a larger bioreactor volume. In this study, polyurethane sponge sheets were provided in a six-compartment ABR for retention and growth of biomass to improve its treatment performance at shorter HRTs. Polyurethane sponge was selected for its low cost, durability, availability, easy emplacement, and high voidage. The sponge anaerobic baffled reactor (SABR) was operated within a temperature range of 35 ± 1 °C at HRTs of 18, 12, 8, and 6 h to evaluate its treatment performance. Average removal efficiencies ranged from 60–77% for organics, 74–81% for total suspended solids (TSS), 50–66% for total nitrogen (TN), and 47–57% for total phosphorus (TP). The shortest HRT was 8 h with average removal efficiencies of 74, 63, 64, and 52% for organics, TSS, TN, and TP, respectively, to meet effluent discharge limits. With the shortest HRT of 8 h, the SABR demonstrated low volume requirements, thereby making it an efficient solution for decentralized wastewater treatment, particularly advantageous for developing countries with warm climates. [ABSTRACT FROM AUTHOR]

The European Parliament adopted a legislative resolution of 10 April 2024 on the proposal for a directive of the European Parliament and of the Council concerning urban wastewater treatment. The reduction in pollution in discharged treated wastewater in the parameters of BOD5, total nitrogen, and total phosphorus was emphasized. Based on these results, it stated that the impacts on the quality of lakes, rivers, and seas in the EU are visible and tangible. At the same time, it was emphasized that the sector of urban wastewater removal and treatment is responsible for 0.8% of total electricity consumption and about 0.86% of all greenhouse gas emissions in the entire EU. Almost a third of these emissions could be prevented by improving the treatment process, better use of sewage sludge, and increasing energy efficiency, as well as a higher rate of use of renewable resource technologies. It is also necessary to integrate treatment processes into the circular economy. Sludge management and water reuse are suboptimal as too many valuable resources are still being wasted. This article focuses on sustainable municipal wastewater treatment, innovative and new wastewater treatment processes and technologies (combined and hybrid processes, ANAMMOX, etc.) and their use in practice with the aim of increasing environmental and energy efficiency and reducing the carbon footprint. The research is focused on the possibilities of increasing the efficiency of energy processing of sludge, reuse of nitrogen and phosphorus, sludge, and reuse of treated wastewater. [ABSTRACT FROM AUTHOR]

In this study, a multi-functional layer was developed based on the commercially available cellulose triacetate (CTA) forward osmosis (FO) membrane to improve its antifouling property. Tannic acid/ferric ion (TA/Fe3+) complexes were firstly coated as a precursor layer on the membrane surface via self-assembly. Afterwards, the tannic acid/diethylenetriamine (TA/DETA) hydrophilic functional layer was further coated, following Ag/polyvinylpyrrolidone (PVP) anti-bacterial layer was formed in situ through the reducibility of TA to obtain TA/Fe3+-TA/DETA-Ag/PVP-modified membrane. The optimized precursor layer was acquired by adjusting the buffer solution pH to 8, TA/Fe3+ ratio to 4 and the number of self-assembled layers to 5. The permeability testing results illustrated that the functional layer had an insignificant effect on the membrane transport parameters. The TA/Fe3+-TA/DETA-Ag/PVP-modified membrane simultaneously exhibited excellent physical and chemical stability. The coated membrane also demonstrated enhanced anti-bacterial properties, achieving 98.63 and 97.30% inhibition against Staphylococcus aureus and Escherichia coli, respectively. Furthermore, the dynamic fouling experiment showed a 12% higher water flux decrease for the TA/Fe3+-TA/DETA-Ag/PVP CTA membrane compared to the nascent CTA membrane, which proved its excellent antifouling performance. This work provides a feasible strategy to heighten the antifouling property of the CTA FO membrane. HIGHLIGHTS Surface modification of CTA FO through TA/Fe3+ and TA/DETA coating layers and in situ reduction of Ag.; The multi-functional layer had no considerable impact on the mass transport coefficients of the CTA FO membrane.; The antifouling of the modified membrane was remarkably improved for raw municipal wastewater treatment.;

This study aims to optimize the removal of carbon and nitrogen pollutants from saline municipal wastewater using both membrane-based and biological treatment methods. It examines a pilot-scale sequential aerobic ceramic membrane bioreactor (AeCMBR) under various salinity levels (0–20 g NaCl/L) to assess biological processes and fouling behavior. While high COD removal rates of (≈90%) were consistently achieved, ammoniacal nitrogen removal dropped from 82 to 55% at 15 g NaCl/L, despite increased oxygenation flow rates. Notably, the biomass quickly adapted to salinity changes. Indicators such as mixed liquor suspended solids (MLSS), mixed liquor suspended volatiles (MLVSS), MLVSS/MLSS ratio, and sludge volume index (SVI) showed no significant correlation with increasing salt concentrations. Soluble microbial product (SMP) production was also unaffected by rising salinity levels. The transmembrane pressure (TMP) fluctuated, with the most pronounced trend at 15 g NaCl/L, even after reducing the flux from 20 to 15 L/m2/h. The primary fouling mechanism observed was reversible cake deposition. Overall, this research enhances our understanding of short-term operational impacts on AeCMBR performance as a function of different salinity levels. HIGHLIGHTS We investigated an AeCMBR pilot plant-treated wastewater with rising salinity.; Reversible cake deposition fouled the membrane consistently.; Graduated salinity had no consistent impact on treatment efficiency.; Nitrifiers can handle up to 15 g/L NaCl with proper aeration.; Complex municipal wastewater needs thorough homogenization.; The study offers valuable control and operation insights for practitioners.;

In this study, a facile method for multifunctional surface modification on forward osmosis (FO) membrane was constructed by surface immobilization of AgNPs based on tannic acid (TA)/diethylenetriamine (DETA) precursor layer. The cellulose triacetate (CTA) FO membranes modified by TA and DETA with different co-deposition time (6 h, 12 h, 24 h) were investigated. Results indicated that the TA/DETA (24)-Ag CTA membrane with a TA/DETA co-deposition time of 24 h was identified to be optimal, which attained more hydrophilic. And it had the bacterial mortality of Escherichia coli and Staphylococcus aureus reaching 98.23% and 99.83% respectively and possessed excellent physical and chemical binding stability. Meanwhile, the coating layer resulted in the antifouling ability without damaging the membrane intrinsic transport characteristics. As for synthetic municipal wastewater treatment, the water flux of CTA FO membrane decreased approximately 49% of the initial flux after running for 14 days. In contrast, the flux decline rate of TA/DETA (24)-Ag CTA membrane was about 37%. Furthermore, less foulant deposition and higher recovery rate of water flux was observed for TA/DETA (24)-Ag CTA membrane, implying that the modified membrane effectively alleviated membrane fouling and processed a lower flux decline during municipal wastewater treatment. It was attributed to the enhanced surface hydrophilicity and antibacterial property of the coating layer, which improved antifouling property. [ABSTRACT FROM AUTHOR]

Wastewater treatment is now required because of the problems caused by water constraints. Wastewater is anaerobically digested to produce biogas, which can be used as a source of energy for things like lighting and heating. The upflow anaerobic sludge blanket (UASB) reactor has been recognized as an important wastewater treatment technology among anaerobic treatment methods. Although their treated effluent typically does not meet most discharge criteria, UASB reactors are generally stated to have a chemical oxygen demand (COD) reduction ranging from 60 to 90% for most types of wastewater. In comparison to traditional anaerobic procedures, anaerobic municipal wastewater treatment using membranes can produce higher effluent quality in terms of COD, suspended solids (SSs) and pathogen counts, as well as a steady treatment performance to fulfill strict discharge regulations. The objective of this review was to perform a literature review on parameters to consider when selecting a membrane to include in a UASB reactor. Membranes that are available in the market were compared in terms of both physical and chemical properties. Polyvinylidene fluoride (PVDF) membranes were found be superior to the others, and their modification also reduced the fouling propensity. When comparing modified PVDF (PVDF/PVDF-g-PEGMA) to pristine PVDF (116 L·m−2 h−1), a higher pure water flux (5170 L·m−2 h−1) was noted. The main drawback of such modifications could significantly increase the final membrane production costs. Research is still lacking when it comes to research on comparing the membranes and PVDF and UASB reactor technology interaction, including effects of its modification as discussed (stability, longevity of improved flux, etc. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Beijing University of Technology is the property of Journal of Beijing University of Technology, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The study examined prefermentation of primary sludge in an up-flow settler/prefermenter model to enrich wastewater with biodegradable substrate for denitrification. The experiment, preceded by batch tests, was conducted under real conditions in a municipal wastewater treatment plant. The effect of solid retention time (SRT) was the focus while other parameters, such as hydraulic retention time and up-flow velocity, remained constant. The efficiency of chemical oxygen demand (COD) solubilisation and improvement of denitrification potential increased as the SRT increased from 1 to 5 d. At 5 d SRT, dissolved COD and denitrification potential increased by 56 mg/L and 7.6 mg·N–NOx/L, respectively, corresponding to 35% and 36% of the influent values. However, the onset of intensive biogas production occurred at SRT of 7 d, hindering sludge sedimentation and preventing achievement of a longer SRT. [ABSTRACT FROM AUTHOR]

To verify the feasibility of biofilm-membrane bioreactor in municipal wastewater treatment. In this paper, based on the Fourier series algorithm, the basic configuration of biofilm-membrane bioreactor, the design of membrane bioreactor test index and method, the proposed urban wastewater treatment system based on biofilm-membrane bioreactor, and the creation of experiments to verify the biofilm-membrane bioreactor with the example of urban wastewater in the sewer of residential buildings in the district on the two CODCr and NH4+-N in urban wastewater in municipal wastewater. The results showed that the removal rate of CODCr in municipal wastewater by the biofilm-membrane bioreactor system increased with time, and the removal rate was stable at about 83%. The NH4+-N removal rate increased with time and was stable between 85 and 90%. It can be shown that biofilm-membrane bioreactor can sufficiently reduce the concentration of CODCr and NH4+-N in municipal wastewater, thus promoting municipal wastewater treatment. It also presents a new solution for urban wastewater treatment.

In recent years, there has been an increase in the interest on organic compounds originating from anthropogenic activities. The presence of these micropollutants in waterbodies can be detrimental for the aquatic organisms even at their trace concentrations. Removal of micropollutants from wastewater by conventional treatment methods is quite limited, thereby existing wastewater treatment plants are not capable of removing these micropollutants. This study investigated the removal of 27 micropollutants and conventional pollution parameters by ozonation of the effluent from a pilot-scale high-rate activated sludge system treating municipal wastewater. Different ozone dosages and contact times were tested during the study. Results revealed that 7 out of 27 micropollutants were detected in the effluent. Over 45% chemical oxygen demand (COD) removal and over 65% total suspended solids (TSS) removal were achieved by the ozonation process. Among the various ozone dosage and contact time combinations investigated in the study; 6 mg/L ozone dosage-20 min contact time, and 9 mg/L ozone dosage-10 min contact time alternatives resulted with the best treatment performance in terms of the removal of micropollutants, COD, TSS, and turbidity. A feasibility analysis was conducted to evaluate the best operational conditions from a techno-economic perspective and the results revealed that the unit cost for ozonation process ranged between 0.033 $/m3 and 0.043 $/m3. Additionally, considering the feasibility, 6 mg/L ozone dose – 20 min contact time combination was found as the optimum alternative. Based on the promising results obtained in this study, ozonation can be offered as a polishing step for the effluents of high-rate activated sludge systems for the improving of the effluent quality. [ABSTRACT FROM AUTHOR]

In this work, we demonstrate the surface functionalization of cellulose triacetate membrane with co-deposition of polydopamine (PDA)/polyethyleneimine (PEI) and silver nanoparticles (AgNPs) for antifouling property in municipal wastewater treatment. PDA/PEI was first coated on the membrane surface by single-step co-deposition, while AgNPs were formed in situ through catechol groups of PDA immobilizing silver ions and subsequently reducing. The successful surface modification was verified by different membrane characterization techniques. The modified PDA/PEI-nAg CTA membrane exhibits enhanced hydrophilicity and improved antiadhesion and antimicrobial activity. Furthermore, the functional layer had an indistinctive effect on the membrane transport parameters. In addition, dynamic forward osmosis (FO) fouling experiment with raw municipal wastewater as feed solution indicated that the PDA/PEI-nAg CTA membrane exhibited notably lower water flux decrease compared to the nascent CTA membrane. The results of confocal laser scanning microscopy (CLSM) showed that PDA/PEI-nAg CTA membranes effectively reduced the adsorption of organic foulants (proteins and polysaccharides) and inhibited the formation and development of the fouling layer. The membrane surface modification of the CTA membrane with PDA/PEI and AgNPs efficiently mitigated membrane fouling in municipal wastewater treatment. HIGHLIGHTS AgNPs were in situ immobilized on a CTA FO membrane with PDA/PEI coating layer.; The PDA/PEI coating and Ag in situ generation had no considerable impact on the mass transport coefficients of the CTA FO membrane.; The PDA/PEI-nAg CTA-modified membrane exhibited excellent antifouling performance for raw municipal wastewater treatment.;

With population and economy growth, water usage, wastewater generation and treatment, treatment plants capacity and innovation ability in Iran have increased dramatically in the last decades. Currently, Iran is in the grip of severe water scarcity, with renewable water availability of less than 1700 m3/capita/y. Total municipal wastewater generated in Iran is 4.61 billion m3/y out of which only 42% is treated. The conventional activated sludge process accounted for the largest share (> 60%) in municipal wastewater treatment in Iran. The treatment plants operational costs usually amount up to 0.2 US $/m3 wastewater. About 55% of treated municipal effluent is reused in Iran, with an emphasis on the agricultural sector. The electricity consumption in municipal wastewater treatment facilities amounts for 0.1% (241 million kWh/y) of the total electricity consumption of the country. Meanwhile, the current laws and policies are sometimes inefficient or do not prompt the ideal outcomes. Thus, the present study provides an overview of municipal wastewater treatment in Iran by describing the current situation and collecting data from 68 treatment plants, and defining key barriers and future policies needs towards Iran’s sustainable municipal wastewater management (up to 2040). Here, the opinions of 50 experts from the governmental sector, industry division, and faculty members were surveyed through the meetings of the technical and steering committee. Overall, sustainable municipal wastewater management in Iran would be obtained by developing water resources, increasing the population covered by wastewater facilities (90%), improving effluent discharge standards, and lowering energy usage to 0.45 kWh/m3 wastewater.

Sewage sludge management at wastewater treatment plants is becoming a more and more challenging task. Here, an innovative integrated modeling approach is developed to investigate the optimization of a municipal wastewater treatment plant (MWWTP) by the inclusion of hydrothermal carbonization (HTC). To this aim, two alternative plant layouts have been considered: (i) a conventional activated sludge-based treatment plant, i.e., based on thickening, stabilization, conditioning, and dewatering; (ii) additional hydrothermal carbonization and integrated treatment of the spent liquor in the sludge line. An Italian MWWTP has been selected as a case study, and three different scenarios have been implemented in the process simulation software World Wide Engine for Simulation Training and Automation (WEST) by considering the effect of the different digestion times in the aerobic reactor. Then, according to the Design of Experiment (DoE) methodology applied both on simulated and experimental data, and by the use of a Python code, the desired models have been developed and compared. Finally, a Life Cycle Assessment (LCA) study has been carried out to estimate the impacts on human health, ecosystems, and resources. The integration of HTC corresponds to the generation of a valuable product (the hydrochar), whereas the conventional layout is associated with high disposal costs of the sewage sludge. According to LCA results, a sludge age of 40 days is recommended due to the lowest impacts estimated, both with and without a HTC section. This has been ascribed mainly to the electricity demand of the sludge line, which increases with the excess sludge flow rate, i.e., as the sludge age decreases. [ABSTRACT FROM AUTHOR]

During an iron-electrocoagulation (Fe-EC) process, floc formation is essential for achieving high contaminants removal. Thus, the complete oxidation of the Fe2+ dosed as coagulant is a critical step for ferric oxides flocs formation. Since the fluctuation in the quality of the influent wastewater affects the kinetics of Fe2+ oxidation, the estimation of optimal operating conditions (i.e. the retention time, dissolved oxygen (DO) concentration, etc.) for high Fe2+ oxidation is required. In this study, the kinetics of Fe2+ oxidation was simulated using PHREEQC software by theoretically optimizing, validating and improving the previously published kinetic models. During model simulation, the process parameters were varied from low to high ranges: Fe2+ dosage (10–100 mg/L) and retention times under the influence of changing pH (7.5–8.2), temperature (12–22 °C), alkalinity (5–10 mEq/L) and initial DO (8.6–10.5 mg/L). Fe2+ oxidation rate was more affected by pH variations in the influent than by temperature variations. A pH increase (+0.4 to +1.7 pH units) was observed due to the low wastewater alkalinity, promoting high Fe2+ oxidation rates. To ensure optimum Fe2+ oxidation levels (≥98%), a minimum retention time of 20 minutes was estimated. Finally, the residual DO concentration should be >3.5 mg/L to avoid a decrease in the oxidation rate. This study contributes to the ongoing research in the field of physico-chemical wastewater treatment with EC by establishing the optimal process parameters required for system optimization and process scalability. HIGHLIGHTS PHREEQC software was used to model Fe2+ oxidation kinetics in a Fe-EC system.; The formation of OH- during the EC process increases the Fe2+ oxidation rate.; Low oxygen content is a critical parameter for EC applications in wastewater.; The residual DO should be >3.5 mg/L to avoid a decrease in the oxidation rate.; A minimum retention time of 20 minutes is need for achieving ≥98% of Fe2+ oxidation.;

This study investigated two different hybrid processes for the treatment of municipal secondary-treated biological effluents to meet the reuse of recycled water requirements for organic matter and color. The two hybrid treatment approaches were an oxidation-based treatment process (coagulation–sedimentation–deep-bed filtration [CSDF]–ozone oxidation) and an adsorption-based treatment process (CSDF-granular activated carbon [GAC] adsorption). The efficiencies of ozonation and GAC adsorption in removing chemical organic demand (COD), dissolved organic carbon (DOC), and color intensity were evaluated. The effect of CSDF as the pretreatment was also studied. Ozonation showed a much higher color removal efficiency (88%, 4.7 mg/L ozone dose) than GAC adsorption (23%). Organic matter with an apparent molecular weight of 2–3 kDa, being humus-like, might be the colored fraction in the secondary and CSDF effluents. Ozonation had a stronger ability to remove these substances than GAC adsorption, resulting in a visibly higher color removal efficiency. In addition, higher COD and DOC removal were achieved by ozonation when the average ozone dose was increased to 9.1 mg/L. Although both hybrid processes were reliable for reducing organic matter and color, the results show that ozonation is more suitable for simultaneously removing refractory organic matter and color. [ABSTRACT FROM AUTHOR]

Copyright of Environmental Science & Technology (10036504) is the property of Editorial Board of Environmental Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The biological fouling in polymer membranes is one of the main challenges in the membrane processes. Accordingly, CuO nanomaterials with properties such as high resistance to physical, chemical, biological agents, as well as antibacterial properties can be considered as one of the effective additives in the fabrication of composite ultrafiltration membranes, and reduce biological fouling. In this study, PVDF (16wt %), PVP (1wt %), CuO nano-plates (1wt %) were used in fabrication membranes (Phase inversion method) to increase hydrophilic properties, to reduce the membrane fouling and improve the ultrafiltration membrane filteration performance. The physical and chemical characterization of CuO nano-plates (synthesized by hydrothermal method) and fabricated membranes evaluated by XRD and FTIR analysis and also FESEM and TEM were used to study the morphology of the samples. The mixture of CuO nanoparticles with the semi-crystalline polymer structure of PVDF improved the β phase in the membrane structure which improved the hydrophilic properties of the membrane feature. The results showed that the flux and rejection of CuO nanocomposite membranes were 357 and 96% LMH, respectively, and the contact angle was about 59 degrees, which increased the hydrophilic properties of the surface by 25% compared to the control sample. The recovery rate of CuO nanocomposite membrane was about 83%, which indicates the effect of antibacterial properties of these nano-plates. Finally, BSA solution and municipal wastewater were used to evaluate the performance of nanocomposite membrane in filtration and purification. PVDF/CuO composite membrane had high efficiency in disinfection and wastewater treatment; The COD of the treated effluent was less than 5 mg/L and the removal of turbidity and TSS was about 99% and no fecal coliforms were detected.

Wastewater management remains a major challenge in developing countries due to the lack of adequate infrastructure, making the need for economically viable and efficient technologies that can be sustained by emerging economies imperative. The upflow anaerobic sludge blanket (UASB) reactor represents an efficient and low-cost technology that produces by-products from which valuable resources can be recovered. This study assessed the energy recovery potential in the form of electricity from biogas and sludge by-products produced by a full-scale UASB reactor. Biogas production rate and composition were monitored to determine the biogas energy recovery potential. Dehydrated sludge from sludge drying beds was likewise quantified and characterised for its elemental composition, immediate composition, gross calorific value and net calorific value to estimate sludge energy recovery potential. The average daily biogas production was found to be 611 ± 275 Nm3/d, with 65% methane in the biogas output. Average sludge dry matter production was determined to be 358.24 TS kg/d. The net energy recovery potential was estimated to be 534.1 MWh/yr, 36% more than the yearly energy demand (392.7 MWh/yr) of the entire plant. Conservative energy recovery at a UASB-based municipal wastewater treatment facility could serve as a self-supply energy option to support its operations. [ABSTRACT FROM AUTHOR]

Wastewater treatment technologies (WWTTs) are employed across the world, and the selection is mainly based on 'past experiences' aimed at 'pollution prevention' in the receiving water bodies. This paper aims to develop a methodology for the selection of an appropriate wastewater treatment chain that produces effluent suitable for the defined reuse. Adopting the least weighted cost approach, four decision criteria: Capital cost, Operation and Maintenance cost, Land requirement, and Energy requirement, have been used and the Full Consistency Method (FUCOM) has been employed for obtaining weights. Quality expectations for 14 reuses have been enlisted, and 25 WWTTs have been evaluated in a total of 360 combinations. In Kanpur city, for water reuse in industrial cooling under restricted land and challenging influent quality conditions, a combination of Membrane Bioreactor (MBR) with Wuhrmann process (WP) is obtained as the most preferred suggestion. For non-potable domestic reuse, Anaerobic Anoxic Oxic (A2O) with Ultrafiltration (UF) and Reverse Osmosis (RO) is the most preferred combination. In Varanasi city, for vehicular washing operations and for flow augmentation (inland surface water), under energy-constraint scenario, high-rate activated sludge-based biological filtration and oxygenated reactor (BIOFOR-F) is suggested. For technology supplementation to existing ASP-based STPs in the city to obtain effluent for inland surface water augmentation, WP in combination with microfiltration (MF) and reverse osmosis (RO) is suggested. Thus, the developed model may be used as a decision-making tool for planning a reuse-focused water reclamation program or for upgradation of existing STPs as per resource availability and target reuse objectives. [ABSTRACT FROM AUTHOR]

The utilization of hybrid-constructed wetland systems has recently expanded due to more rigorous municipal wastewater discharge and also complex wastewaters treated in hybrid-constructed wetlands (HCWs). A lab-scale two-stage experimental setup of vertical flow followed by horizontal flow hybrid-constructed wetland (VFHCW-HFHCW) configuration was built. First-stage vertical flow hybrid-constructed wetland reactor with the surface area was 1963.49 cm2 and second-stage horizontal flow hybrid-constructed wetland reactor with the surface area was 2025 cm2. The HCW unit was planted with two type plants: Calibanus hookeri and Canna indica (Cannaceae). Influent Municipal wastewater flow rate 112.32 l/day, hydraulic loading rate (HLR) 0.55 m/day, and hydraulic retention time of 1 day. The efficiency was evaluated in municipal wastewater quality improvement and physico-chemical analysis in our laboratory. The removal rate after the second-stage horizontal flow of BOD3 at 27 °C, COD, TSS, TP, NH3-N, and NO3-N reached 92.75%, 89.90%, 85.45%, 88.83%, 99.09%, and 96.05%, respectively. The results shown after both stage hybrid-constructed wetland VFHCW-HFHCW, treated effluent of Municipal wastewater produced high-quality effluent which may be reused in gardening, agriculture, and flushing in toilet purpose according to Bureau of Indian Standards (BIS) code for practices. However, in the future, hybrid-constructed wetlands could be standards design criteria developing and enhancing the performance standards and economic meets both to make more popular technology of the hybrid-constructed wetland (HCW). [ABSTRACT FROM AUTHOR]

Anaerobic membrane bioreactor (AnMBR) is one of the most advanced water treatment technologies that might contribute to overcome exponential water demand in many regions around the world. AnMBR technology converts wastewater (WW) to reasonable quality of permeate water which can be used for irrigation, produces energy in the form of biogas, and generates stabilized sludge that can be recovered as biofertilizer. In the last decade, AnMBR got high interest to be used for municipal wastewater (MWW) treatment. However, AnMBR still faces some issues that hinder its upscaling to industrial maturity. This review focuses on improving the performance of AnMBR with respect to system configuration and design aspects. Both the fundamental biological (anaerobic digestion) and physical (membrane filtration mechanisms) treatment are discussed. The effect of operational parameters on the performance of AnMBR and exploitation challenges (such as fouling) of AnMBR are addressed as well. Overall, new research directions aiming at improving AnMBR performance (strategies to ensure stability under different organic loads and operating conditions, maximum recovery of dissolved methane, combination of different cleaning techniques, validation of the economic feasibility on a large scale) is still needed.

Industrialization and urbanization have resulted in large volumes of municipal wastewater containing abundant refractory humic acid (HA), which is difficult to biodegrade with carcinogenic byproducts and has posed a great threat to human health. Photocatalysis is a promising advanced oxidation process (AOP) for the efficient degradation of HA. In this work, a novel three-step electrochemical method was employed to fabricate electrochemically converted N-doped TiO2 nanotubes/graphene (ENTG) composite film. Compared with traditional hydrothermally synthesized N-doped TiO2/graphene (NTG) nanoparticles, the ENTG photocatalyst exhibited enhanced degradation performance, recyclability and stability. It was found that ETNG can extend the range of light absorption to over 400 nm and narrow the band gap to 2.7 eV. The degradation rate for HA was up to 92.3% under the optimum condition. The preparation mechanism for ENTG is based on an electrochemical reduction–deposition hypothesis, while the degradation mechanism is dependent on adsorption and free radical oxidation. According to a free radical quenching test, both •OH and •O2− radicals were produced, and •OH played the dominant role in HA degradation. In general, ENTG is a promising photocatalyst for further application in municipal wastewater treatment. [ABSTRACT FROM AUTHOR]

The reuse of treated wastewater in countries such as Iran that suffers from drought is considered an important challenge in water management programs. The application of modern wastewater treatment systems particularly attached growth systems, owing to the short time required for start-up, low land requirements, and the absence of problems associated with sludge handling may be a resolution. The objective of this study is to investigate the performance of the Moving Bed Biofilm Reactor (MBBR) in treating synthetic municipal wastewater and selecting an appropriate model. In this way, a bench-scale reactor possessing an effective volume of 15 liters, and synthetic wastewater with influent COD of 500 mg/l (similar to typical municipal wastewater) has been used and the experiments with media filling percentages of 30%, 50%, and 70% and hydraulic retention times (HRT) of 4, 8, and 12 hours have been carried out. The observed data show that the optimum bulk density and hydraulic retention time are 50% and 4 hours, respectively. Also, the kinetic study of reactor performance indicates that Grau second-order model has better conformation with Moving Bed Biofilm Reactor results. In addition, a regression model for predicting effluent COD based on the filling percentage and retention time is presented.

Abstract Background and Aim: Increasing wastewater production and increasing waste production are major threats to human health and the environment; therefore, wastewater treatment and waste reuse should be done. This study aimed to determine the efficiency of plastic, rubber, and electronic wastes for municipal wastewater treatment by the microbial electrochemical method. Materials and methods: This experimental-practical research was done on a pilot scale. Impacts of time and initial characteristics (temperature, pH, and EC) on the treatment efficiency were investigated. During the research, sampling (twice a week) was done from the input and output of the reactor, and BOD , COD, TSS, pH, and EC parameters were measured according to the standard methods. The results were analyzed by Excel 2010 software. Results: Mean BOD 5 , COD, and TSS in raw sewage were 227, 302, and 274 mg/l. BOD5 removal efficiencies by electronic, rubber, plastic and control wastes were 72.46, 69.74, 60.82, and 62.17%, respectively. Electronic wastes with 55.52% and 79.96% had the highest removal efficiencies of TSS and COD, respectively. Conclusion: Bed material affects BOD 5 removal efficiency. Substrates with electronic wastes and crumb rubber had a higher efficiency in removing BOD 5 , TSS, and COD, which shows the superior characteristics of wastewater treatment by these wastes. Key words: Municipal Wastewater Treatment; Chemical Electro Microbial Process; Electrobacter; Waste

• Cathodic dynamic membrane (CDM) was developed to treat wastewater in AnMBR (AnCDMBR). • Well-controlled fouling and efficient separation were observed in CDM with low cost. • AnCDMBR achieved superior CH 4 yield rate of 0.26 L-CH 4 /g-COD with high purity (>95 %). • Enhanced metabolism and spatially heterogeneous microbiota promote bioenergy recovery. • It shows significant potential for AnCDMBR in municipal wastewater treatment. Concerns regarding membrane fouling and suboptimal bioenergy recovery have constrained the implementation of anaerobic membrane bioreactor (AnMBR) for treating low-strength municipal wastewater. This study presents a novel anaerobic cathodic dynamic membrane bioreactor (AnCDMBR) designed to address these challenges. A self-formed cathodic dynamic membrane (CDM) on inexpensive carbon cloth was developed to function as both a membrane and biocathode to achieve dual-function effects of mitigating membrane fouling and accelerating organics conversion. Compared with common dynamic membrane (1.52 kPa/d) and commercial membranes (7.52 kPa/d), the developed CDM presented a significantly reduced fouling rate (1.02 kPa/d), exhibiting the potential as a substitute for high-cost conductive membranes. Furthermore, efficient and stable biomethanation occurred in AnCDMBR with a superior methane yield rate of 0.26 L-CH 4 /g-COD (CH 4 content > 95 %), which was 1.42 times higher than the control, linked to the higher activities of microbial metabolism and methanogenic-related key enzymes. Further analysis revealed that electrostimulation-induced niche differentiation of microbiota regulated interspecies interactions between electroactive microorganisms and complex anaerobic digestion microbiomes, facilitating organic matter conversion to methane and leading to superior bioenergy recovery. This study offered a new strategy for effectively mitigating fouling and recovering bioenergy from low-strength wastewater, potentially expanding the application of AnMBRs. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, the performance of the membrane bioreactor (MBR) and anoxic–aerobic sequencing batch reactor (SBR) are compared in treating municipal wastewater. The aim of the work was to determine the feasibility of these systems for the removal of organics matter and nutriments from the municipal wastewater. The MBR displayed a superior performance with removal efficiencies exceeding 99% for TSS, 94% for chemical oxygen demand (COD) and an improvement on SBR efficiencies was found. In the same way, the MBR produced an effluent with much better quality than SBR in terms of total nitrogen (TN) and total phosphorus (TP) removal efficiencies. Combining membrane separation and biodegradation processes or the membrane bioreactor (MBR) technology improved pollution removal efficiencies significantly. Highlights Municipal wastewater treatment.; Membrane bioreactor process.; SBR process evaluation.; Organic pollution removal.; Reuse in irrigation.;

Efficient disinfection is of prime importance for safe drinking. Despite Kolkata’s significant progress in the socio-economic fronts, the conservative and disjointed approaches used in dealing with the city’s sanitation and wastewater treatment problems have collectively made it one of the hotspots of water-borne diseases, resulting in thousands of deaths per year. Additionally, the high operating cost of the conventional wastewater treatment plants based in Kolkata poses a major concern. This study has therefore, for the very first time integrated geothermal heat sinks with concentrated solar power for wastewater treatment, replacing the need for mechanical heat exchangers and excess cooling water requirement. It is estimated that nearly 67% of the total operating cost of the treatment process associated with disinfection would be reduced, along with zero electricity consumption for cooling the high temperature treated effluent. The study reports that with addition of catalyst, namely TiO2, the disinfection could be further enhanced by removing almost 99.999% of the microbial population. Applications of geothermal heat sinks are available in other domains such as building heating or cooling, refrigerated storages and many others, but, literature specific to its use in wastewater treatment is missing till date.

Sewage sludge management at wastewater treatment plants is becoming a more and more challenging task. Here, an innovative integrated modeling approach is developed to investigate the optimization of a municipal wastewater treatment plant (MWWTP) by the inclusion of hydrothermal carbonization (HTC). To this aim, two alternative plant layouts have been considered: (i) a conventional activated sludge-based treatment plant, i.e., based on thickening, stabilization, conditioning, and dewatering; (ii) additional hydrothermal carbonization and integrated treatment of the spent liquor in the sludge line. An Italian MWWTP has been selected as a case study, and three different scenarios have been implemented in the process simulation software World Wide Engine for Simulation Training and Automation (WEST) by considering the effect of the different digestion times in the aerobic reactor. Then, according to the Design of Experiment (DoE) methodology applied both on simulated and experimental data, and by the use of a Python code, the desired models have been developed and compared. Finally, a Life Cycle Assessment (LCA) study has been carried out to estimate the impacts on human health, ecosystems, and resources. The integration of HTC corresponds to the generation of a valuable product (the hydrochar), whereas the conventional layout is associated with high disposal costs of the sewage sludge. According to LCA results, a sludge age of 40 days is recommended due to the lowest impacts estimated, both with and without a HTC section. This has been ascribed mainly to the electricity demand of the sludge line, which increases with the excess sludge flow rate, i.e., as the sludge age decreases.

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In this study, we investigated whether bacterial community composition in full-scale wastewater treatment bioreactors can be better explained by niche- or neutral-based theory (deterministic or stochastic) and whether bioreactor design (continuous flow versus fill and draw) affected community assembly. Four wastewater treatment facilities (one with quadruplicated continuous-flow bioreactors, two with one continuous-flow bioreactor each, and one with triplicate fill-and-draw bioreactors) were investigated. Bioreactor community composition was characterized by sequencing of PCR-amplified 16S rRNA gene fragments. Replicate bioreactors at the same wastewater treatment facility had largely reproducible (i.e., deterministic) bacterial community composition, although bacterial community composition in continuous-flow bioreactors was significantly more reproducible (P< 0.001) than in fill-and-draw bioreactors (Bray-Curtis dissimilarity, m = 0.4860.06 versus 0.5860.08). Next, we compared our results to previously used indirect methods for distinguishing between deterministic and stochastic community assembly mechanisms. Synchronicity was observed in the bacterial community composition among bioreactors within the same metropolitan region, consistent with deterministic community assembly. Similarly, a null model-based analysis also indicated that all wastewater bioreactor communities were controlled by deterministic factors and that continuous-flow bioreactors were significantly more deterministic (P < 0.001) than fill-and-draw bioreactors (nearest-taxon index, μ = 3.8 ± 0.6 versus 2.7 ± 0.8). Our results indicate that bacterial community composition in wastewater treatment bioreactors is better explained by deterministic community assembly theory; simultaneously, our results validate previously used but indirect methods to quantify whether microbial communities were assembled via deterministic or stochastic mechanisms. [ABSTRACT FROM AUTHOR]

Anaerobic membrane bioreactor (AnMBR) offer promise in municipal wastewater treatment, with potential benefits including high-quality effluent, energy recovery, sludge reduction, and mitigating greenhouse gas emissions. However, AnMBR face hurdles like membrane fouling, low energy recovery, etc. In light of net-zero carbon target and circular economy strategy, this work sought to evaluate novel AnMBR configurations, focusing on performance, fouling mitigation, net-energy generation, and nutrients-enhancing integrated configurations, such as forward osmosis (FO), membrane distillation (MD), bioelectrochemical systems (BES), membrane photobioreactor (MPBR), and partial nitrification-anammox (PN/A). In addition, we highlight the essential role of AnMBR in advancing the circular economy and propose ideas for the water-energy-climate nexus. While AnMBR has made significant progress, challenges, such as fouling and cost-effectiveness persist. Overall, the use of novel configurations and energy recovery strategies can further improve the sustainability and efficiency of AnMBR systems, making them a promising technology for future sustainable municipal wastewater treatment. [Display omitted] • AnMBR offers a sustainable approach for municipal wastewater treatment. • Novel configurations in membrane fouling and energy recovery are introduced. • AnMBR hybrid processes in improving nutrient recovery efficiency are discussed. • The role of AnMBR in advancing the circular economy are proposed. [ABSTRACT FROM AUTHOR]