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India, being a developing country, faces big challenges in ensuring water, sanitation, and hygiene (WASH) for all. This case study presents the performance evaluation of a large wastewater management and sanitation-related infrastructure in a metropolitan city in North India. "Dravyavati River Project" is the major sanitation program of the water-stressed Jaipur city based on the concept of river rejuvenation of the long-lost Dravyavati River which flows across the city. The project envisages integrated urban water management such that it aims at the collection and treatment of wastewater (sewage network and treatment plants), safe disposal, ensuring continuous unpolluted flow, geological and ecological integrity to strengthen public health, to reduce the impact of water stress on the total water cycle by promoting groundwater recharge, and improvement in biodiversity. The technical assessment is based on the primary and secondary data collection of field samples and laboratory analysis of influent and effluent samples collected from the five sewage treatment plants (STPs). The results suggest that the project has largely delivered the envisaged environment, public well-being, and ecological and socioeconomic benefits, but there are substantial gaps in the conceived outputs and actual performance. The challenge lies in bridging these gaps and overcoming operational inefficiencies to ensure the sustainability of the Dravyavati River rejuvenation. [ABSTRACT FROM AUTHOR]

Several Sewage Treatment Plants (STPs) have been set up in India to tackle sewage. With the growing awareness that gas produced while treatment is a rich source of methane and can be used for heating purposes, these STPs are upgraded with bio-methane technology wherein methane is transformed into electricity to run the plant itself. However, most of these plants are running under-capacity due to a shortage of funds for operation and maintenance. This study aims to determine whether biofuel produced within STPs can be marketed as a cooking fuel (compressed bio-methane (CBM) gas) to fund these plants' revenue-generated operation to promote clean technology and circular economy. A SWOT analysis has been conducted, and the average willingness to pay for CBM equivalent to14.2 kg LPG in calorific value is INR 340 (USD 4.55), whereas its average variable cost is approximately INR 240 (USD 3.21). Moreover, since the net present value of marketing CBM is positive (INR 219 million/USD 2.93 million), and the internal rate of return is 33%, the study concludes that marketing CBM for cooking is economically viable. Through its findings, this study instigates further research to check the marketability of this biofuel as a cooking fuel in the case of other existing STPs with lesser treatment capacity. [ABSTRACT FROM AUTHOR]

Sewage treatment plants (STPs) are considered as a prominent source for releasing microplastics (MPs) into the riverine systems. Though MPs abundance and removal efficacy in different secondary treatment technique-based STPs have been extensively studied worldwide, such studies are scarce in Indian conditions. Herein, this study comprehensively assesses MPs abundance, characterization, and their removal in the selected secondary treatment technique-based STPs discharging into the middle stretch of the Ganga River in India. MPs concentration (n/L) in influent and effluent of the STPs varied between 42 ± 10 to 150 ± 19 and 3 ± 1 to 22 ± 5, respectively. Overall, the primary treatment stage was observed to remove MPs by 23-42 %, while the secondary treatment stage removed MPs by 67-90 %. Selected technique-based STPs exhibited varying MPs removal efficacies as follows: SBR (94 %), TF (90 %), AL (88 %), UASB (87 %), ASP (85 %), FAB (84 %), and Bio-tower (77 %). MPs ranging from 50 to 250 μm were the dominant sizes, with PP, PE, and PS being the prevalent polymers. The Ganga River receives about 3 × 10 8 MPs/day from STP effluents, and an estimated 4.5 × 10 7 MPs/day are released via the sludge. This comprehensive assessment of MPs abundance and removal from different technology-based Indian STPs will allow the comparison of the generated dataset with similar studies worldwide., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this manuscript., (Copyright © 2023 Elsevier B.V. All rights reserved.)

This paper assesses the technical and economic sustainability of a combined system of an up-flow anaerobic sludge blanket (UASB)–down-flow hanging sponge (DHS) for sewage treatment. Additionally, this study compares UASB–DHS with current technologies in India like trickling filters (TF), sequencing batch reactor (SBR), moving bed biofilm reactor (MBBR), and other combinations of UASB with post-treatment systems such as final polishing ponds (FPU) and extended aeration sludge process (EASP). The sustainability of the sewage treatment plants (STPs) was evaluated using a composite indicator, which incorporated environmental, societal, and economic dimensions. In case of the individual sustainability indicator study, the results showed that UASB-FPU was the most economically sustainable system with a score of 0.512 and aeration systems such as MBBR, EASP, and SBR were environmentally sustainable, whereas UASB–DHS system was socially sustainable. However, the overall comparative analysis indicated that the UASB–DHS system scored the highest value of 2.619 on the global sustainability indicator followed by EASP and MBBR with scores of 2.322 and 2.279, respectively. The highlight of this study was that the most environmentally sustainable treatment plants were not economically and socially sustainable. Moreover, sensitivity analysis showed that five out of the seven scenarios tested, the UASB–DHS system showed good results amongst the treatment system. [ABSTRACT FROM AUTHOR]

Little is known about the occurrence of emerging environmental contaminants, such as benzotriazoles (BTRs), benzothiazoles (BTHs), benzophenones (BzPs), and bisphenol analogues (BPs) in India. In this study, we determined the occurrence and removal of BTRs, BTHs, BzPs, and BPs in five Indian sewage treatment plants (STPs). The respective measured mean concentrations ( N = 5) in influents and effluents were 370 and 57.4 ng L −1 for BTRs, 50800 and 20200 ng L −1 for BTHs, 351 and 163 ng L −1 for BzPs, and 98.0 and 9.6 ng L −1 for BPs. Among the target chemicals analyzed, BTHs were found at elevated levels, and the measured levels were some of the highest ever reported in the literature. The mean concentrations ( N = 5) of BTRs, BTHs, BzPs, and BPs in sludge were 44.2, 51200, 124, and 200 ng g −1 dry wt, respectively. The removal efficiencies for BTRs, BTHs, BzPs, and BPs ranged as follows: 54.2–85.6%, 23.4–85.0%, 51.8–71%, and 76.0–97.0%, respectively, and were comparable to those reported for other countries. Elevated concentrations of BTHs in Indian STPs can be related to consumption of these chemicals in a wide range of products including paper, textile and rubber materials. [ABSTRACT FROM AUTHOR]

Carbon sequestration is a new technology that is gaining importance in combating the harmful effects of global warming. The potential for carbon sequestration from domestic sewage treatment plants operating in India was studied. Based on the data provided by the Government of India on the generation of domestic sewage by State, the organic load generation, sequestration potential and net release of CO2 were calculated. By going in for carbon sequestration, domestic sewage treatment in India has a potential to be a carbon neutral sector with a capacity to store 22 thousand tonnes of CO2 every day at current levels. The Government of India's focus is on increasing the share of renewable energy sources to combat emissions; however, carbon sequestration technology would be an ideal solution for deployment over the time period required for renewable energy' share to become significant. Three metro cities, viz., Delhi, Mumbai, and Chennai are immediate prospects that could adopt this technology, followed by other cities. The prevalent Renewable Energy Credit Trading Scheme in India can support carbon sequestration technology infusion. © 2016 American Institute of Chemical Engineers Environ Prog, 36: 162-170, 2017 [ABSTRACT FROM AUTHOR]

Sewage treatment plants (STPs) as a carrier of microplastics (MPs) have received considerable attention worldwide recently. In India, the majority of studies on MPs have been conducted in sediments, riverine, and marine systems, while knowledge on MPs occurrence in STPs is scarce. Henceforth, this work evaluated the presence of MPs in sewage and sludge in a hybrid growth, secondary treatment-based STP system. Optical microscopy, scanning electron microscopy (SEM), and Fourier-transform infrared (FTIR) spectroscopy methods were used to examine the abundance of MPs in raw sewage, effluent from different treatment units of the STP, and sludge samples. A total number of MPs of 201 ± 19 (2021) and 197 ± 22 (2022) were detected in the studied STP system. Results showed that MPs ranged between 64.3 ± 4.89–47.66 ± 4.71 n/L (sewage) and 1.14 ± 0.30–1.38 ± 0.65 n/g (sludge) with the overall removal efficacy of the studied STP estimated to be around 80%. Fragments and fibers were predominant among all shapes and particles mostly belonged to sizes <50 μm and <50 μm–250 μm in sewage and sludge, respectively. In total, seven polymers were identified of which low-density polyethylene (LDPE) constituted the highest proportion in sewage (26%–31%) and polyvinyl chloride (PVC) contributed the highest in the sludge (22%–27%). Moreover, MPs control measures have been discussed based on the findings of this study to restrict MPs re-entry into the environment via treated effluent and sludge. [Display omitted] • First study on MPs occurrence and removal in a hybrid growth MBBR-based STP. • Around 80% MPs were removed via the primary and secondary treatment stages in the STP. • LDPE (in sewage) and PVC (in sludge) were the most prevalent polymers. • Small-sized MPs (<250 μm) like fragments and fibers were predominant shapes. • Advanced treatment options for MPs removal from secondary-treated effluent discussed. [ABSTRACT FROM AUTHOR]

The presence of antibiotics in the aqueous environment can alter the water microbiome, inducing antimicrobial resistance genes. Hence, the occurrence of 18 antibiotics belonging to sulfonamides, fluoroquinolones, tetracyclines, phenicols, and macrolides classes were investigated in surface water, groundwater, and sewage treatment plants in Chennai city and the suburbs. Fluoroquinolones had the maximum detection frequency in both influent and effluent samples of urban and suburban STPs, with ofloxacin and ciprofloxacin showing the highest influent concentrations. Erythromycin was the predominant antibiotic in surface water samples with an average concentration of 194.4 ng/L. All the detected antibiotic concentrations were higher in the Buckingham Canal compared to those in Adyar and Cooum rivers, possibly due to direct sewer outfalls in the canal. In groundwater samples, ciprofloxacin showed the highest levels with an average of 20.48 ng/L and the concentrations were comparable to those of surface water. The average sulfamethazine concentration in groundwater (5.2 ng/L) was found to be slightly higher than that of the surface water and much higher than the STP influent concentrations. High levels of ciprofloxacin and sulfamethazine in groundwater may be because of their high solubility and wide use. Moreover, erythromycin was completely removed after treatment in urban STPs; FQs showed relatively lesser removal efficiency (2.4-54%) in urban STPs and (8-44%) in suburban STP. Tetracyclines and phenicols were not detected in any of the samples. Ciprofloxacin and azithromycin in surface water pose a high risk in terms of estimated antibiotic resistance. This study revealed that the measured surface water concentration of antibiotics were 500 times higher for some compounds than the predicted calculated concentrations from STP effluents. Therefore, we suspect the direct sewage outlets or open drains might play an important role in contaminating surface water bodies in Chennai city., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Unfortunately, there are globally various examples of poor wastewater planning and management of poorly targeted government investments that targeted low priority problems ineffectively. Integrated wastewater management is essential for responsible use of the environment and affordable provision of services within an overall water resources management system. About 7.5 % of all deaths in India are due to deficiencies in safety of water sanitation or hygiene. The effective use of treated effluent for gardening, industries can save the potable water which can be sufficiently utilised in draughts in States like Rajasthan where underground water is the main source of water supply. During present work, a study has been undertaken for integrated wastewater management system for Jaipur city. The city has sufficient sewage treatment plants (STPs) to meet the wastewater generated. An attempt has been made through this article to understand the present available system to handle the water scarcity issues effectively and to suggest that no sustainable solution is likely to come up until an integrated approach including socio-political reasons behind wastewater pollution is achieved. [ABSTRACT FROM AUTHOR]