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Efficient domestic wastewater management is essential for mitigating the impact of wastewater on human health and the environment. Wastewater management with conventional technologies generates sewage sludge. The present study considered a modelling approach to evaluate various processing pathways to produce energy from the sewage sludge. Anaerobic digestion, gasification, pyrolysis, and hydrothermal liquefaction are analysed in terms of their energy generation potentials with the Aspen Plus software. A techno-economic assessment is performed to assess the economic viability of each pathway. It reveals that gasification appears as the most promising method to produce electricity, with 0.76 kWh/kg drysludge , followed by anaerobic digestion (0.53 kWh/kg drysludge), pyrolysis (0.34 kWh/kg drysludge), and hydrothermal liquefaction (0.13 kWh/kg drysludge). In contrast, the techno-economic analysis underscores the viability of anaerobic digestion with levelized cost of electricity as 0.02 $/kWh followed by gasification (0.11 $/kWh), pyrolysis (0.14 $/kWh), and hydrothermal liquefaction (2.21 $/kWh). At the same time, if the products or electricity from the processing unit is sold, equivalent results prevail. The present study is a comprehensive assessment of sludge management for researchers and policymakers. The result of the study can also assist policymakers and industry stakeholders in deciding on alternative options for energy recovery and revenue generation from sewage sludge. [Display omitted] • Comparative analysis of four sewage sludge processing units. • Gasification produces 41% more electricity than anaerobic digestion. • Anaerobic digestion has 81% lower LCOE than gasification. • Pyrolysis has the highest energy content per kg. • Anaerobic digestion has the highest NPV through electricity or other products. [ABSTRACT FROM AUTHOR]

Transport sector electrification will play a critical role in achieving India's net zero emission target by 2070; however, the adoption of EVs is hindered by challenges such as long charging times, high ownership costs, and limited range. Battery swapping (BS) offers quick recharging, unlike point charging (PC). This study examines BS subscription fees in India's passenger sector (buses, four-wheelers, three-wheelers, and two-wheelers). Furthermore, the assessment of its effects on EV adoption, the energy mix, and CO 2 emissions in India's passenger sector is analysed using the global change analysis model (GCAM). The results show that BS is cost-effective for four-wheelers and two-wheelers without subsidies. Providing similar subsidies to BS as to PC achieves cost parity or lower costs for three-wheelers and buses compared to PC. BS could reduce CO 2 emissions by 9 % by 2070, with a 6 % increase in EV adoption and an 8 % rise in electricity demand. With BS subsidies, EV penetration may increase by 10 %, resulting in a 14 % reduction in CO 2 emissions compared to PC. The study suggests BS is a viable option but may not entirely replace PC. [Display omitted] • Battery swapping (BS) and point charging (PC) for EV charging were compared. • BS business models to compute subscription fees were developed. • BS is feasible for 4W and 2W without subsidy, and with subsidy for 3W and buses. • Compared to PC, EV adoption is projected to increase by 6 % with BS in 2070. • With subsidy, CO 2 emissions will be reduced by 14 % compared to PC in 2070. [ABSTRACT FROM AUTHOR]