We first examine the financial viability of investments for wastewater treatment systems by looking at the potential sources of revenue. Then, we go on to argue why we need to look at the economic viability of the investments under reuse and recycling. The article describes four distinct scenarios of reuse of wastewater that exist in India, which influence the number and types of economic benefits that can be derived from wastewater treatment, and discusses how the three benefit streams vary according to the physical and socio-economic conditions, to conclude where the systems would be economically viable. In the same way, it also discusses the conditions ideal for improving the viability of wastewater recycling. A key message is that while the cost of production and supply of water for various uses will be high in regions facing acute water shortages, the benefits from wastewater treatment will also be quite high in such regions.HIGHLIGHTSThe financial viability of investments for wastewater treatment systems is India is examined. There are four distinct scenarios that exist in India, which influence the number and types of economic benefits that can be derived from reuse of treated wastewater. The three types of benefits from wastewater treatment, viz., direct economic, indirect economic and ecological vary according to the physical and socio-economic conditions. The conditions ideal for improving the viability of wastewater recycling are discussed. While the cost of production and supply of water for various uses will be high in regions facing acute water shortages, the benefits will also be quite high in such regions.

Resource recovery from wastewater treatment plants is crucial for India's circular economy, as emphasized by the National Draft Water Reuse Norms 2024. This study assessed resource recovery technologies using circularity and sustainability frameworks to inform technology selection. A multiple-criteria decision analysis compared three innovative and two reference treatment trains in Kanpur, India, based on treatment performance, costs, and resource recovery potential. Quantitative microbial risk and life cycle assessments further evaluated health and environmental impacts. Innovative systems, such as Andicos (ultrafiltration + co-digestion) and SFD-MBR (slow-forming dynamic membrane bioreactor) had slightly lower performance indices (Delta PI: 0.13-0.14) than the reference system MBR due to lower nutrient removal. The innovative systems generated 1.2 to 2 times more revenue from selling water, nutrients, and energy. Further, reusing nutrient-rich treated effluents for irrigation reduced eutrophication potential by 94%. Treatment trains with constructed wetland plus (CW+) achieved the highest faecal coliform (FC) removal, meeting reuse norms of <5 CFU/100 mL, potentially preventing up to 2,600 gastrointestinal infections annually among 4,000 farmers using the water for irrigation. This study highlights the environmental, health, and economic benefits of innovative wastewater treatment technologies for advancing resource recovery in India.

This chapter summarises the key findings from the previous chapters. It unveils that the solutions prescribed for tackling the un-surmountable water challenges of urban areas of India are often too simplistic. There are no “straight jacket” solutions for addressing urban water challenges. The opportunities and constraints for implementing sustainable solutions need to be identified through a thorough analysis of the characteristics of the water supply systems comprising the urban water cycle and the physical infrastructure, and the water use system comprising the various sectors of water use and the factors influencing the demand for water. In order to affect changes in the management systems for enhanced performance of urban water utilities, the line agencies dealing with different aspects of urban water management might require reorientation or restructuring, and new institutions may need to be created for the purpose of infusing incentives, accountability and transparency.

The study investigates into the factors responsible for the variation in COVID-19 infections and death rates reported across Indian states. The analysis considered the following state-wise data: proportion of people living in cities with population density higher than 5,000 persons per sq. km, average climatic conditions, health infrastructure per thousand population, per capita Net State Domestic Product, and proportion of aged (above 60) people identified on the basis of an extensive review of the international scientific literature published on the pandemic, covering both COVID-19 infections and mortality. As regards COVID-19 infections, the proportion of people living in densely populated areas (above 5,000 persons per sq. km), per capita Net State Domestic Product (NSDP), proportion of aged people and climate explained the variation across states. While the first three variables had a positive influence on the infection rates, incidence of infections increased from hot & arid climate to cold & humid climate. As regards the deaths due to COVID-19, in addition to these three factors, health infrastructure per unit population was found to affect, with its impact on COVID-19 related mortality being negative. But the effect of the factors such as the proportion of aged people (above 60 years), the per capita Net State Domestic Product and the proportion of population living in densely populated areas on COVID-19 induced mortality was positive. Like in the case of COVID-19 infections, the chances of mortality increased from hot & arid regions to cold & humid regions.

This study investigates the factors influencing groundwater behaviour during the monsoon using data on rainfall, pre-monsoon depth of the water levels, groundwater level fluctuations, aquifer specific yield, and soil infiltration characteristics. It shows the effect of pre-monsoon depth of the water levels along with rainfall, soil infiltration and specific yield in controlling recharge during the monsoon. It also explores the factors influencing the performance of drinking water schemes. It shows that the intensity of irrigation demand, extent of gravity-based surface irrigation, aquifer storage space, and the aquifer recharge potential are important determinants for the sustainability of the groundwater-based drinking water schemes.

The article critically reviews the methodology adopted by the Central Ground Water Board (CGWB) for the assessment of groundwater resources in India. The authors developed a water balance equation that simulates the changes in annual and seasonal groundwater storages of an agricultural region, using a water accounting framework; they solved the developed equation using the data of annual and seasonal water level fluctuations for a wet year for Ludhiana district of Punjab to estimate different components of the water balance. The estimated values are used to test the robustness of the CGWB methodology for monsoon recharge. The annual groundwater storage change obtained from solving the water balance equation was compared with the observed change in annual groundwater storage and was found to closely tally. As per the water balance equation, the CGWB estimates of rainfall recharge conform to the annual water level fluctuations recorded by the agency and therefore are not reliable. Hence, we could infer that our methodology is superior to that of CGWB for estimating monsoon recharge. The validated equation was also used to estimate the recharge from rainfall during a dry year. Using these outputs in a simple groundwater balance equation, irrigation return flows were estimated for the wet and dry years. The equation was then extended to the Ahmednagar district of Maharashtra, a hard rock area, for estimating the surface water import during a wet year, the key unknown in the region's water balance. Hence, our methodology can be employed to estimate rainfall recharge for dry years using annual changes in groundwater storage and estimated consumptive uses of water, when the "WLF approach," used by CGWB, fails, owing to the presence of an additional variable, that is, monsoon draft. For wet years, it can be used to arrive at the consumptive use of water for various purposes.