Nearly 800 million people in India lack access to adequate sanitation. The choice of technology for addressing this need may have important sustainability implications. In this study, we used life cycle assessment to compare environmental impacts and nutrient recovery potentials of four different options for providing everyone in India with access to improved sanitation: (i) centralised wastewater treatment with sequential batch reactors (SBR), (ii) twin-pit latrines, (iii) latrines with source separation only and (iv) latrines with source-separation of urine and faeces connected to biogas plants. Results revealed large variability. Closing the sanitation gap through pit latrines would be expected to cause large increases of India's annual greenhouse gas (GHG) emissions, equivalent to 7% of current levels. Source separation only and centralised plants with SBR will be associated with lower GHG emissions, while the biogas scenario shows a potential to provide net emission reduction. The study revealed that source separating systems can provide significant quantities of plant available nitrogen and phosphorus at the country level. Future research should include more technological options and regions. Methodology piloted in this study can be integrated into the planning and design processes for scaling up sanitation in India and other countries.

Little has been studied about the potential risks and hazards arising from the use and operation of container-based sanitation (CBS) systems. Building on existing risk assessment frameworks, this case study aimed to identify exposure risks from faecal pathogens and relevant control measures in a CBS service chain. The case study employed a mixed-methods approach that included environmental sampling, key informant interviews, and direct observation. This inclusion of a behavioural dimension reflects a socio-cultural approach to risk analysis that is less evident in overtly quantitative approaches to risk assessment that are typical of the health risk field. Data from this case study was collected in Naivasha, Kenya in July 2016. The hazard intensity and role of specific transmission routes was validated by environmental sampling, which found a high level of faecal contamination on toilet surfaces and a consequent high risk of hand-to-mouth infection for users and operators. The hazard analysis identified nine critical control points where exposure risks may be either prevented or reduced via the implementation of relevant control measures. We discovered that the production of exposure risks was related to multiple, interrelated causal mechanisms and risk factors, findings we expect will guide approaches to exposure risk management in the future.

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