Technology choices in scaling up sanitation can significantly affect greenhouse gas emissions and the fertiliser gap in India

Abstract

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.

Life cycle assessment of wastewater treatment in developing countries: A review

“…Only 23% of the studies include any kind of uncertainty analysis ( Figure 3) compared with 40% in developed countries (Corominas et al, 2013).The pedigree matrix (Weidema and Wesnaes, 1996) or Monte Carlo analysis (Heijungs and Huijbregts, 2004) are common tools in LCA and their use should be general and not exceptional (e.g. Hernández-Padilla et al, 2017;Kulak et al, 2017) in WWT-related LCAs in developing countries.…”

“…Other studies consider p.e. as FU from different approaches like p.e./household (Kulak et al, 2017), the urine, faeces and grey water discharged annually by p.e. (Lam et al (2015) (Pan et al, 2011;Casas Ledón et al, 2017)).…”

Conceptual environmental impact assessment of a novel self-sustained sanitation system incorporating a quantitative microbial risk assessment approach

“…Based on the scientific literature, after the treatment period both products can be used as organic fertilizers in local fields, provided that proper sanitization is attained ( Andersson, 2015 ; Karak and Bhattacharyya, 2011 ; Kirchmann and Pettersson, 1995 ; Petersens and Beck-friis, 2012 ). However, although the social acceptability of their use in agriculture varies considerably among the developing countries ( Moilwa, 2007 ; Mugivhisa, 2015 ), in this environmental study the given products have been considered scientifically acceptable, similarly to other relevant LCA studies ( Kulak et al, 2017 ; Remy and Jekel, 2008 ; Flores et al, 2009 ).…”

“…Based on their research findings, certain source separation methods manifest a better profile over the conventional wastewater treatment for selected impact categories. Only a few studies have assessed the environmental impact of different toilet systems -flush, composting, pit latrine and source-separating toilets-, either on a standalone basis ( Kohler Co, 2014 ) or along with the involved waste and/or wastewater activities ( Anand and Apul, 2011 ; Devkota et al, 2013 ; Gao et al, 2015 ; Kulak et al, 2017 ). Although the aforementioned studies provide important views on the environmental performance and relative competitiveness of existing sanitation alternatives, a new approach to the life cycle assessment of such systems is proposed by incorporating the health risks linked to pathogen exposure.…”

Sustainable sanitation and gaps in global climate policy and financing

“…Although relatively small compared with other GHG sources, these emissions require consideration in planning of sanitation and wastewater systems. Providing sanitation access to 800 million people in India through pit latrines would cause increases in India's annual GHG emissions, equivalent to 7% of current levels 21 . The climate impact of providing 2.3 billion people who still lack access to basic sanitation with services such as pit latrines could more than double the GHG emissions from this source 22 .…”