Improving Rural Wastewater Management

Improved sanitation and hygiene through proper wastewater management is critical !'or sustainable growth of rural oommunltles. Traditional wastewater treatment technologies experience low penetration in the resourcepoor semi-arid troplcal villages with limited or no access to good quality electricity and skilled supervision. Th.e substandard wastewater treatment effictencies of traditional effiueni treatment plants. even in the urban centres, are testimony of their unviabHity In rural India, Constructed wetland (CW) Is an age-old.low-cost. decentral~ed wastewater treatment technology; The absence of heavy metal and other xenooiotics in rural grey water highlights their reuse potential for growing jute, flower. teak plantation. etc. Lack or field-scale study with real wastewater thus far has made policy makers and professionals working in the sanitation sector sceptic about the long-tenn reliability of CWs with respect to wasteWllter treatment efficiencies. This chapter is an attempt to present the potential and real-life challenges of CW implementation. 12.1 Significance of Decentralized Wastewater Treatment Water, food and energy securities are emerging as increasingly important and vital issues for India and the world. Most of the river basins in India and elsewhere are experiencing moderate to severe water shortages due to the simultaneous elTects of agricultural growth. industrialization and urbanization. One in every n ine persons in the world today does not have access to safe and clean drinking water. There is a need to enhance the water use efficiency in the agricultural sector which consumes about 70% of the total anthropogenic withdrawal of 3928 kmJ/year (WWAP, 2017). Research and resources are thus necessary to find a more efficient, productive, • Corresponding authof: a.datta@cgiar.CKg equitable and environmentally friendly way of using wastewater in agriculture. so that quality of crop, soil and human health is not compromised. There needs to be focused effort to maximize the potential of wastewater as a valuable and sustainable resource. 12.1.1 Rural wastewater as a sustainable resource About 80% water supplied to a household comes out as waste water; thus as long as households and human habitats exist. wastewater generation will take place. It is worth mentioning. as often the obsession with groundwater and rainwater statistics prompts us to declare cluster of CCAB lntomatiooal 2018. Corporate Social ResponsibHity: Win-win Propositions for Communities, Corporates 8fld Agriculture (ads S.P. Wani and K.V. Raju) 213 214 ©CAB International 2018 for Girish Chander A. Dalta et al. villages as 'dry' and hence no wastewater management activity is viable. Unfortunately the sheer number of such villages in the semi-arid tropics is large and the marginalized population living there is in need of waste water management, at least for better health and hygiene. Often the wastewater generated from these resourcepoor households is easily biodegradable and sImple low-cost technology like constructed wetland (CW) can abate the environmental degradation. On a macro-scale, the effect of such small-scale scientific interventions cumulatively has the potential to influence major environmental degradation. Here it has to be mentioned that often local contractual engineers. and sanitation and rural health professionals do not prefer small-scale interventions for reasons pertaining to financial profit rather than environmental concern. Postindependence the focus of rural development in India has been on establishing schools, health care facilities. housing and drainage network. In the absence of a proper wastewater management scheme. however the health and hygiene of rural India has suffered. Pestand vector-borne diseases such as malaria. chikungunya. etc. are impossible to eradicate in the absence of a proper wastewater treatment scheme. In recent years sanitation and cleanliness has received unprecedented attention of the Government of India through the Swachh Bharat mission. Good drainage network is the prerequisite of any rural wastewater management scheme. Moreover. maintaining proper slope of the drains and proper village-level maintenance of the drains are important and should be the starting point for any rural wastewater management scheme. 12.1.2 Impact of Improper rural wastewater management on health and hygiene The link between wastewater management and health is well documented. In developing countries as much as 80% of illness is linked to inaccessibility of good quality potable water. In 2012. an estimated 842.000 deaths in middleand low-income countries were caused by contaminated drinking water. inadequate hand washing facilities and sanitation services (WHO. 2014). Additionally, 361.000 deaths among children aged below 5 years could have been prevented through reduction of risks related to inadequate hand hygiene. sanitation and water during the same year (Pruss-Ostun et al., 2014). Raw wastewater discharge contributes towards water pollution and critically affects the actual availability of potable water and thus adversely impacts the ecosystem services (Corcoran et al .. 2010) through eutrophication. groundwater pollution. etc. Annual health cost per child in an untreated wastewater irrigated environment is estimated to be about NOOO/annum (-US$60), which is 73% higher than for freshwater irrigated areas (Grangier et al., 2012). Srikanth and Naik (2004) reported that the prevalence of giardiasis among farmers irrigating with wastewater in a suburb of Asmara. Rritrea was 45%. Based on hospital data they found that giardiasis prevalence was 7% among residents of the community who consumed only vegetables grown with untreated waste water compared with 1% for residents in similar towns in Eritrea without wastewater irrigated crops. Melloul and Hassani (1999) found higher rates of salmonella infection in children living in wastewater-irrigated areas near Marrakesh. Morocco compared with those living in areas without wastewater irrigation (Chary et al .. 2008). Organic pollution which affects around one-seventh of a ll river stretches in Africa. Asia and Latin America (UNEP. 2016) can have severe impacts on the livelihoods of poor rural communities depending on fisheries or natural resources. For every US$ 1 invested in water and sanitation. there is an economic return of US$3 to US$4 (WHO, 2015). Planned and safe irrigation practices with waste water will significantly help in nutrient recycling. For example. the phosphorus load of the waste water when discharged in surface water bodies triggers eutrophication. Remarkably, the sources of extractable phosphorus are dWindling and is estimated to become scarce or exhausted in the next 50-100 years (Van Vuuren et al .. 2010). This makes phosphorus recovery from wastewater financially viable. Recycling human urine and faeces can provide steady supply chain for phosphorus for about 22% of the present anthropogenic demand (Mihelcicet al., 2011). Phosphorus recycling to agriculture through decentralized wastewater treatment (DWAT) schemes is fairly straightforward. Moreover. such initiatives will reduce the input cost and chemical dependency of agriculture increasing the net income of farmers (Winblad and Simpson-Hebert. 2004). Treated grey water can be sUitably utilized. to ©CAB International 2018 for Girish Chander Improving Rural Wastewaler Management 215 produce bio-ethanol (both first and second generation) through sweet sorghum cultivation. 12.1.3 Wastewater irrigation: prevailing practice, potential and risks Use of wastewater in agriculture is not new as its ferti lizer value is well recognized: however. re liable estimates of projected waste water use in agriculture are scarce in literature (Qadir et al., 2007). Moreover. these farming activities often remain informal and are not indicated in official statistics (Drechsel et al .. 2006). Globally about 800 million farmers are engaged in urban agriculture. of whom about 200 million practise market-oriented farming on small peri-urban plots using wastewater. Sometimes farmers use raw wastewater. as it provides nutrients or is more reliable or cheaper than other water sources (Keraita and Drechsel, 2(04). For example. in rural Sri Lanka. use of sewage and wastewater for irrigation is common particularly among livestock farmers: as farm size in most cases is less than 1 ha. the extent of wastewater use in agriculture is difficult to estimate (Udagedara and Najim. 2009). There are past instances where farmers resisted the treatment of wastewater which is being used for agriculture. fearing that it will reduce its fertigation p0tentiaL for example. in the Tula Valley in Mexico Oimenez. 2(05). The potential of planned use of wastewater to increase the water-use efficiency and nutrient recycling is well demonstrated in countries such as Australia. Mexico. China and USA. In countries which suffer from acute water stress. such as Jordan. treated wastewater irrigation has been promoted since 1977 and today 90% of the treated waste water is being used for irrigation in this country. Israel represents a similar example. where treated waste water contributes about 40% of irrigation water demand (OEeD, 2011). However. one has to make a distinction between safe and unsafe irrigation practices regarding waste water irrigation. In India. the irrigation standards are prescribed for only a few parameters and not well implemented. particularly with regard to soil types. agro-climatic zone and nature of the agricultural produce. There is a huge lack of awareness about the risks or the potential environmental consequences of raw wastewater irrigation. Moreover. there Is no proper labelling practice for farm produce grown on wastewater or freshwater making the consumer vulnerable. Consumers or stakeholders involved in the postharvest value chain (commonly termed 'farm to fork') often remain unaware of the health risk associate