Addressing water stress through wastewater reuse: Complexities and challenges in Bangalore, India

Wastewater reuse is an important adaptation option for mitigating water stress in rapidly growing urban centres. But, wastewater reuse is easier said than done, particularly in developing countries. The task becomes even more challenging when one takes a basin-level perspective. We illustrate these challenges by studying the Vrishabhavathy River in Bangalore, India, which carries almost half of the city’s wastewater. First, we find that the sewage treatment plant (STP) located on this river does not function efficiently and no positive impact of effluent discharge on river water quality was observed. Second, while the Sewerage Board has implemented conventional centralized sewage treatment and proposed its expansion and even larger scale projects, decentralized wastewater treatment, advocated by many civil society groups, may be more cost effective. Options at all scales, however, face several institutional challenges in implementation. Third, while untreated wastewater is a health hazard for downstream farmers using this water for irrigation, substantial wastewater recycling upstream would have a negative impact on their livelihoods by reducing the quantity of water available for irrigation. In addition, as the Vrishabhavathy is a tributary of the inter-state river Cauvery, reduced flows might impact on inter-state water sharing commitments complicating matters further. Realizing the potential of wastewater reuse in Bangalore will thus require techno-institutional integration and thinking at a basin scale.