WaterReuseLab

The WaterReuseLab project aims at analyzing whether and how a new generation of high-quality decentralized wastewater reuse systems could be developed in Bengaluru, India and scaled up to other cities in India and beyond.

The WaterReuseLab project aims at analyzing whether and how a new generation of high-quality decentralized wastewater reuse systems could be developed in Bengaluru, India and scaled up to other cities in India and beyond. In close collaboration with research partners and local stakeholders, the project assesses technologies, water quality monitoring approaches, business models, user acceptance issues and governance models that taken together could help create water reuse solutions ‘that work’ in addressing complex water challenges of booming megacities.

A water tanker being filled in Bengaluru, Karnataka, India.

Background

Providing a growing urban population with safe and affordable water is a key sustainability challenge of our time, especially in the booming megacities of low-and middle-income countries. Decentralized water treatment and reuse systems (DWTRS), which treat wastewater onsite and enable water reuse directly within buildings or in construction sites, laundries or public parks in the neighborhood offer a flexible and drought-resilient solution. However, few cities have successfully implemented DWTRS at scale, and research on how technological and social factors jointly influence the performance of this innovative water management approach is still scarce.

The WaterReuseLab project addresses this gap by exploring the development of DWTRS in Bengaluru, India—a case study exemplifying water and sanitation challenges in rapidly growing megacities. The project applies a socio-technical systems perspective for identifying success conditions for creating reliable, acceptable, affordable, and scalable DWTRS solutions. It will provide a holistic assessment of DWTRS development potentials and barriers and analyze how shifts in context conditions, incentives, and actor strategies impact the emergence of a new template for urban water management in Bengaluru. Additionally, the project will examine how local coalitions can navigate various development scenarios and how solutions developed in Bengaluru could diffuse into other Indian cities and beyond.

 

Project Structure 

The project builds on intensive inter- and transdisciplinary exchanges among researchers from various Eawag departments, CDD, as well as practice partners in Bangalore and Switzerland. Our research questions and outputs are defined and refined through constant interactions with partners and through a series of stakeholder workshops organised across the full duration of the project.

Work Package 1: Technology

Work Package 1 focuses on developing technologies and strategies for effective on-site wastewater treatment to ensure quality and microbial safety of treated wastewater for non-potable reuse. This includes the operation of membrane-based ultrafiltration systems and integration of simple sensors for online monitoring and control, with the goal of achieving a low-cost and robust treatment solution. Further, pathogen concentrations will be determined in existing systems by conducting a microbial risk assessment and establishing appropriate removal targets and treatment configurations.

Work Package 2: User Acceptance

Technological advancements and the creation of viable business models to increase on-site wastewater treatment and reuse can only be successful if they are accepted by users. Work Package 2 investigates the determinants of user acceptance. For example, we are interested in how different technological configurations (e.g. real-time monitoring of the water quality or differences in reuse purposes), different business models (e.g. on-site reuse vs. selling the water for off-site reuse), and different contextual factors (e.g. high or low water scarcity) relate to changes in user acceptance.

Work Package 3: Business Models

Work Package 3 analyses how new business models can be created that guarantee reuse while providing local businesses and residents with tangible financial, ecological and social benefits. Based on surveys with end users, expert interviews and a series of stakeholder workshops, we will conduct a comprehensive system analysis and identify trajectories for scaling high-quality solutions for on-site and off-site water reuse.

Work Package 4: Governance

Work Package 4 aims to conduct a comprehensive study on the governance framework surrounding decentralized wastewater treatment and reuse, encompassing policies, institutional structures, and regulatory mechanisms. The analysis identifies gaps between policies and practice. Ultimately, it provides actionable recommendations to establish a functional reuse value chain.

Work Package 5: Stakeholder Interaction

We are conducting research on and promoting the adoption of decentralised wastewater treatment and reuse in Bengaluru for improved water security through mapping existing decentralised sewage treatment plants, identifying commercial and industrial demands and interviews with RWAs. We are also building and anchoring stakeholder relationships by bringing actors from the government, civil society organisations, RWAs, industries, and startups together to co-create strategies ranging from policies and guidelines to outlining design requirements for new technologies to boost wastewater reuse in the city.

Point of Contact

Shreya Nath

Managing Partner, Urban Water

Publications

Narayan, A. S.; Dorea, C.; Willetts, J.; Friedman, L.; Kalbar, P.; Chandran, K. (2024) A portfolio approach to achieving universal sanitation, Nature Water, 2(11), 1044-1047, doi:10.1038/s44221-024-00336-0

 

Kollmann, J.; Nath, S.; Singh, S.; Balasubramanian, S.; Reynaert, E.; Morgenroth, E.; Contzen, N. (2023) Acceptance of on-site wastewater treatment and reuse in Bengaluru, India: the role of perceived costs, risks, and benefits, Science of the Total Environment, 895, 165042 (11 pp.), doi:10.1016/j.scitotenv.2023.165042

 

Reynaert, E., Nagappa, D., & Morgenroth, E. (2023). Research brief: using sensors and automated chlorination to improve the microbial water quality of on-site sewage treatment plants in Bengaluru. doi:10.3929/ethz-b-000603755