Sustainable water resources through harvesting rainwater and the effectiveness of a low-cost water treatment

Richards, S and Rao, L and Connelly, S and Raj, A and Raveendran, L and Shirin, S and Jamwal, P and Helliwell, R (2021) Sustainable water resources through harvesting rainwater and the effectiveness of a low-cost water treatment. In: Journal of Environmental Management, 286 .

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Abstract

Increases in world population and climate change are some of the pressures affecting water resources for current and future water availability. The variability in water availability can reduce agricultural yields, food supplies and potentially leads to malnutrition and spread of diseases in water-poor countries. Even some water-rich countries can experience prolonged periods of dry weather, causing a drop in water reservoirs levels, forcing more restricted water resources management. Rainwater harvesting is one key option in adapting to water shortage and future demands that may alleviate the pressure on existing water resources. This work evaluates a roof top rainwater harvesting system (RWHS) installed as part of a decentralised wastewater treatment system designed to enable a circular economy by providing a more reliable water supply system in a remote public school in rural India. The effectiveness of the RWHS in reducing the pressure on a groundwater supply was assessed along with the physical, chemical and microbial characteristics of the stored rainwater over time. Further, the application of a low-cost primary treatment to make the harvested water safe to use for multiple purposes was investigated. The results revealed that the harvested water was of acceptable quality at the start of collection, however, microbial abundance increased when the rainwater was stored for a long time without treatment. Thus, a chlorine dosing regimen for the RWHS was designed based on laboratory and field experiments. The results also demonstrated that the low-cost chlorination process was effective in the field in reducing microbial abundance in the stored water for more than 30 days. However, as the residual chlorine level was reduced with time to <0.2 mg/l in the storage vessel, the microbial abundance increased, albeit to a much lower level that meets the Indian bathing water standards. The results provide evidence that installed RWHS has reduced the pressure on existing water supply at the school by up to 25 of the water that used for washing and flushing with no treatment, and with regular chlorination, greater savings and multiple uses of the stored rainwater can be achieved. © 2021 Elsevier Ltd

Item Type:	Journal Article
Publication:	Journal of Environmental Management
Publisher:	Academic Press
Additional Information:	The copyright for this article belongs to Academic Press
Keywords:	chlorine; drinking water; ground water; hypochlorite sodium; rain, bathing water; chlorination; rainwater; relative abundance; sustainability; water availability; water relations; water resource; water supply; water treatment, Article; catchment area; catchment area (hydrology); chlorination; controlled study; cost control; disinfection; economic aspect; environmental sustainability; human; India; pipeline; rainy season; rural area; storage; waste water management; water availability; water quality; water standard; water supply; water treatment, India
Department/Centre:	Division of Mechanical Sciences > Centre for Sustainable Technologies (formerly ASTRA)
Date Deposited:	09 Dec 2021 09:28
Last Modified:	09 Dec 2021 09:28
URI:	http://eprints.iisc.ac.in/id/eprint/68503

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