Facets of cost-benefit analysis of greywater recycling system in the framework of sustainable water security

Considering the rising constraints of freshwater supply, alternative options like reuse of treated greywater must be investigated. Year-round availability and biodegradable organic content of greywater make it a viable source of water for recycle and reuse supplementing water supply especially in water -stressed areas. Greywater reuse warrants installation of a treatment plant and supply infrastructure, both of which require financial resources. Unfortunately, there is no uniform method for performing cost -benefit analysis (CBA) that considers the local context but still is applicable to all reuse applications. The present work critically analyses the overall greywater characteristics and evaluates the efficacy of various physicochemical, biological, and advanced treatment methodologies for enhancing its quality, with the ultimate aim of promoting its safe and sustainable reuse. This article addresses several ways for CBA of greywater management and illustrates them with examples. Appropriate CBA techniques can be used as a tool for better understanding the economics of wastewater management as well as cost evaluation to rationalize appropriate investment option in this sector. Aspects of economic analysis and economic feasibility study are also considered for total economic evaluation as it can provide useful information for improving the greywater management and, further, help integrating the environmental and health advantages.