Decentralized water reuse planning: Evaluation of life cycle costs and benefits

Abstract

The objective of this paper is to comparatively evaluate the life cycle costs and expected monetary benefits of decentralized greywater reuse systems. Specifically, added life cycle costs and estimated life cycle monetary benefits of satellite and onsite greywater reuse systems are evaluated in comparison with the prevailing centralized systems. Centralized systems refer to the traditional form of water delivery where one centralized treatment plant treats and distributes potable water to a large service area through a water distribution network while a sewer network collects used water for treatment at a centralized wastewater treatment plant before the wastewater effluent is disposed into the environment. Satellite greywater reuse systems collect raw greywater at neighborhood or district level for treatment and re-distribution for non-potable uses within the same neighborhood or district. Onsite greywater reuse systems collect raw greywater for treatment on the premises of where it is produced after which it is re-distributed for permitted non-potable use on the same premises. Infrastructure needs and associated life cycle cost information for both types of greywater reuse systems are appropriately modeled or synthesized from literature. The skeletal layout of a real-world water distribution network is adapted for performing the cost-benefit analysis in this study. Finally, sensitivity of the cost-benefit tradeoff associated with satellite and onsite greywater reuse adoption scenarios is evaluated for various uncertainties associated with technological evolution, policy incentives, and planning schemes. Given that several states in the U.S. are expected to face water shortages in the near future, this paper will provide guidance to water utilities and policy makers in planning of future water supply alternatives.