Technical and economical viability of a graywater recycling system employing an integrated preliminary settlement and filtration process

Chen Shiguang,Chen Qiuli,Zhang Yu

doi:10.2166/ws.2021.176

Chen Shiguang, Chen Qiuli + Show 1 more

Open Access

https://doi.org/10.2166/ws.2021.176

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Abstract

AbstractThe collection and reuse of graywater has become an important strategy for achieving the goal of sustainable development. In this work, an integrated preliminary settlement and filtration process was developed for treating shower water which was obtained from a college bathroom toilet. The system's pollutant removal efficiency was examined for three different filter media: manganese sand, quartz sand and ceramsite. The results showed that for ceramsite, the average removal of turbidity, CODcr, NH3-N, and anionic surfactant was 93.3%, 68.6%, 78.9, and 83.5% respectively. For manganese sand, the values were 84.6%, 61.5%, 57.8 and 59%, while for quartz, they were 88.9%, 47.9%, 39.5% and 51.9%. A cost–benefit analysis revealed that the payback period of graywater recycling systems ranges from 3.16–5.30 years and benefit–cost ratios are in the range of 1.23–1.67, depending on tank size. The proposed system provides a new strategy for enhancing water-use efficiency in buildings in a more decentralized way.

Highlights

The world is facing a serious challenge to satisfy the water demands for human activities with the increasing population, continued urbanization, and over-exploitation of water bodies (Kim et al 2007; Mandal et al 2011)
This work focuses on an innovative decentralized graywater recycling system that combines in one compact unit a settlement process and a filtration phase
The removal efficiency of the integrated preliminary settlement and filtration (IPSF) unit using three different filtering materials: manganese sand, quartz sand and light ceramsite were examined, while the economic feasibility of the proposed waste water recycle (WWR) system was assessed by benefit–cost analysis

Summary

Introduction

The world is facing a serious challenge to satisfy the water demands for human activities with the increasing population, continued urbanization, and over-exploitation of water bodies (Kim et al 2007; Mandal et al 2011). To overcome these challenges, it is necessary to adopt a sustainable approach towards water management (Bagatin et al 2014). Reuse of waste water or graywater to substitute non-potable water consumption in buildings is not a novel concept but a powerful tool for sustainable water management (Lyu et al 2016; Zhang et al 2019). For reducing the impacts of pollution on the human health, the development of effective and economic lightly polluted graywater treatment methods is required urgently (Antonopoulou et al 2013)

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Discussion

Conclusion