Modelling Treated Laundry Greywater Reuse for Irrigation Using an Affordable Treatment Method and Seed Germination Test

Camila C A Cardoso,Ildiko Bodnar

doi:10.3390/su14031314

Abstract

A potential solution in areas facing water shortages is greywater (GW) reuse. GW is produced in bathrooms, laundry rooms, and kitchens of households. With proper treatment, it can be an alternative source for the agriculture sector, which consumes approximately 70% of the world’s water. This paper represents the characterization of synthetic laundry GW fraction (LGW), its treatment and modelling of treated LGW reuse for irrigation using a seed germination test. LGW’s constant quality (pH = 8.0 ± 0.3, turbidity = 174 ± 73 NTU, BOD5 = 300 ± 60 mgL−1, TOC = 162 ± 40 mgL−1) is suitable for testing the treatment method’s efficiency. Coagulation–flocculation, applying iron(III) chloride and sand filtration as a simple treatment combination, generates good-quality irrigation water (pH = 7.27 ± 0.23, turbidity = 0.6 ± 0.4 NTU, BOD5 = 17 ± 8 mgL−1, TOC = 16 ± 6 mgL−1). Seed germination tests with different waters, and elemental analysis of water, roots, and stems of the plants were done to verify the plants’ quality. The sodium adsorption ratio (SAR) for the raw LGW (SAR = 4.06) was above the threshold (<3) for safe irrigation, thus it is not recommended for this purpose. Based on the elemental analysis results and SAR value of treated LGW (SAR = 2.84), it can potentially be used for irrigation purposes.

Highlights

Academic Editor: Agostina ChiavolaWater scarcity is a present reality in some countries, and people all over the world can encounter difficulties in access to proper quality water for drinking purposes [1]
The sodium adsorption ratio (SAR) for the raw laundry GW (LGW) (SAR = 4.06) was above the threshold (
The analysis of the water sample was conducted via a series of analytical experiments, which include the determination of Biochemical Oxygen Demand (BOD5 ), Total Organic Carbon (TOC), pH, Zeta Potential (ZP), turbidity, and Anion-Active (ANA) Surfactant values

Summary

Introduction

Water scarcity is a present reality in some countries, and people all over the world can encounter difficulties in access to proper quality water for drinking purposes [1]. The efficient management of water resources is necessary to ensure that people have access to safe water. Goals (SDGs), the need to “Ensure availability and sustainable management of water and sanitation for all” in the SDG6, which is an initiative to encourage governments to provide good sanitation infrastructure. Alternative sources of water are important for agriculture since this sector is responsible for ca. Greywater (GW) can account for 54–86% of the wastewater produced by a household [4], and its reuse tends to become an important tool to meet the population’s need for water [5,6,7]. GW has different compositions according to its source origin, such as kitchen GW, bath GW, hand basin GW, and laundry GW (LGW)

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Methods

Conclusion