Treatment and effective utilization of greywater

Abstract

Sustainable management aims at the governance of natural resources to meet the needs of future generations. The limited resources of freshwater in arid regions have led to the development of alternative water management strategies. To meet the future challenges of water scarcity, an attempt has been made in this study to utilize treated greywater obtained by gravity-governed filtration technique and disinfection for domestic usage. The study addresses the possibilities of groundwater recharge with the treated greywater. The method focuses on a gravity-governed flow through a column containing activated carbon, sand and gravel. The greywater used for the treatment contains a mixture of equal proportions of water collected from three different sources such as kitchen sink, shower and washing machine in Fahaheel, Salmiya and Farwaniya areas of Kuwait. The study concluded that for a volume of 1167 cm3 filtration media used, the designed column was 34% effective for first 1100 mL of greywater. Later, the column was regenerated by washing with distilled water and the regenerated column still proved to be effective with a removal efficiency of 26% for next 600 mL of greywater. The quality of the treated greywater was assessed in terms of physical, chemical and microbiological parameters as per the standard methods to check the suitability for domestic purposes. The results obtained were also compared with the groundwater quality of Kuwait group and Dammam aquifers, and it was inferred to be at par with their quality. The TDS of treated greywater has been reduced from 4910 to 1508 mg/L, which is also lower than the TDS in groundwater of both the aquifers, and pH was reduced from 10.29 to 7.94. The present study proved its efficiency equally to other existing methods, and the efficiency of removal for some of the analyzed parameters was measured as 23%, 95%, 52%, 88%, 100% and 100% for pH, color, TDS, turbidity, total coliform and E. coli, respectively. Hence, the study is simple and cost-effective approach that can be adopted for the treatment and reused greywater for domestic and agriculture and also for recharging the aquifers to prevent saltwater intrusion along the coastal aquifers.