Generation and Quality Analysis of Greywater at Dhaka City

Abstract

One of the natural resources available in nature is water; however, it is not readily available for domestic use for millions of people across the globe. An increasing global population coupled with growing urbanization worldwide has led to increased demands on water supply. The rapid growth of water-intensive agriculture in developing countries and inefficient water management practices in the developed world are contributing to a global reduction in future freshwater supplies. The world is currently in the midst of cross roads where the unsustainable and impractical uses of water are no longer acceptable. The recycling and reuse of water is therefore imperative in some areas, and increasingly such in the others to meet the demands for urban, industrial and agricultural water requirements. Greywater, which can be defined as all in-building wastewater streams with an exception of toilet wastewater, is a potential water source for urban reuse, as it contains a few or no pathogens and 90 percent less nitrogen than blackwater. This study reveals the generation and quality of greywater in Dhaka City. The groundwater level is depleting by 2/3 of a meter per year in Dhaka. Thus, the recycling and reuse of water have become imperative to meet the demand for it. To analyze the generation of greywater in Dhaka City, water use in five households has been studied and about 67% of water was found to be reusable, whereas about 17% of potable water was wasted in toilet flushing. From the quality analysis, kitchen water was found to be polluted to some degree, and judging by its quality, it should not be reused. Greywater must be treated before any kind of reuse as it exceeds the standards of the acceptable quality of potable water and irrigation water.

DOI: http://dx.doi.org/10.5755/j01.erem.64.2.3992