Quantitative assessment of residential water end uses and greywater generation in the City of Al Ain

Abstract

Diversification of water sources and water demand reduction are two vital tools in maintaining the security of urban water supplies in the United Arab Emirates (UAE). Reuse of greywater for non-potable end uses can be an effective alternative, but this resource has not yet received much attention in the UAE. Since the generation of greywater significantly differs from country to country – depending on age, gender, habits, lifestyle, living standards and the degree of water abundance – an attempt was made to estimate internal water consumption and greywater generation in the city of Al Ain, UAE. The frequency and water requirement for personal water uses (e.g. showers, ablutions, teeth brushing, hand washing, face washing and toilet flushing) and family water uses (e.g. laundry, dish washing and house cleaning) were estimated from about 100 villa-type detached homes randomly distributed across the city. A frequency analysis was carried out using normal, lognormal, gamma and logistic distribution. The estimated average generation rate of greywater was found to be 192 litres per capita per day, which is about 69% of the average internal water consumption. The generated greywater originates from showers (49%), ablutions (18%), laundry (10%) and washbasins (23%). Based on average quantities, it was shown that the generated greywater is sufficient to fulfil the non-potable water demand in houses, but further, more rigorous, investigation is required.