Diurnal patterns of micropollutants concentrations in domestic greywater

In recent years, much interest has been given to presence of micropollutants in municipal wastewater, some of which are suspected to be endocrine disruptors, toxic or carcinogenic. Much less attention has been paid to their presence in greywater. The present research studies the diurnal patterns of micropollutants in greywater and computes their daily loads. Monitoring was carried-out using auto-controlled sampling system, designed to overcome the erratic greywater generation. Two main generation periods were identified: morning (5:00–11:00) and evening-night (18:00–2:00), contributing about 20% and >50% of daily greywater discharge, respectively. Average specific daily greywater discharge was 57 L p⁻¹d⁻¹, which matches reported value for greywater generated by showers and washbasins in Israel. The most frequently detected micropollutants in this study were methylparben (preservative), galaxolide (fragrance) and oxybenzone (UV-filter), which are common ingredients in many personal care-products. Their daily loads were 2, 840, 1, 887 and 728 µg p⁻¹d⁻¹, respectively.