INNOVATIVE SYSTEM FOR RECYCLING OF BACKWASHING WATER IN DRINKING WATER PLANT

Abstract

THE PRESENT study focuses on the efficiency of a suggested innovative system for the treatment of the sand filter backwashing water (SFBW) in the Drinking water treatment plant (DWTP). Usually, the DWTP is consumes between 15 to 20% of their clean treated drinking water to backwashing their sand filter. Such sand filter backwashing water (SFBW) is, usually, discharged as waste. Presently, the suggested innovative system as pilot plant (PP) was employed for the treatment of SFBW. Physical and chemical characteristics of the raw Canal fresh water and the treated drinking water were extensively determined via sampling program. Meanwhile, the inlet SFBW and the treated outlet of the suggested PP were also sampled and subjected to the physical and chemical analysis. The settled particles as sludge of the PP were sand filtered. The filtered water was also evaluated in terms of the physical and chemical characteristics. The suggested PP was operated continuously where it proved efficient removal of TSS, turbidity, and aluminum at 74.1, 84.2 and 71.4%, respectively. Removal of total residue, and alkalinity reached 30.1 and 29.1%, successively. The residual Al3+ was 3.0 mg/l. Correlation between the physical and chemical characteristics of Canal water in one hand and the treated SFBW and the filtered water of the sludge on the other hand indicated that both later waters were at better quality than the former. Therefore, it was suggested to reuse this treated effluents as an additional fresh water resource to the DWTP. The advantages are: saving this wasted water, save the intial supply of water to the DWTP, and to decrease the amount of added alum to the water treatment system while protecting the Canal water from the dischrge of the SFBW that contained residual of Al3+.