Clogged Opa filters hit water supply briefly

Ponda: Water supply to Tiswadi and Ponda was interrupted on Thursday due to clogged filters at Opa Water Works that provide drinking water to both talukas. It was restored later in the evening after the filters — which had got clogged due to high river turbidity amid incessant rain over Wednesday and Thursday — were cleaned. Opa had recorded 168NTU (nephelometric turbidity unit) of turbidity on Thursday morning. Water containing 1mg of finely divided silica per litre has a turbidity of 1NTU. Up to 50NTU is considered normal, said assistant engineer at the drinking water department, Sunil Kerkar. High turbidity levels mean the staff have to clean the filters repeatedly as these quickly become non-functional due to the density of water sediments. On an average, about 150 cubic litres of water are used to backwash each filter, said Kerkar.