Water Board Saves 18 MGD Of Water, Cuts Krishna Pipeline Shutdown Time By 12 Hours

A new pipeline interconnection by the Hyderabad Metropolitan Water Supply and Sewerage Board (HMWSSB) has helped save 18 million gallons of treated drinking water during a recent shutdown of the Krishna Phase-II main pipeline, while cutting the time needed to empty the pipeline from 20 hours to eight hours.

The system was implemented at the Nasarlapally Pumping Station by linking the Krishna Phase-I, Phase-II and Phase-III main pipelines. During the Phase-II shutdown, around 23 MGD of water was available in the pipeline. Instead of releasing most of it through the scouring system, 18 MGD, or nearly 80 per cent, was diverted to the Phase-III reservoir and used for drinking water supply.

Only around 5 MGD had to be released through scouring, helping reduce treated water wastage during maintenance work. The shorter scouring time also resulted in savings of more than 12 hours in the overall shutdown period and around Rs.5 lakh in electricity costs.

The interconnection was created at Nasarlapally by connecting three 2,375-mm diameter main pumping pipelines of Krishna Phases I, II and III to their respective clear water reservoirs through a 600-mm diameter interconnection pipeline.

The need for the system arose along the nearly 24-km pipeline stretch between Nasarlapally and Godakondla. Rapid construction and development along the route had affected the functioning of existing scouring arrangements at several locations. This meant that more time was required to empty the main pipeline during shutdowns, resulting in the loss of treated water.

HMWSSB Managing Director Ashok Reddy said the new arrangement provides an alternative way to manage the water remaining in the pipeline before maintenance work. Its use during the recent Phase-II shutdown showed that a significant portion of the water could be retained within the supply system and put to public use instead of being released through scouring. 

The shutdown was also used to replace 48 air valves connected to the main pipeline. HMWSSB said the maintenance works were completed quickly and water supply was restored in record time.

Reddy also said the Nasarlapally system can help reduce treated water wastage and electricity consumption, cut shutdown periods and enable faster restoration of water supply. 

Following the results, HMWSSB is examining similar interconnection systems at Godakondla, Kodandapur and other suitable pumping stations. Such systems could help reduce water losses during future maintenance shutdowns and improve the reliability of drinking water supply to Hyderabad.