AWWA ACE61673 "TANK VAC" Technology Improves Rainwater Quality through Automatic Tank Flushing

Conference Proceeding by American Water Works Association, 06/17/2005

Walmsley, M.R.W.; Agnew, W.; Wickham, W.D.

Full Description

This paper describes a new rainwater tank cleaning system called "Tank Vac" which aids theregular removal of debris and sludge from the bottom of water storage tanks. The system relieson overflowing water from the bottom of the tank rather than the top using a unique siphonsystem. When the tank is full, a valve in the overflow line is triggered to allow waterfrom the bottom of the tank to flow out the overflow pipe at a rate high enough to produce afull siphon. The magnitude of the flow creates a cleaning action at the base of the tank. Aftera short flush period, a ball cock allows air into the line to break the siphon and the cleaningaction ceases until another high rainfall period. "Tank Vac" installations in household rainwatertanks have decreased E.coli levels at the bottom of the tank from 430 counts per 100mlto zero after a 4 month period and increased oxygen concentration levels markedly. A "TankVac" flush model is described for predicting the flush frequency over a calendar year for agiven set of conditions; such as local rain fall, tank size, roof size, collection efficiency andhousehold water use rate.

Product Details

Edition: Vol. - No. Published: 06/17/2005 Number of Pages: 5