An Innovative System for Water Tank Overflow Pipes

Dec. 15, 2020
The Dechlorinating Overflow Security Assembly (DOSA) system prevents intrusion while automatically dechlorinating storage tank overflows.

Discharging chlorinated water from storage tank overflows into a stormwater system or land can be toxic and harmful to plant and aquatic life. In order to address the environmental concerns and potential regulatory penalties, Tideflex® — a division of Red Valve Company — has created an overflow and drainage pipe assembly that prevents bird and rodent intrusion, increases tank security and completely removes chlorine residual during overflow pipe and drainage discharges.

The Dechlorinating Overflow Security Assembly (DOSA) is constructed of dual Tideflex Nozzles and an internal adjustable dechlorination tube enclosed in an epoxy-coated steel or stainless-steel body.

During an overflow, the upper Tideflex Nozzle discharges an elliptically shaped jet down onto the fixed dechlorination tube. The adjustable internal tube can be rotated to different slot opening sizes to maximize removal efficiency and minimize tablet erosion. A calculated portion of the water passes through the tubes, making contact with the dechlorination tablets.

Fast and slow dissolving dechlorination tablets are available for increased adjustability. The rest of the water deflects around the tubes. The water then combines in the blending trough to ensure it has been thoroughly mixed and dechlorinated prior to discharging out of the DOSA through the lower Tideflex Check Valve.

The DOSA is available in 2- to 24-inch sizes, with some larger sizes available. A lower flanged pipe spool is optional for in-line installations.

DOSA is also available for horizontal overflow pipes. The assembly is low headloss, non-clogging and won’t freeze in cold weather. Overflow hydraulic analyses are available. WW

A division of Red Valve,Tideflex Technologies offers a full line of check valves for backflow prevention and custom-engineered systems for water mixing, aeration and effluent diffusers. To learn more, visit


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Red Valve Company

March 16, 2016