Sequential disinfectant treatment for waste water

Abstract From the Canadian patent

A method and apparatus for sequentially dosing waste water with a disinfectant at a plurality of spaced locations along a flow path (15) such as within a , contact tank (10). Dosages of disinfectant introduced at each location are proportioned or graded such that the dosage at each location is less than the dosages delivered upstream therefrom. The graded dosing provides a level of disinfectant effective to destroy or otherwise render harmless microorganisms in the waste water and minimize the residual disinfectant remaining at the end of the flow path while employing a lesser total amount of disinfectant in comparison to conventional, single-dosage techniques.