Automated Dosing of Hydrogen Peroxide Based on Real-Time Hydrogen Sulfide Measurements in an Aerated Sludge Holding Tank and Belt Filter Presses at the Norfolk, Nebraska Water Pollution Control Plant

摘要

This paper summarizes the method developed to control hydrogen sulfide (H_2S) levels within an aerated and mixed sludge holding tank and the belt filter presses at the Norfolk, Nebraska Water Pollution Control Plant from 2014 to 2018. The average plant loadings are 69% industrial and can be highly variable, which leads to varying sulfide generation rates. Sludge is typically stored within the holding tank for one to three days before dewatering at belt filter presses. While much of the time the holding tank aerators minimize sulfide generation rates, nonetheless problematic concentrations of H_2S are often found within the holding tank and at the belt filter presses. Automated dosing of hydrogen peroxide (H_2O_2) into the holding tank and prior to the belt filter presses based on real-time H2S measurements was implemented. This maintained target H_2S levels while dosing only when it was needed, while allowing the plant to avoid having to replace a wet scrubber and recommission a hydroxyl ion generating unit.