CONCEPTS FOR MINIMIZING EMISSIONS AT ACTIVATED-SLUDGE PLANTS

In the next few years, the need to decrease emissions of odors and volatile organic compounds will become increasingly important in the design and operation of wastewater treatment plants. The primary methods for decreasing emissions are adding precipitating chemicals to raw wastewater, using velocity-controlled or vortex-type grit chambers, eliminating or decreasing free falls, covering tanks and channels, decreasing stripping in aeration tanks, minimizing chlorine use, operating treatment plants properly, and collecting and treating vented air. The methods cannot all be used simultaneously at a single treatment plant, and some of them might prove to be too costly, except in special circumstances. Nevertheless, they are worth considering.