Abstract: A method and apparatus for removing select gas contaminants is disclosed. The apparatus is a bioreactor having a chamber for containing liquid and a liquid positioned therein, the liquid forming a column having a top and a bottom surface defining a height. The bioreactor further has a gas dispersal unit positioned in the column and a selected biomass suspended in the liquid, where the biomass is selected to metabolize the gas contaminant requiring degradation. The method includes feeding a select gas contaminant having a low Henry's coefficient into the gas dispersal unit to produce a stream of bubbles containing the gas contaminants, where the gas contaminant is a food source for said biomass, and allowing the stream of bubbles to sparge through and exit the top of said column.

Abstract: A method for treating municipal wastewater in an oxidation ditch activated sludge system by automated determination of the nitrogen depletion inflection point, which enables anoxic cycles to be utilized to achieve improved settling of the activated sludge by providing selective pressure against the growth of filamentous bacteria, by providing improved total nitrogen removal, by providing energy savings and by providing recovery of alkalinity.