9413824 Rittmann This is a grant to support research the objective of which is to determine conditions under which monooxygenation reactions of secondary substrates can be accelerated while achieving other process goals in stable, suspended growth biological reactors that are used to treat contaminated wastewaters, leachates from landfills and groundwaters contaminated by chlorinated aliphatic and aromatic organic substances. The specific substrates the investigator plans on studying in this project are 4-chlorophenol and 2,4 dinitrophenol. A two stage process will be used in which the first reactor will be used to enrich the cells with the reduced electron-carrier and the second stage used to ensure removal of substances capable of biochemically exerting a demand for oxygen, to control growth of biomass and to provide adequate retention time for the biologically active solids. Aromatic hydrocarbons of petroleum origin, chlorinated aliphatic solvents and the nitroaromatics are the most commonly detected organic contaminants of water in the United States. Biological degradation of these compounds is an especially promising approach because, if successful, degradation is complete and likely to be economically viable under conditions that are not extreme regarding the physical conditions under which degradation takes place. Results of this project are expected to improve the design of biological reactors as they are used in environmental engineering practice. ***
