AUTOTROPHIC DENITRIFICATION USING SULFUR ELECTRON DONORS.

This research project investigated the feasibility of autotrophic denitrification as a nitrate removal process for municipal wastewater. The overall objective of this project was to evaluate the microbial kinetics, and to assess the process performance of autotrophic microbially mediated denitrification using sulfur electron donors. This study was divided into three experimental phases. Each phase utilized a different sulfur compound or flow configuration. Included in these phases were: continuous flow slurry-type with elemental sulfur as the electron source; semicontinuous flow, complete-mix reactors with thiosulfate or sulfide as the electron source; and packed bed columnar reactors with elemental sulfur as the electron source. Based on theoretical and experimental considerations, kinetic models and stoichiometric relationships were developed for the autotrophic denitrification process. The results of this study indicate that autotrophic denitrification with various sulfur species, particularly elemental sulfur, is a feasible scheme for removal of nitrate from wastewater effluents.