A COMPREHENSIVE TREATABILITY STUDY ON ALCOHOL STILLAGE USING AEROBIC AND ANAEROBIC SUSPENDED GROWTH SYSTEMS (KINETIC CONSTANTS, SHOCK LOAD, BATCH, DATA

Scope of Study. The major objectives of the research reported here were to characterize the high-strength, acidic wastewaters that emanate as thin stillage from fuel alcohol production facilities and also to develop biological treatment kinetics and performance evaluations with both aerobic and anaerobic suspended growth systems. For this purpose, wastewaters were collected from typical alcohol manufacturing plants and subjected to pretreatment for use in the above studies for about three years. Both the aerobic and anaerobic systems were carefully operated to control growth rate and the data were collected at steady state conditions. These data were then used for evaluating treatability, and development of biokinetic constants required for mathematically modeling the treatment process.;Findings and Conclusions. From this research effort, it was found that these wastewaters are highly biodegradable and can be treated to very high degree by both aerobic and anaerobic, suspended growth systems. The Kincannon and Stover design model, that expressed substrate utilization as a function of mass loading, was capable of eliminating the scatter in the determination of biokinetic constants. In addition to substrate removal, it was observed that gas production rate and methane content of the gas were also found to be a function of applied substrate loading rate in the anaerobic system. Batch treatment anaerobic kinetics did not fit into continuous system kinetics at high F/M ratios. Nutrient shock had little impact on the anaerobic system performance. Gas production ceased completely when the feed was stopped and restored spontaneously when the feed was restarted.