THE EFFECT OF TEMPERATURE ON THE EFFICIENCY OF AEROBIC BIODEGRADATION OF SUGAR BEET DISTILLERY STILLAGE: REMOVAL OF POLLUTION LOAD AND BIOGENS

摘要

Beet stillage is a high-strength effluent from the production of ethanol from sugar beet. A large annual volume of sugar beet stillage requires finding new effective ways for its utilization. The aim of the study was to investigate the effect of temperature on the efficiency of aerobic biodegradation of beet stillage. Biodegradation was carried out for 168 hours in a stirred-tank reactor with a working volume of 5 L at 27 degrees C, 36 degrees C, 45 degrees C, 54 degrees C and 63 degrees C. All experiments were performed at uncontrolled pH, aeration of 1.0 vvm and of 900 rpm. The effectiveness of biodegradation was determined by the extent of removal of SCODsum (COD determined after suspended solids separation and theoretical COD of betaine), BOD5 and TOC. Studies have shown that, under mesophilic conditions, the extents of reduction of SCODsum, BOD5 and TOC were statistically significantly (p <= 0.05) higher than under thermophilic conditions. Within the range of 27-36 degrees C, the highest reduction in SCODsum (79.2-79.9%), BOD5 (98.4-99%) and TOC (76.1-77.3%) was obtained. Additionally, at the temperature of 36 degrees C, the highest reduction in total nitrogen (56.4%) and total phosphorus (58%) was achieved. Aerobic biodegradation allows for efficient treatment of sugar beet distillery stillage (preferably at 36 degrees C).