Pilot-scale demonstration of pre-fermentation for enhancement of food-processing wastewater biodegradability

A pilot-scale anaerobic/aerobic ultrafiltration system was tested to treat high-strength tomato-processing wastewater, to achieve stringent dry-ditch discharge criteria of soluble biochemical oxygen demand (SBOD) <10 mg dm−3, total suspended solids <10 mg dm−3, ammonia nitrogen <3 mg dm−3 and soluble phosphorus <0.5 mg dm−3. The anaerobic/aerobic system achieved 99.4% SBOD removal, 91.9% NH3 N removal and 100% phosphorus removal at an overall hydraulic retention time of 1.5 days and solids retention time of 5 days during the tomato canning season. Respirometric studies confirmed that the pretreatment of tomato-processing wastewater in the anaerobic reactor increased the readily biodegradable fraction, improved kinetics, and eliminated nutrient deficiency problem. Copyright © 2006 Society of Chemical Industry