Development of a bench scale system for anaerobic acidogenic digestion os wasterwater from isolated soy protein

Abstract

Wastewater from isolated soy protein (ISP) production is characterized by high organic load. A complex primary wastewater treatment system has been studied: an anaerobic acidogenic reactor, a tubular reactor and a sedimentation tank. Anaerobic digestion is a very complex process; the control of temperature, pH, alkalinity, TSS/VSS and COD is fundamental. The objective was to develop and compare the efficiency of a bench scale anaerobic acidogenic reactor, followed by the precipitation, coagulation and sedimentation steps, with an existing industrial ISP wastewater treatment system. The results obtained with bench system (reaction time of 6 h, 48 °C) were very close to the industrial ones: pH reduction of 4.5 to 3.7 (indicating the protein hydrolysis), high VFA accumulation (1,300 and 2,650 mg.L-1 minimum and maximum concentration), no methane production and increase in TSS/VSS. This study gives an insight of the industrial primary wastewater treatment system and can be useful in future researches.