Biofiltration in potatoe processing industry

Frying is a complex process as part of a potato processing industry, produces high quantities of several different volatile organic compounds (VOCs) and odour contaminated waste airs within the production of French Fries. The waste air of the frying process represents the most intensive odour nuisance, therefore the biofilter project focuses on this specific odour stream. Influencing process parameters are the chemical composition of the oil, the frying temperature in a range from 160°C to 180°C, the frying time and the potato material of the fryer. A group of VOCs includes a great number of intensive odour compounds. Fundamental laboratory scale tests are performed with synthetic frying waste air, which is produced for the simulation of a deep fat frying process. Fresh sunflower oil is heated up to frying temperature, a VOC-loading of 5 mg/l.h will be reached. Inoculations of inert filter material take place by an adapted microbial community, which origins from a former process biofilter. The determination of pollutant concentration is performed by a GC/FID analyse during laboratory scale tests. Removal capacities of more than 95% occur in laboratory reactors. Ammonium chloride is used as nitrogen source in a minimal medium, bases on a phosphate buffer, within a pH-range of 6,0-7,5 and at a temperature of 35 °C. The presence of nitrogen improves the removal efficiency enormously.