Biological treatment of corn processing wastewater with converting its organic compounds to nutritive substance
2001
Hagh Nazary Simin (Mashhad Univ. (Iran). Dept. of Food Science and Technology)
In one of the corn starch producing plants in Iran, approximately 23 tons of organic materials are left out daily in wastewater. This wastewater, in addition to its illegal contamination for discharging into city effluent system would cause microbial growth due to its nutritive materials leading to spread of microbial contamination in process line and products in the factory. In order to solve the above mentioned problems, also to get the benefit of nutritive substances of wastewater in the said plant for the production of a valuable byproduct so called "SCP" to be used as protein supplement in animal, poultry and fish feed; the wastewater was treated by biological methods regarding the reduction of maximum chemical oxygen demand (COD) in lab scales. After elimination of suspended solids from the wastewater by centrifugation, the purified wastewater was fermented under various conditions: 1 - PH; "3.5", "4.5" and "4" without controlling, 2- Temperature "25" and "35" degree centrigrade. 3 - Fermentation with "mixed-cultured" and "mono-culture" of wastewater microflora. 4 - Addition/no addition of % 6.7 glucose. 5 - Fermentation in incubation shaker unit with controlled heating. Samples were taken in 4 hours intervals, the amount of COD reduction and produced biomass in different samples were measured during 72 hours. The best condition for fermentation found to be at PH = 4 with no control, the temperature of 35 deg C using mixed-cultured and without addition of glucose. The results of this research can be used at the aerobic condition in the large scale fermentor, so that its effect will be distinguished
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