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Effect of Pollution Load and Oxygen Availability on Thermophilic Aerobic Continuous Biodegradation of Potato Processing Wastewater

2007; Wiley; Volume: 7; Issue: 2 Linguagem: Inglês

10.1002/elsc.200620181

1618-2863

M. Lasik, J. Nowak,

Water Quality Monitoring and Analysis

Abstract The possibility of enhancing the effectiveness of the biodegradation process of potato wastewater was evaluated. The effect of wastewater pollution load, dilution rate and oxygen supplementation during the thermophilic aerobic continuous utilization process on biodegradation of the main organic pollutants was investigated. Aeration performed using a stirred tank reactor (1.5 vvm, 300 rpm, 55 °C) proved to be not sufficient to provide aerobic conditions. During the continuous process, the amount of oxygen introduced into the wastewater was totally utilized by the microflora. The accumulation and decomposition of the fermentative metabolism products of the Bacillus mixed culture during oxygen limitation and supplementation were analyzed. Under microaerobic conditions (DOT < 1 %), a biosynthesis of acetic acid was observed up to a concentration of 6.5 g/dm 3 . After chemostat conditions were achieved, the level of acetic acid stabilized at 2.2 g/dm 3 . The addition of oxygen for aeration allowed a total decomposition of organic acids like acetic and lactic acid (the by‐products were synthesized from partially oxidized substrates) as well as an increase in COD reduction of the wastewater (from 66 % to 79 %). The periodic fortification of aeration with pure oxygen is proposed for critical situations during the continuous wastewater biodegradation when an unexpected inflow of highly polluted wastewater occurs in the system.