ENGINEERING JOURNAL CHIANG MAI UNIVERSITY

Volume 26, No. 03, Month DECEMBER, Year 2019, Pages 214 - 223

Effect of ph on acidification of whey, yeast and yolk wastewaters

Pacharawan Hanjai, Somjai Karnchanawong and Seni Karnchanawong

Abstract Download PDF

The acidification of protein wastewaters was investigated under different operational pH values (4.14 – 7.09) at ambient temperature. Synthetic whey, yeast and yolk wastewaters were used as the substrates. Three lab-scale continuously stirred tank reactors (CSTRs), each with a working volume of 2 L, were employed as acidogenic reactors. They were operated at a hydraulic retention time (HRT) of 4 h with a substrate concentration around 2 gCOD/L, corresponding to organic loading rates (OLRs) of 12.9 – 14.7 gCOD/L‧d. Whey wastewater was the most sensitive to pH with the maximum acidification efficiency of 30.9% and acidification rate of 3.88 gCOD/L‧d at pH 4.14. The highest acidification efficiency and acidification rate of yeast wastewater were found in neutral pH range (7.09) at 4.6% and 0.52 gCOD/L‧d, respectively. Yolk wastewater was better acidified in slightly acidic condition (pH 5.52) with the maximum efficiency and rate at 4.6% and 0.38 gCOD/L‧d, respectively. When comparing the system performance with no pH control condition of each wastewater, pH adjustment is not necessary. The results of this study confirmed that pH adjustment cost could be saved in the acidogenic CSTR of the two-phase anaerobic treatment of the protein wastewaters.

Keywords

Acidification efficiency, Acidification rate, CSTR, pH, Whey, Yeast, Yolk

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