Biomethanation of cheese whey using an upflow anaerobic filter

The feasibility of cheese whey treatment by an upflow anaerobic filter (UAF) was tested. The effect of hydraulic retention time (HRT) (1, 2, 3, 4 and 5 days) and the feed concentration (5, 10, 15 and 20 g COD/1) on the extent of the degradation of this wastewater was examined. Varying the HRT from 5 to I day at 35degreesC had no effect on the fermentation stability and pH remained between 6.83 to 7.34. The performance of the reactor was depressed by changing the feed concentration from 15 to 20 g COD/l. The average total COD removals achieved was 80-90%. Physico-chemical pre-treatment using floculation and decantation were used to remove the fats and the suspended solids through the decanter and then to reduce the organic matter concentration. 50% of COD concentration was removed and the pre-treated effluent was used to feed the UAF reactor. Lactobacillus paracasei ssp paracasei 1 which was isolated from cheese whey showed higher acidification efficiency and can be used to enhance the acidification step in a separated reactor.