Sujinda Natpinit, Preecha Ploypatarapinyo, and Pitsamai Jenvanitpanjakul

pp. 217 - 226

Abstract

The objective of this investigation was to treat the high strength protein wastewater by UASB system. The wastewater of this experiment had COD 2,938 mg/l, SS 478 mg/l and total of nitrogen 435 mg/l. The granule was developed from bacteria of activated sludge system as suspended sludge by fermenting anaerobically at 40ºC for 1 month and acclimatizing with the high strength protein wastewater for another month. The MLSS and MLVSS of the started bacterial sludge were 7,105 mg/l and 5,360 mg/l respectively.
The maximum organic volume loading of this system was 6 kg COD/m³.d at the hydraulic retention time 12 hrs. The efficiency of COD and BOD removal was 88.38 and 93.07% respectively. The biogas production was 0.52 l/g COD_r.d. The content of methane gas was 76.20%. The bacterial suspended sludge was developed to granular sludge with the granule's size of <0.25 mm, 0.25-0.5 mm, 0.5-1.0 mm and >1.0 mm as 86.02%, 2.05%, 11.84% and 0.09% respectively.