摘要：A pilot scale study was conducted on the mesophilic (20 - 42oC) anaerobic digestion of dairy wastewater by UASB reactor, operated on anaerobic sludge granules developed from digested cow dung slurry and earthworm cultured soil. The aim of this study was to explore the effect of operational and design parameters on removal efficiency of a pilot-scale UASB reactor treating dairy wastewater. A PVC pipe with a diameter of 150 mm and total height of 103.6 cm and effective height of 79.2 cm was used as a reactor. The digestion and a 3-phase separator element had a volume of 0.014 and 0.00431 m3 respectively. The COD concentrations used in the present study ranges between 800 mg/L to 4080 mg/L while the BOD concentrations ranges between 384 mg/L to 1880 mg/L. The digester efficiency of treating dairy wastewater at various HRT of 6, 12, 24, 48 and 72 h and OLR corresponding to HRTs were 2.77, 2.16, 1.574, 1.052, 0.54 kg COD/m3d and 1.276, 0.995, 0.741, 0.515, 0.261 kgBOD/m3d respectively, at 0.0224 m/h upflow velocity was studied and its performance was assessed by monitoring pH, BOD5 and COD. During this study, which lasted for 44 days, no heat exchanger was used and pH was maintained between 7.1 to 7.7. Finally the COD concentrations of the UASB reactor effluent with optimum HRT of 48 h and OLR of 1.052 kg COD/m3d was obtained 557 mg/L corresponding to treatment efficiency of 64%. While the BOD concentrations of the UASB reactor effluent with optimum HRT of 48 h and OLR of 0.515 kgBOD/m3d were obtained 202.6 mg/L, corresponding to treatment efficiency of 73.3 %. At the end of experiment, a granular sludge with good settling properties was produced.
关键词：Anaerobic digestion; Dairy wastewater; UASB; OLR;HRT; Ambient temperature
