The specific objective of this study is to evaluate the performance of UASB reactor in dairy manure wastewater. The experiment was conducted at four COD Ioading rates, and with two amount of granule seeded. Based on statistical analysis of data from this experiment the following conclusions were given:
    The increase of biogas and methane gas production were observed with the increase of the COD Ioading rate, the results appeared to show a linear relationship between the COD Ioading rate and the biogas and methane gas production.
    At a COD Ioading rate of 1.35 g/L/day, the UASB reactors effectively removed 94 - 95 % of COD from the dairy wastewater, then the COD removal capacity of the UASB reactors gradually declined with the increase of the COD loading rate.
    The performance of Reactor A, seeded with 500 mL of granule was able to achieve higher COD removal and higher methane gas production at all COD Ioading rates than Reactor B, which was seeded with 250 mL of granule. The amount of seed granule used is an important parameter in reactor performance of UASB reactors.

Keywords: UASB, Upflow anaerobic sludge blanket, dairy manure, Methane, Biogas