Performance of UASB rectors at different levels of sludge occupancy/sludge loading rate (SLR) when fed with low strength wastewater experiments showed the average influent CODT & CODS fed to reactor with standard deviations were 244 ± 45 mg L-1 and 162 ± 43 mg L-1 respectively.The percentage of CH4 was found to be approximately 68%.CH4 loss along with the effluent was 0.6 L d-1. The TSS and VSS concentrations in the sludge were 46.1 and 28.5 g L-1. The total and soluble COD removal efficiencies during PSS were 81.7%, and 84.7%. The OLR applied was around 1 kg COD m-3 d-1. At SLR of 0.13. The CODS removal was 88.6% & the gas production was 0.229 m3 m-3 reactor volume d-1 and it was not much affected by increasing the SLR up to 0.41. The process was upset on further increasing SLR to 0.51.The COD removal was around 81% & gas production was decreased to 0.206 m3 m-3 d-1. The volume of the sludge was reduced to 5% & COD removal dropped to 79% & gas production was also reduced considerably to 0.157 m3 m-3 d-1.The reduced efficiency may be due to heavy washout of sludge particles
