The effluent from UASB reactor often contains residual COD and TSS that must be
further reduced through post treatment so as to meet effluent disposal standards. In this
study, Effective Microorganisms (EM) consortium was inoculated at the ratio of 1:500 in
the UASB reactors to ascertain its impact on improving removal efficiency of both COD
and TSS. Laboratory scale UASB reactors with effective volume of 4L made of PVC pipe
with internal diameter of 100mm were used. Three experimental set-ups were organized
and operated for 60 days to investigate not only performance of the reactor but also to
investigate the best configuration for EM consortium inoculation. Set-up A comprised of
two individual reactors without and with EM (R1 and R2 respectively); Set-up B (R2*) and
Set-up C (R3) both comprised of two sequential reactors where EM consortium was
injected at the inlet of the second reactor and first reactor.