Affiliations: Department of Environmental Science and Engineering,
Zhejiang University, Hangzhou 310027, China
Abstract: This work investigated the biomass activity in a thermophilic upflow
anaerobic sludge blanket (UASB) reactor of wastewater treatment. Synthetic
textile wastewater with pH 10-11, COD level of 2000-3000 mg/L was tested.
Cellular adenosine triphosphate (ATP) in volatile solids (VS; mg ATP/gVS) was
measured and expressed as specific ATP content to compare the biomass activity
in up zone and lower zone in UASB reactor. The result shows that the specific
ATP content based on total volatile solids (VS) in lower zone (0.046 mg ATP/gVS
average) is much lower than that in up zone (0.62 mg ATP/gVS average) due to
high content of inactive biomass and high pH in lower zone. The SATP in up zone
increases as HRT increases and approaches to a maximum value of 0.85 mg ATP/gVS
at HRT of 7h, then decreases. It shows most of the total VS in up zone
represent active bacterial biomass at HRT of 7h. Rate of subtract utilization
is directly related to the activity of microorganisms in the reactor. The
effect of HRT on SATP in lower zone is not as significant as on SATP in up
zone. The buffer capacity of the thermophilic UASB reactor is very good. It is
the activity of sludge granules in lower zone that give the UASB reactor such a
good buffer capacity to the inlet high pH.