Anaerobic sewage treatment in a one-stage UASB reactor and a combined UASB-Digester system.
The treatment of sewage at 15 degrees C was investigated in a one-stage upflow anaerobic sludge blanket (UASB) reactor and a UASB-Digester system. The latter consists of a UASB reactor complemented with a digester for mutual sewage treatment and sludge stabilisation. The UASB reactor was operated at a hydraulic retention time of 6h and a controlled temperature of 15 degrees C, the average sewage temperature during wintertime of some Middle East countries. The digester was operated at 35 degrees C. The UASB-Digester system provided significantly (significance level 5%) higher COD removal efficiencies than the one-stage UASB reactor. The achieved removal efficiencies in the UASB-Digester system and the one-stage UASB reactor for total, suspended, colloidal and dissolved COD were 66%, 87%, 44% and 30%, and 44%, 73%, 3% and 5% for both systems, respectively. The stability values of the wasted sludge from the one-stage UASB reactor and the UASB-Digester system were, respectively, 0.47 and 0.36g CH(4)-COD/g COD. Therefore, the anaerobic sewage treatment at low temperature in a UASB-Digester system is promising.
Mahmoud
Nidal
N
Department of Agricultural, Environmental and Systems Technology, Sub-Department of Environmental Technology, Wageningen University, P.O. Box 8129, 6700 EV Wageningen, Netherlands. nmahmoud@birzeit.edu
Zeeman
Grietje
G
Gijzen
Huub
H
Lettinga
Gatze
G
D001421:Bacteria, Anaerobic / Q000378:metabolism*; D019149:Bioreactors; D007220:Industrial Waste; D012037:Refuse Disposal / Q000295:instrumentation / Q000379:methods*; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods*
D007220:Industrial Waste; D012722:Sewage