|
Environmental Engineering Research 1997;2(3): 191-200.
|
Effects of hydraulic retention time on the anaerobic digestion of thickened excess
sludge by sulfite in the two phase digester
|
Jae-Kyung Yang1†, Kyung-Min Choi1, Sung-Taik Lee1, and Tadahiro Mori2 |
1Department of Biological Science, Korea Advanced Institute of Science and Technology, Taejon, 305-701, Korea 2Institute of Midorito Mizu, Kohukudai 5-9-4, Abiko city, Chiba Prepecture, Japan |
Corresponding Author:
Jae-Kyung Yang , |
Received: May 12, 1997; Accepted: July 13, 1997. |
|
Share :
|
ABSTRACT |
Sulfite was added into the anaerobic digester in order to accelerate the solubilization step of thickened excess
sludge and to increase the activity of sulfite reducing bacteria (SRB). However, under the high sulfite adding condition, VFAs such as acetate were accumulated due to the increment of hydrogen partial pressure, free hydrogen sulfide and free ammonium by the decomposition of solids like protein in the single phase. Two-phases continuous anaerobic digester was adopted to prevent the inhibition effect associated with the accumulation of VFAs or free hydrogen sulfide. The optimum hydraulic retention time (HRT) were determined as 3 days in the acidogenic phase, and in the methanogenic phase 12 days respectively. Maximum methane production was 30μmol • g-VS-1 • d-1, and maximum decomposition efficiencies of VS and COD were 55 % and 54 % of input values at the optimum HRT, respectively. The microflora was changed to the methanogenic state at over 3 days of HRT and over 12 days of HRT in the methanogenic phase. The increment of biogas production was not observed over 12days of HRT.
|
Keywords:
Sulfite | Hydraulic retention time | Two-phase digester | Thickened excess sludge |
|
|
|