2006 Fiscal Year Final Research Report Summary
Wastewater treatment under low temperature conditions by sulfur redox process and analyses of the biological consortia
| Project/Area Number |
16360269
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Civil and environmental engineering
|
|---|
| Research Institution | Kure college of technology |
|---|
Principal Investigator |
YAMAGUCHI Takashi Kure college of technology, Department of Civil and Environment Engineering, Associate Professor, 環境都市工学科, 助教授 (10280447)
|
|---|
| Project Period (FY) |
2004 – 2006
|
| Keywords | minicip al wastewater / anaerobic biological treatment / sulfur-oxidizing bacteria / sulfate-reducing bacteria / low strength wastewater / low temperature wastewater / sulfate-containine wastewater / bioreactor |
|---|
| Research Abstract |
The objective of this research is to make a novel wastewater treatment process activated by a sulfur-redox cycle action of microbe in low temperature conditions. This action is carried out by sulfate-reducing bacteria (SRB) and sulfur-oxidizing bacteria (SOB). The process was comprising of an UASB reactor as pre-treatment and an aerobic downflow hanging sponge (DHS) reactor as post-treatment. As the results of reactor operation, the whole process achieved that over 90% of CODcr removal efficiency, less than 30 mgCODcr/L (less than 15 mgBOD/L) of final effluent, at 12 hr of HRT and at 8 ℃ of UASB reactor temperature. Acetobacterium sp. was detected as predominant species by PCR-DGGE method targeting 16SrDNA with band excision and sequence analysis. In the UASB reactor, various species of sulfate-reducing bacterium, Desulfobulbus sp., Desufovivrio sp., and Desulfomicrobium sp., were found by cloning analysis. In the DHS reactor, Tetracoccus sp. presented as dominant. The proposed sulfur-
… More
redox action process was considered as an applicable process for low strength wastewater treatment in low temperature conditions.
Further more, process performance of the wastewater treatment system was investigated using a pilot-scale reactor system fed with actual sewage for over 600 days. The reactor system was consisted of a denitrification reactor, an UASB reactor, and a DHS reactor with recirculation line. As the results, the total CODcr of 331±117 mg・L^<-1> (total BOD of 128±32 mg・L^<-1>) at influent was reduced desirably to 70±33 mg・L^<-1> of DHS effluent (7±3 mgBOD・L^<-1>) at final effluent with low SS accumulation such as 2-3 % of inlet SS, on the condition of the overall HRT of 24-12 hr and the recirculation ratio of 2-0.3 throughout the experimental period. The final effluent also showed superior quality with respect to low SS, 13±6 mgSS・L^<-1> and high nitrogen removal efficiency, 58±7 % at recirculation ratio 2. Microbial activity test and FISH analysis, it revealed that sulfate-reducing bacteria contributed to degrade of organic matter in the UASB reactor even low temperature condition that it would be less than 10 ℃. Less
|
