| Abstract |
| This study was performed to find out the characteristics of microorganisms affect the volume reduction ratio(VRR) of sludge. This study can be divided into two main categories. The first experiment compared the values of VRR and microbial species characteristics of microorganisms in a sewage treatment plants(STPs) under three different operating conditions. The second experiment evaluated the effect of extracellular polymeric substances(EPS) on VRR efficiency. The microorganisms that were collected from three types of STPs were first classified into samples according to their concentration. Subsequently, the VRR values were compared by adding two types of activated carbon powder(M I 125~250 ㎛, M II 250~425 ㎛) as a weighted additives. As a result, it was found that a large VRR was achieved for a range of mixed liquor suspended solids(MLSS) 3,500~6,400 mg/L, regardless of the characteristics of the microorganism, due to the weighted additives. In contrast, it was shown that the VRR of microorganisms with a long sludge retention time(SRT) rapidly decreased for concentrations exceeding MLSS 5,500 mg/L. As an important operating parameter for STPs, it has been considered that SRT determines the EPS concentration of microorganisms within the process. As a result of analyzing the EPS of two types of microbial samples with different SRT, it was shown that the concentration of EPS was low in the case of the sample with long SRT, and the concentration of EPS was high in the case of the sample with short SRT. All the results revealed that to improve microbial settleability using weighted coagulation technology, it is desirable to use it in the range of MLSS 3,500 to 5,500 mg/L, or apply it to STP with short SRT under the higher concentrations of MLSS 5,500 mg/L. |
|
|
| Key Words |
| Extracellular polymeric substances, Sewage treatment plants, Sludge retention time, Volume reduction ratio, Weighted coagulation, 세포외고분자물질, 하수처리장, 슬러지체류시간, 용적감용율, 가중응집 |
|
|
|
|
|
PDF