| Abstract |
| The purpose of this study is to understand the dewatering characteristics of sewage sludge and nightsoil sludge using diatomite precoted filtration. Diatomaceous earth, a natural material, was used as a filtration material for sludge dewatering, thereby minimizing the inhibiting factors of the subsequent composting process. As a modifier for dewatering, the heavy metal component of chemical agents is sometimes a factor in degrading quality in composting processes and fertilizer products. The independent variables in the pre-coating diatomite filtration experiments of sewage sludge were filtration time(min) and vacuum pressure(mmHg). The vacuum pressure was 420 mmHg to 600 mmHg and the filtration time was 19 minutes to 25 minutes. Experimental design was performed using response surface methodology. Diatomaceous earth was fixed at 50% in the experiment for optimum mixing ratio of diatomaceous earth and adjuvant, and the amount of oyster shell powder, dolomite and charcoal powder was changed to the remaining 50%. The results of the mixture analysis were analyzed using Minitab 15, a statistical program. The dewatering characteristics of sludge were as follows: the vacuum pressure was higher and the longer the filtration time, the lower the moisture content and the higher the removal rate of TN and TP. Moisture content was 63%, TN removal efficiency and TP removal efficiency were 68% and 91%, respectively. According to the results of experiment for optimum mixing ratio of diatomite and added material for manure sludge filtration, moisture content was lowest and TN and TP and BOD removal efficiencies was highest at oyster shell powder: dolomite: charcoal powder: diatomite mixture ratio 17: 25: 8: 50. |
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| Key Words |
| Dewatering, Diatomite filtration, Filter add, TN, TP, Water contents |
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