전해충진탑을 이용한 하수슬러지 건조가스 중 악취 및 VOCs 저감 특성

Abstract

Recently, most of organic sewage sludge depends on ocean dumping due to government's prohibition of direct dumping and landfill. But ocean discharge will be prohibited in the near future based on London Dumping Convention/protocol. Therefore, the government is considering the policy of sewage sludge to substitute the ocean dumping. The sewage sludge is high moisture content, so it can be a reason of inefficient incineration. Drying is very important process in the sewage sludge treatment and the recycling process. However, odor and volatile organic compounds are emitted from the sludge drying process. The odor was the reason of the discontent about the sewage sludge treatment plants. In this study, it used packed-bed which is filled with zeolite media and it can expand specific surface area and electrolysis water for removing odor and volatile organic compounds. Electrolysis water (acid and alkali) was produced by electrolysis technology. The experimental device is setup consists of alkali packed-bed, acid packed-bed, flow meter, pump and a bag of mixed gas. Mixture of gases made of standard gases: acetaldehyde, propionaldehyde, valeraldehyde, isovaleraldehyde, butyraldehyde, isobutyraldehyde, hydrogen sulfide, methylmercaptan, dimethyl sulfide and dimethyl disulfide. This study used polyester aluminum sampling bag and Teflon tube. Device driving condition is as the following; gas flow rate: 0.4 L/min, the ratio of liquid and gas: 4 L/m3. The empty bed retention time is 10 min. An absorbent is used by NaOH solution, NaOCl solution and electrolysis water. The findings from this study are as follows; - When using a NaOCl solution, the sulfur compounds removal efficiency was higher than NaOH solution. - The electrolysis water showed more efficiency than the chemicals' to remove odor and VOCs. - Dual system which combines acid and alkali is more effective than packed tower which is packed only one item (acid or alkali) for odor and VOCs treatment.