Applicability Evaluation of Fenton Oxidation Process for Livestock Carcasses Leachate Treatment

Abstract

ABSTRACT

Domestic animal infectious disease has become a serious problem in world wide. In 2010, there was a Foot-and-Mouth disease outbreaks in Korea. When animal infectious disease occurred, livestock carcasses were buried around farm to prevent the further infection. However, because of rapid spread of infection and leakage of livestock carcasses leachate which occurred from lack of disposal regulation, many environmental problems arisen. In general, pollutants concentration of livestock carcasses leachate were much higher than animal wastewater or ordinary sewage. Livestock carcasses leachate in burial site is treated by in-situ processes and then treated by nearby sewage treatment plant. In this research, Fenton oxidation process was applied to reduce the pollutants load of livestock carcasses leachate, before treated by sewage treatment plant and evaluated applicability. Fenton oxidation reaction was experimented for reducing of the organic matters in livestock carcasses leachate. 50-fold diluted livestock carcasses leachate was used and optimal conditions of this process were pH 3, 5 g/L of FeSO4, and 90 mL/L of H2O2. About 1,790 mg/L of CODCr was reduced in optimal condition. However, actual optimal dose of H2O2 was much higher than theoretical optimal. As a result of VFAs concentration analysis, comparatively high-molecular compounds were oxidized rapidly with in 10 minutes, and concentrations of low-molecular compounds (i.e., formic and acetic acids) were increased. Organic matters were need each H2O2 requirement during each oxidized step. This means H2O2 is needed for abundant organic matter condition. As a results of sterilization of E.coli, all of E.coli was sterilized through Fenton oxidation reaction. In addition to the Fenton oxidation process, to evaluate the applicability of the multi process system which includes coagulation /flocculation-sedimentation (CFS) process, granular activated carbon (GAC) adsorption, and zeolites adsorption, characteristics of each process was evaluated. CFS process is widely used for suspended solids and high-molecular compounds reducing, and GAC is effectively used for low-molecular compounds and color of the wastewater treatment. Natural zeolite was widely used as adsorbent for NH4-N adsorption, and Mg-modified zeolite can be use for simultaneous adsorbent for NH4-N and microorganism adsorption. Based on the previous research, CFS and GAC adsorption processes are suitable for organic mattes reducing and zeolites adsorption process is suitable for NH4-N reducing. Therefore the multi process system operate for the livestock carcasses leachate treatment, it can be treat more effectively.|국문 요지

가축 매몰지 침출수 처리를 위한 펜톤 산화 공정의 적용가능성 평가

정영철 건설환경공학과 대학원 한양대학교

가축 전염병은 전 세계적으로 많은 문제가 되고 있다. 한국에서도 2010에 구제역이 발병하였는데, 전염병의 확산을 방지하고자 폐사된 가축 사체는 농가 주변에 매몰하였다. 하지만 빠른 확산 속도와 처리 규정의 부제로부터 발생한 가축 매몰지 침출수는 많은 환경문제를 일으켰다. 일반적으로 가축 매몰지 침출수의 오염 농도는 가축 폐수나 일반 하수에 비해 그 농도가 매우 높다. 가축 매몰지 침출수는 매몰지 현장에서 1차적으로 현장 처리를 한 후, 인근 하수처리장으로 옮겨져 정화를 하는 방식으로 처리되고 있다. 본 연구에서는 하수 처리장의 연계처리 전에 가축 매몰지 침출수의 오염 부하를 줄이고자 펜톤 산화 공정을 적용하고 그 가능성을 평가하였다. 가축 매몰지 침출수 내의 유기물질 저감을 위해 펜톤 산화 반응을 실험하였다. 50배 희석시킨 침출수를 사용하였으며, 이를 대상으로 한 최적조건은 pH 3, FeSO4 5 g/L, H2O2 90 mL/L로 나타났다. 약 1,790 mg/L의 CODCr가 최적조건에서 저감되었다. 하지만 H2O2의 실제 최적 주입량은 이론적 최적 주입량에 비해 매우 많이 첨가되었다. VFAs 농도 분석 결과, 비교적 높은 분자량을 갖는 물질은 10분 이내에 빠르게 산화되었으며, 낮은 분자량을 갖는 물질(포름산, 아세트산)은 증가하는 것으로 나타났다. 유기물질이 산화되는 동안 각각의 단계에서는 각각의 H2O2가 필요한데, 이는 유기물이 많은 조건에서는 더 많은 H2O2가 필요하다는 것을 의미한다. 미생물 사멸 실험 결과, 펜톤 산화 공정을 통해 모든 대장균이 사멸된 것을 확인하였다. 펜톤 산화 공정 이외에 응집∙침전, 활성탄 흡착, 제올라이트 흡착 공정을 포함하는 복합공정의 적용 가능성을 평가하고자 각 공정의 특성에 대해 조사하였다. 응집∙침전 공정은 일반적으로 폐수 내의 부유물질이나 고분자 물질의 저감에 널리 사용되고, 입상 활성탄은 저분자 물질이나 색도 제거에 유용하게 사용된다. 천연 제올라이트는 암모니아성 질소의 흡착제로써 널리 사용되고, 마그네슘 치환 제올라이트는 암모니아성 질소와 미생물을 동시에 흡착할 수 있는 흡착제로 사용 가능하다. 위의 결론을 바탕으로 가축 매몰지 침출수 처리를 위해 복합 공정 시스템을 구축한다면 더 효과적으로 침출수 처리가 가능할 것이다.; ABSTRACT

Domestic animal infectious disease has become a serious problem in world wide. In 2010, there was a Foot-and-Mouth disease outbreaks in Korea. When animal infectious disease occurred, livestock carcasses were buried around farm to prevent the further infection. However, because of rapid spread of infection and leakage of livestock carcasses leachate which occurred from lack of disposal regulation, many environmental problems arisen. In general, pollutants concentration of livestock carcasses leachate were much higher than animal wastewater or ordinary sewage. Livestock carcasses leachate in burial site is treated by in-situ processes and then treated by nearby sewage treatment plant. In this research, Fenton oxidation process was applied to reduce the pollutants load of livestock carcasses leachate, before treated by sewage treatment plant and evaluated applicability. Fenton oxidation reaction was experimented for reducing of the organic matters in livestock carcasses leachate. 50-fold diluted livestock carcasses leachate was used and optimal conditions of this process were pH 3, 5 g/L of FeSO4, and 90 mL/L of H2O2. About 1,790 mg/L of CODCr was reduced in optimal condition. However, actual optimal dose of H2O2 was much higher than theoretical optimal. As a result of VFAs concentration analysis, comparatively high-molecular compounds were oxidized rapidly with in 10 minutes, and concentrations of low-molecular compounds (i.e., formic and acetic acids) were increased. Organic matters were need each H2O2 requirement during each oxidized step. This means H2O2 is needed for abundant organic matter condition. As a results of sterilization of E.coli, all of E.coli was sterilized through Fenton oxidation reaction. In addition to the Fenton oxidation process, to evaluate the applicability of the multi process system which includes coagulation /flocculation-sedimentation (CFS) process, granular activated carbon (GAC) adsorption, and zeolites adsorption, characteristics of each process was evaluated. CFS process is widely used for suspended solids and high-molecular compounds reducing, and GAC is effectively used for low-molecular compounds and color of the wastewater treatment. Natural zeolite was widely used as adsorbent for NH4-N adsorption, and Mg-modified zeolite can be use for simultaneous adsorbent for NH4-N and microorganism adsorption. Based on the previous research, CFS and GAC adsorption processes are suitable for organic mattes reducing and zeolites adsorption process is suitable for NH4-N reducing. Therefore the multi process system operate for the livestock carcasses leachate treatment, it can be treat more effectively.