Biological Nitrification and Denitrification for Landfill Leachate Containing High Concentration of Ammonium-Nitrogen by using MLE Process

MLE 공정을 이용한 고농도 NH₄⁺-N 함유 침출수의 생물학적 질산화/탈질

This study was carried out to investigate the treatability of landfill leachate having high concentration of ammonium nitrogen with/without the circulation of media in pilot-scale($48m^3basis$) process. Total nitrogen removal efficiency was relatively increased in the media added process (influent ; $1.230{\sim}2,000mg{\cdot}l^{-1}$, effluent ; $120{\sim}250mg{\cdot}l^{-1}$) compared with the control process. The difference of nitrogen removal efficiency between these processes may be due to that stable growth of nitrifiers attached to the media could be achieved 99.3% of ammonium-nitrogen removal efficiency(without ; 98.2%) and 88.5% of total nitrogen removal efficiency(without ; 85.8%) were shown in media added process, respectively. Also, optimum BOD/ $NH_4{^+}$-N ratio was relatively decreased in the media process compared with the control process. Sludge settleability, on the other hand. was shown better in media added process than in control process. This outstanding sludge settleability in the media added process indicates the compatibility of media(zeolite) to the microorganism and the possibility of using media of biofilm process.

본 연구에서는 생활폐기물 매립지에서 발생되는 침출수에 함유된 고농도 $NH_4{^+}$-N 및 T-N의 적정처리를 위하여 pilot 규모의 MLE 공정을 이용하여 생물학적 질산화/탈질을 실시한 결과 $NH_4{^+}$-N온 99%이상, T-N은 88%정도의 처리효율을 얻을 수 있었으며, BOD/$NH_4{^+}$-N비를 약 3.5로 유지할 경우 T-N온 $0.09kgN{\cdot}m^{-3}{\cdot}day^{-l}$정도 제거되는 것으로 나타났다. 또한, 질산화/탈질과정에서 $NH_4{^+}$-N 산화량에 따른 알카리도 소비량은 평균 $3.4{\sim}3.5kgAlk{\cdot}kgNH_4{^+}-N^{-1}$정도로 나타났으며, 외부탄소원으로 투입된 메탄올에 대한 탈질균의 적용 기간은 약 20일 정도가 필요한 것으로 나타났다. 또한, 질산화조에 유동상 메디아를 투입한 결과 투입하지 않았을 때에 비하여 $SV_{30}$가 2배 정도 양호하게 나타났다.