Jet Loop 反應器를 利用한 發水의 生物學的 窒素除去 硏究
(A) Study on the Biological Nitrogen Removal in the Wasterwater Using the Jet Loop Reactor
Jet Loop 폐수 질소제거 환경공학;
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본 硏究에서는 有機炭素가 거의 없으며 高濃度 窒素를 함유한 化學肥料廢水와 有機炭素와 窒素가 동시 함유된 皮革廢水를 Jet Loop 反應器를 이용하여 化學肥料廢水는 後段脫窒시스템(Post-denitrification system)으로 皮革廢水는 前段脫窒시스템(Pre-denitrification system)으로 현장 Pilot Plant를 설치하여 窒酸化 및 脫窒을 위한 最適 設計因子를 導出코자 하였으며 그 結論은 다음과 같다. 1. 化學肥料廢水 유입 평균 T-N농도 656mg/L이 HRT 3일 이상에서 유출농도 10mg/L이하로 98%이상 除去效率을 보였다. 窒酸化의 경우, 유입 TKN 475mg/L이 90%의 安定的 窒酸化를 위해 容積負荷率 0.5kgTKN/㎥·d이하, TKN 슬러지 負荷率 0.1kgTKN/kgVSS·d이하, SRT 8d이상이 요구되었고, 이때 比體積窒酸化速度는 최대 18mgTKN/L·h에 도달하였다. 脫窒의 경우, 20mg/L이하의 유출 NO_(3)-N농도와 95%이상을 脫窒率을 얻기 위하여 無酸素槽에 메탄올은 3kgCH_(3)OH/kgNO_(3)-N이 요구되며, NO_(3)-N容積負荷率은 0.7kg/m3·d이하, 슬러지 負荷率은 0.12kgNO_(3)-N /kgVSS·d이하로 運轉 되어야 하며, 슬러지 發生量은 최대 0.83kgTS/kgTN_(Re)로 예상되었으며, 이때 比脫窒速度는 각각 5.5mg NO_(3)-N/gVSS·h이었다.
This study was conducted to determine optimum design parameters in nitrification and denitrfication of chemical fertilizer wastewater and leather wastewater by using pilot plant, Jet Loop Reactor. Chemical fertilizer wastewater which contains low amounts of organic carbon and has a high nitrogen concentration requires a Post-denitrfication system, and leather wastewater requires a Pre-denitrfication system. The results are summarized as follows. In the case of chemical fertilizer wastewater, nitrogen removal efficiency was 98% or more at HRT over 3days, T-N average influent concentration 656mg/L was reduced to 10mg/L or less. In the operating condition of TKN volumetric loading 0.5kg TKN/m^(3)·d lower, TKN sludge loading 0.1kg TKN/kg VSS/d or less and more than SRT 8 days, nitrification efficiency was 90% or more. At this time, specific nitrification rates were at a maximum of 184.8mg TKN/L·hr. Methanol 3kgCH_(3)OH/kg NO_(3)-N, NO3-N volumetric loading 0.7kg NO3-N/m^(3)·d lower, NO_(3)-N sludge loading 0.12kg NO_(3)-N/kg VSS/d lower was required to obtain effluent NO_(30-N concentration levels of less than 20 mg/L. At this time, sludge production was maximum 0.83kgTS/kg T-N_(re), specific denitrfication rates were at 5.5 mgNO_(3)-N/g VSS·h. In the case of leather wastewater containing of BOD_(5), 512mg/L, COD 1,073mg/L, SS 198mg/L and T-N 262mg/L, removal efficiency of BOD_(5), COD, SS and T-N was more than 95%, 92%, 87% and 85%, respectively. To achieve more than 97% nitrification efficiency, optimum operating condition were founded to volumetric loading 0.6kg TKN/㎥·d or less, sludge loading 0.1kg TKN/kgVSS·d or less, SRT were more than 10d. In the case of denitrification, optimum NO_(3)-N volumetric loading for anoxic reactor was 0.75kg NO_(3)-N/㎥·d. At this time, specific denitrfication rates were at 1.8mgNO_(3)-N/g VSS·h. Operating cost included electric power, methanol dose and sludge disposal were 1,170won per T-N removed in chemical fertilizer wastewater and 870won leather wastewater, respectively. T-N removal process using Jet Loop Reactor was more economical than other processes without Jet Loop Reactor.