Nutrient removal in reverse osmosis concentrates using a biological aerated filter

IWA PUBLISHING 2015 WATER SCIENCE AND TECHNOLOGY -WATER SUPPLY- Vol.15 No.2

<P>The aim of this study is to employ a biological aerated filter (BAF) in the treatment of reverse osmosis (RO) concentrate received from reuse of treatment plant wastewater. Furthermore, the influence of chemical oxygen demand (COD)/N ratio on the nutrient removal was analyzed to find the detailed removal pathways of nutrients. The result was found to be high efficiency for biochemical oxygen demand removal (95.86%) compared to that of COD (88.95%) and suspended solids (81.12%). The total phosphorus (TP) (67.66%) and PO<SUB>4</SUB>-P (61.42%) removal efficiencies were relatively lower than that of total nitrogen (TN) (81.42%) and NO<SUB>3</SUB>-N (76.70%). This may be due to the fact that the biochemical oxygen demand (BOD)/TP ratio (8.01) was relatively low. Decreasing the COD/N ratio decreased TP and PO<SUB>4</SUB>-P removal efficiency. However, the removal efficiency of TN and NH<SUB>4</SUB>-N was increased from 47.60 to 64.54 and 54.17 to 73.72% with decreasing of COD/N ratio from 8.19 to 7.64, respectively. In addition, the denitrification rate and nitrification rate were increased from 211.8 to 301.0 mg/L d and 87.7 to 109.4 mg/L d, respectively, when COD/N ratios changed from 8.19 to 7.64. Therefore, in order to reuse the RO concentrate, the BAF process could effectively treat the RO concentrate.</P>

혼합 산업폐수의 질소제거를 위한 외부 탄소원 투입과 물질수지: 실증실험

이몽학 ( Mong Hak Lee ),안조환 ( Jo Hwan Ahn ),이정훈 ( Jung Hun Lee ),배우근 ( Woo Keun Bae ),심호재 ( Ho Jae Shim ) 한국물환경학회 2012 한국물환경학회지 Vol.28 No.5

The feasibility of enhancing biological nutrient removal from an industrial wastewater was tested with food waste leachate and sugar liquid waste as external carbon sources. Long term influences of adding external carbon sources were investigated to see how the biological nutrient removal process worked in terms of the removal efficiency. The addition of the external carbons led to a significant improvement in the removal efficiency of nutrients: from 49% to approximately 76% for nitrogen and from 64% to around 80% for phosphorus. Approximately, 20% of the removal nitrogen was synthesized into biomass, while the remaining 80% was denitrified. Though the addition of external carbon sources improved nutrient removal, it also increased the waste sludge production substantially. The optimal observed BOD/TN ratio, based on nitrogen removal and sludge production, was around 4.0 in this study.

회전원판공정과 화학침전공정 조합을 이용한 유기물과 질소*인의 동시제거

박종안,허준무,손부순 한국환경보건학회 1998 한국환경보건학회지 Vol.24 No.1

회전원판공정(rotating biological contactorRBC)과 화학적 처리공정을 결합한 처리시스템을 이용하여 도시하수내 포함된 유기물과 영양염류를 제거할 경우에 수리학적 부하 (hydraulic loading)와 처리수 반송율 (recirculation rate)의 시스템 처리효율에 미치는 영향을 알아보고자 하였다. 각각의 수리학적 부하 0.031, 0.0535 및 0.076 $m^3/m^2/d에서 반송율을 100%, 200%, 300%로 변화시켰고, 질산화에 필요한 알카리도의 보충 및 화학적 처리를 위하여 lime(CaCO$_3$)을 가하여 유입수의 pH를 10.4-11.0으로 유지시켰다. 실험결과 수리학적 부하 0.0535 $m^3/m^2/d에서 BOD, COD의 제거효율이 가장 높게 나타났으며, 질산화 효율 및 질소 제거효율에서는 수리학작 부하 0.035 $m^3/m^2/d, 반송율 300%에서 가장 높았으며, 반송율별에서는 수리학적 부하를 고려할 때 300% 반송하는 것이 가장 높은 유기물 제거효율을 보였다. 반송율과 수리학적 부하를 증가시킬 경우에 발생되는 슬러지내 유기물 함량은 점점 증가하였고, 수리학적 부하 0.076 $m^3/m^2/d, 반송율 300%일 경우에는 유기물 함량이 47%로 매우 높았다. 이는 부하증가에 따른 미생물 성장의 증가와 더불어 수리학적 부하 증가에 따른 전단력의 증가가 영향을 미쳤기 때문이다. 인을 제거하기 위하여 pH를 10.4-11.0으로 유지시킨 경우에 인을 90%이상 제거할 수 있었으며, 유출수내 평균 SS농도는 40 mg/l를 상회하였다. Laboratory-scale experiments were conducted using a three-stage rotating biological contactor unit followed by lime precipitation and sedimentation with effluent recycle to the first stage. The purpose of this study was to evaluate the effects of hydraulic loadings of 0.031-0.076 $m^3/m^2/d and recycle ratio of 1 to 3 on the simultaneous removal of organics and nutrients from domestic wastewater. Lime was added to maintain pH of 10.4-11.0 in the coagulation-flocculation reactor. Results showed that the highest nitrogen removal rate of 70.5% occurred at the lower hydraulic loading of 0.031 $m^3/m^2/d at a recirculation rate of 300%, and similarly, highest nitrification occurred at the same hydraulic loading and recycle ratio. Concentration of ammonia nitrogen in the effluent was less than 1 mg/l at the same operating conditions for higher nitrogen removal. Whereas, high BOD and COD removal was observed at hydraulic loading rate of 0.054 $m^3/m^2/d, and high removal of organic matter was evident from the consistent low COD and BOD value. Results obtained from the operating condition of higher loading rate, 300% of recycle rate showed the highest removals. Increasing in recycle rate and hydraulic loading rate increased the volatile solids fraction of the sludges generated to the extent of 47% at 0.076 $m^3/m^2/d hydraulic loading and 300% recirculation rate. Since pH in the flocculator was maintained at the pH of 10.4-11.0, above 90% removal of phosphorus was obtained. Average concentration of suspended solids was always maintained over 40 mg/l in the effluent. Therefore an RBC unit operating at a hydraulic loading near 0.031 $m^3/m^2/d with a recycle rate of 300% is a viable and feasible alternate conditions to produce an effluent with relative low organic matter and phosphorus, provided that there is a neutralization unit to control the pH and SS of the effluent.

A Systematic Process Optimization Method for Advanced Environmental Process

Min Han Kim,Chang Kyoo Yoo 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10

A systematic approach is proposed to find optimal operational conditions for nitrogen and phosphorus (N, P) removal in a biological nutrient removal processes, which is the dual optimization strategy through modeling, variable selection, design of experiments, and optimization using multiple response surface methodology. It is focused on determining the interactive effects between independent variables for N and P removal, which are selected through a new sensitivity analysis for considering the effluent quality index. After selecting key operational variables, multi-response surface model based on a new desirability function is used for the dual optimization of N and P removal. Because the proposed method is a multi-response model which is the suitable methods to optimize the operational conditions in a process, it can simultaneously optimize the biological process in the aspect of N and P removal efficiency. The proposed method is applied to a standard A2O process. The model-based optimization results in 78.0% and 80.0% removal efficiencies of N and P removal with the optimal process conditions, where are internal recycle flowrate of 3,850 g/m3, dissolved oxygen (DO) concentration of 1.0 mg/l, and wasted sludge rate of 27.5 g/m<SUP>3</SUP>, respectively. The dual optimization suggests to maximize simultaneous nitrification and denitrification (SND) in A2O system. This study confirms that the proposed dual optimization method is useful to systematically optimize the N and P removal in any biological nutrient removal process.

(AO)2 SBBR과 A2O SBBR에서 영양염류 제거 특성 비교

박영식 ( Young Seek Park ),김동석 ( Dong Seog Kim ) 한국물환경학회 2006 한국물환경학회지 Vol.22 No.3

This study was carried out to compare the performance of two types of sequencing batch biofilm reactors (SBBRs), anoxic-oxic-anoxic-oxic (AO)2 SBBR and anoxic-oxic-anoxic A2O SBBR, on the biological nutrient removal. The TOC removal efficiency in A2O SBBR was higher than that in (AO)2 SBBR. At the 1st non-aeration period, the release of PO4(3-)-P in A2O SBBR was higher than that in (AO)2 SBBR because of the high TOC removal. At the 1st aeration-period, the nitrification was not completed in (AO)2 SBBR, however, it was completed in A2O SBBR and the nitrification rate in A2O SBBR was higher than that in (AO)2 SBBR. The release and uptake of PO4(3-)-P in A2O SBBR was much higher than in (AO)2 SBBR. Also, the profiles of DO and pH in reactors were used to monitor the biological nutrient removal in two SBBRs. The break point in DO and pH curves at the aeration period coincided with the end of nitrification.

(AO)₂ SBBR과 A₂O SBBR에서 영양염류 제거 특성 비교

박영식,김동석,Park, Young-Seek,Kim, Dong-Seog 한국물환경학회 2006 한국물환경학회지 Vol.22 No.3

This study was carried out to compare the performance of two types of sequencing batch biofilm reactors (SBBRs), anoxic-oxic-anoxic-oxic $(AO)_2$ SBBR and anoxic-oxic-anoxic $A_2O$ SBBR, on the biological nutrient removal. The TOC removal efficiency in $A_2O$ SBBR was higher than that in $(AO)_2$ SBBR. At the 1st non-aeration period, the release of ${PO_4}^{3-}-P$ in $A_2O$ SBBR was higher than that in $(AO)_2$ SBBR because of the high TOC removal. At the 1st aeration-period, the nitrification was not completed in $(AO)_2$ SBBR, however, it was completed in $A_2O$ SBBR and the nitrification rate in $A_2O$ SBBR was higher than that in $(AO)_2$ SBBR. The release and uptake of ${PO_4}^{3-}-P$ in $A_2O$ SBBR was much higher than in $(AO)_2$ SBBR. Also, the profiles of DO and pH in reactors were used to monitor the biological nutrient removal in two SBBRs. The break point in DO and pH curves at the aeration period coincided with the end of nitrification.

Biological nutrient removal with volatile fatty acids from food wastes in sequencing batch reactor

Ho-Nam Chang,Seong-Jin Lim,Eun-Young Kim,Yeong-Hee Ahn 한국화학공학회 2008 Korean Journal of Chemical Engineering Vol.25 No.1

Volatile fatty acids (VFAs) derived from food waste were used as an alternative carbon source in biological nutrient removal. The pH Profiles were monitored during the nutrient removal in an Na-acetate fed sequencing batch reactor (SBR) (C source). Effluent N, P and SCOD concentrations of 0.5 and 0.1 mg/L were achieved with 5.5 hour of HRT (hydraulic retention time) when influent concentrations of NH4+-N, PO43− and SCOD were 42.5, 5.92 and 180 mg/L. Then the SBR was fed with four solutions of VFAs produced under different acidogenesis conditions of food wastes. VFAs-added SBR showed similar specific nitrification rates (3.0 to 3.9 mg-N/g MLSS·h) to that of acetate, but specific denitrification rates (3.2 to 4.2 mg NO3 −-N/g MLSS·h) were slightly lower than with acetate of 4.67 mg NO3 −-N/g MLSS·h. VFAs-introduced SBR efficiently removed phosphorus except when the SBR was fed with a VFAsolution containing high amounts of valerate and caproate.

연속 회분식 반응기와 연속 회분식 생물막 반응기의 유기물, 질소 및 인의 동시 제거에 관한 비교 연구

박영식,김동석,Park Young-Seek,Kim Dong-Seog 한국환경보건학회 2005 한국환경보건학회지 Vol.31 No.2

Laboratory scale experiments were conducted to study the applicability, and to compare the performance of two types of sequencing batch reactor (SBR)systems, a conventional SBR and sequencing batch biofilm reactor (SBBR) on the biological nitrogen and phosphorus removal. The nitrification rate in SaR was higher than that in SBBR both in high influent TOC concentration. The denitrification was completed at the first non-aeration period in SBR, however, the additional non-aeration period should be installed or the first aeration period should be extended more in order to complete the nitrogen removal in SBBR. The time at the first aeration period was more needed as about 4-5 h in order to uptake all the released $PO_4^{3-}\;-P$ at the first non-aeration period. SBBR needed more operation time, especially the first aeration time, than SBR at the high influent TOC concentration in order to complete nitrogen and phosphorus removal.

(AO)$_2,$ SBR과 $A_2O$ SBR의 유기물, 질소 및 인의 제거에 관한 연구

박영식,우형택,김동석,Park Young-Seek,Woo Hyung-Taek,Kim Dong-Seog 한국환경보건학회 2005 한국환경보건학회지 Vol.31 No.4

Laboratory scale experiments were conducted to compare the performance of two types of sequencing batch reactor(SBR) systems, anoxic-oxic-anoxic-oxic $((AO)_2)$ SBR and anoxic-oxic-anoxic $(A_2O)$ SBR on the biological nitrogen and phosphorus removal. Also, the profiles of DO and pH in reactors were used to monitor the biological nutrient removal in two SBRs. The break point in the pH and DO curves at the oxic period coincided with the end of nitrifying activity at about 1 h 30 min in oxic phase, and the change in pH appears to be related to nitrate concentration. The TOC removal efficiency in $A_2O$ SBR was higher than that in $(AO)_2$ SBR. The denitrification was completed at the influent period. The 2nd non-aeration and aeration periods were not necessary for the nitrogen and phosphorus removal because of the low influent TOC concentration in this study. The release and uptake of phosphorus in $AO_2$ SBR was much higher than that in $(AO)_2SBR.$ In order to uptake more phosphorus, the 1st aeration period in $A_2O$ SBR should be prolonged.

2단 간헐 포기조의 포기/비포기 시간비에 따른 영양염류 제거특성

김홍태,신석우,오상화,권성현 한국환경과학회 2004 한국환경과학회지 Vol.13 No.7

This study was conducted to remove organics and nutrients using 2 stage intermittent aeration reactor. First reactor, using suspended microbial growth in intermittent aeration instead of anaerobic reactor in the typical BNR process, used minimum carbon source to release P. and it was possible to reduce ammonia loading going to second reactor. In the second reactor, using moving media intermittent aeration, it was effective to reduce nitrate in non-aeration time by attached microorganisms having long retention time. In aeration time, nitrification and P uptake were taken place simultaneously. From the experiment, two major results were as follows. First, the removal of organics was more than 90%, and optimum aeration/non-aeration time ratio for organic removal was corresponded with aeration/non-aeration time ratio for nitrogen removal. Second, in the first reactor, optimum aeration/non-aeration time ratio was 15/75 (min.) because it was necessary to maintain 75 min. of non-aeration time to suppress of impediment of return nitrate and to lead release of phosphate. In the second reactor, optimum aeration/non-aeration time ratio was 45/90 (min.).