• 한국물환경학회지
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• 제22권1호
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• pp.91-96
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• 2006

Many small scale Sewage Treatment Plants (STPs) are currently being constructed at many rural areas. The STPs in rural area suffer from low concentration and large inflow quantity fluctuation during wet weather mainly due to illicit combined sewer system. Sequencing Batch Reactor (SBR) is a process effectively coping with these obstacles. The main objective of this study was to evaluate SBR with high hydraulic loading and low inflow concentration. The operating conditions tested were: organic loading rate = $0.17-0.42KgBOD/m^3/d$, hydraulic loadings = $12.1-61.5m^3/m^2/d$, average MLSS concentration = 2500 mg/L, F/M ratio = 0.026-0.17 KgBOD/Kg MLSS, HRT = 9-12 hr HRT, and SRT = 5.6-33.6 days. Organic loading rate on SBR did not impact significantly on BOD and SS removal efficiencies. To increase treatment efficiencies, low hydraulic loading rate with low concentration was required. The results suggested that low influent concentration with high inflow rates during wet weather requires extended time for settling.

• 환경위생공학
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• 제14권2호
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• pp.25-31
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• 1999

Energy recovery technology from municipal solid waste has been increasingly established in many countries. Anaerobic treatment of municipal sewage sludge has low digestion efficiency because of low organic loading rate of sewage sludge. The purpose of this study was to evaluate anaerobic biodegradability of food waste which was based on organic loading rate and seeding rate. From the results of anaerbic biodegration, the optimum condition for seeding rate was turn out over 40%, which did not inhibition of methane production.

• 한국환경과학회지
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• 제13권9호
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• pp.779-878
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• 2004

This study was conducted to analyze the operating conditions of predenitrification process to improve the treatment efficiency in low organic loading sewage plant in use today, and to investigate the treatment efficiency of pilot plant added night soil as well as the nitrogen removal characteristics of pilot plant added carbon sources. In the operation under the condition of $BOD_{5}$ sludge load 0.03-0.28kg $BOD_{5}$/kg VSS/d and oxic ammoniac nitrogen sludge load 0.02-0.24 $kgNH_{4}^{+}$-N/kg MLVSS/d, nitrification efficiency is higher than 95%. In order to achieve 70% nitrogen removal at the T-N sludge loading 0.06kg T-N/kg VSSㆍd and the SRT 6～11 days, optimum operating factors were revealed to $CODc_{r}$/T-N ratio 9, recycle ratio 2.6, and denitrification volume ratio 0.33. At this time, denitrification capacity was approximately 0.09 kg $NO_{3}^{-}$-N/kg $CODc_{r}$; specific nitrification rate was 3.4mg $NH_{4}^{+}$-N/g MLVSS/hr; and specific denitrification rate was 4.8mg $NO_{3}^{-}$-N/g MLVSS/hr.

• 상하수도학회지
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• 제11권1호
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• pp.64-73
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• 1997

Most of the municipal wastewater treatment plants operated in Korea are designed for high concentrations municipal sewage. However, activated sludge process employed by municipal wastewater treatment plant is operated at low organic loading. The objective of this study was to determine optimum operating condition of activated sludge process for treatment of low concentration municipal sewage. Three bench scale activated sludge reactors were operated to investigate the effect of HRT and SRT on the COD and TSS removal efficiency. The average concentration of TSS, SCOD, SBOD and TKN in influent were 118mg/l, 61mg/l, 21mg/l, and 12mg/l, respectively. The activated sludge reactors operated with various HRT and SRT showed about 89-93% TSS removal efficiency. HRT and SRT does not affect the TSS removal efficiency of actvatied sludge process significantly. However, HRT affected the SCOD removal efficiency slightly. As the HRT decreases from 13hours to 3hours, the SCOD removal efficiency decreases from 67% to 56%. The average effluent TCOD concentration of the reactor operated with 3hours of HRT was approximatly 40-45mg/l. Kinetic coefficient yield (Yt) and decay coefficients(Kd) were 0.594-0.954 mgMLVSS/mgCOD and $0.0197-0.0317day^{-1}$, respectively. Low concentration municipal sewage can be treated with 3 hours of HRT without effluent quality deterioration and SRT does not affect the substrate removal efficiency at this operation condition.

• 한국환경농학회지
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• 제27권1호
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• pp.27-34
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• 2008

농어촌 등에서 소규모로 발생하는 하수를 자연정화공법 의한 인공습지에서 효과적으로 처리하기 위하여 소형 하수처리장치를 호기성조 및 혐기성조로 구분하여 시공한 다음, 최적 하수 부하량을 조사하기 위해 하수 부하량별 오염물질의 처리효율을 조사한 결과 호기-혐기 조합형 소형 하수처리장에서 전반적으로 하수 부하량이 증가함에 따라 오염물질의 처리효율이 점점 감소하는 경향으로 특히 하수부하량 300 $Lm^{-2}day^{-1}$ 이상에서 수처리효율의 감소폭이 약간 컸다. 따라서 본 소형 하수처리장에서 BOD, $COD_{Mn}$, 탁도, T-N 및 T-P를 안정적으로 처리하기 위한 최적 부하량은 300 $Lm^{-2}day^{-1}$ 이었고, 이 때의 방류수 중 BOD, $COD_{Mn}$, 탁도, T-N 및 T-P의 처리효율은 각각 99, 94, 99, 49 및 89%로 현행 방류수 수질기준을 만족하면서 안정적으로 처리되었다. 하지만 본 소형 하수처리장에서 방류수 중의 T-N 및 T-P 함량은 각각 $28.5{\sim}29.4$ 및 $0.9{\sim}2.1mgL^{-1}$ 정도로서 앞으로 질소와 인의 방류수 수질기준이 각각 20 및 2 $mgL^{-1}$로 강화됨에 따라 보다 안정적인 수처리를 위해서는 T-N 및 T-P 처리효율을 향상시켜야 할 것으로 판단된다. 이에 최적 하수 부하량하에서 질소와 인의 강화될 방류수 수질기준(질소 20 $mgL^{-1}$ 및 인 2 $mgL^{-1}$)을 만족시키면서 안정적인 하수처리를 위한 최적의 수처리 공정개선 방안을 조사하였다. 호기-혐기 조합형 소형 하수처리장에서 수처리 공정개선 중 질소 및 인의 처리효율 향상이 가능한 방안은 혐기성조의 깊이 및 여재 입경 변경과 여재에 굴패각을 혼합한 방법이었다. 혐기성조의 깊이 및 여재 입경 변경 조건 중 혐기성조 1.5 m 깊이에서 여재 A(유효입경 1.50 mm)를 사용한 경우 T-N 및 T-P의 처리효율을 각각 10 및 3% 향상시켰고, 여재에 굴패각 혼합한 경우 T-N 및 T-P의 처리효율을 각각 14 및 7% 향상시켰다. 또한 동일한 조의 체적하에서 혐기성조의 깊이를1.5 m로 깊게한 것은 혐기성조 깊이 1 m에 비해 부지면적을 약 33% 정도 감소시킬 수 있을 것으로 판단되며, 또한 굴패각을 사용한 것은 폐기물의 재활용면에서도 매우 효과적인 방안으로 사용될 수 있을 것으로 판단된다.

• 상하수도학회지
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• 제19권6호
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• pp.749-757
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• 2005

The present study analyzed actual cases of designed flow estimation method and designed flow rate of sewage pipe lines. In order to examine the effects of peak-hour demand factor estimation with given daily highest peak loading, we analyzed its effects on designed flow rate with changing the peak-hour demand factor from 2.0 to 10.0. The results of this study are as follows. When reviewing the recent designs, we found that 59.4% of pipe line with 250mm and 300mm diameter, which fall under minimum allowable pipeline did not meet the minimum velocity which is specified as 0.6m/sec in design standards. The pipe line that have minimal access population or have very low slope did not satisfy the minimum velocity. In estimating the designed sewage flow, the applied daily highest peak loading and hourly highest peaking loading were the load factor for the entire population of the planned area, and for the peak loading of the initial pipes connected to a very small population, we applied the same factor as that applied to the entire area and, as a result, the hourly highest flow was underestimated. Because, in case of the initial pipes, the method of applying the same peak loading to all subject areas is highly possible to produce underestimated design flow, when estimating the designed flow of the initial pipes connected to a small population need to adopt a rational flow factor according to the size of population. For this, it is considered to investigate and analyze raw data on daily and hourly variation of sewage flow.

• 대한환경공학회지
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• 제34권9호
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• pp.583-589
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• 2012

하수슬러지의 처분 방안으로서 하수슬러지를 생활폐기물과 혼합소각시의 가능성을 타진하기 위해 전체폐기물 중 하수슬러지를 20%까지 혼합하여 실험한 결과, 열부하 및 대기오염물질(질소산화물, 황산화물)부하에 영향을 크게 주지 않는 것으로 나타났다. 생하수슬러지(함수율 78.8%) 및 건조하수슬러지(함수율 60%)를 혼합소각한 결과, 건조하수슬러지를 혼합한 경우에는 열부하변동이 거의 없었으나 생하수슬러지를 혼합소각한 경우는 열부하가 다소 낮아지는 것으로 나타나 전처리를 한슬러지 혼합소각이 평상시와 같은 운전조건으로 소각로 연소를 이룰 수 있을 것으로 판단되나 고발열 생활폐기물 발열에 의한 소각로 파손을 방지하기 위해서는 에너지 비용 및 슬러지 경화현상에 의한 국부소각 방지 등을 고려하여 생하수슬러지에 수분을 공급하여 소각하는 방안도 고려해 볼만 하다고 판단된다.

• 한국환경농학회지
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• 제2권2호
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• pp.90-97
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• 1983

진주시내(晋州市內) 생활하수(生活下水)의 수질실태(水質實態)를 파악(把握)하여 그것이 남강(南江) 수질오염(水質汚染)에 미치는 영향을 검토(檢討)함으로써 남강(南江) 수질보전대책(水質保全對策) 수립(樹立)에 대(對)한 삼고자료(參考資料)를 제공(提供)코자 진주시내(晋州市內) 생활하수(生活下水)의 주요(主要) 5개(個) 배출구역(排出區域)과 진양호(晋陽湖) 및 남강(南江) 각(各) 1 개(個) 지점(地點)의 수질(水質)을 분석(分析)하였다. 1) 진주시(晋州市) 5개(個) 하수구역(下水區域) 배출수질(排出水質)의 각(各) 성분(成分) 평균치(平均値)는 pH 7.1, DO 2.3 ppm, BOD 126.2ppm, COD 123.7ppm, 탁도(濁度) 22.3ppm, $NH_4^+-N 9.3 ppm$, 알카리도 121ppm 경도(硬度) 121ppm, Cl- 44.3ppm, $SO_4--$ 88.9 ppm, Pb 0.0052 ppm, Zn 0.0079 ppm, Cu 0.0124ppm, Mn 0.0050 ppm 이었다. 2) 남강(南江)의 1일(日) 총(總) BOD 부하량(負荷量)은 14.80 ton이었으며 이 중 남강상류(南江上流)인 진양호(晋陽湖)로부터 6.94Ton, 그리고 진주시(晋州市) 下水(下水)로부터 4.93 ton이 류입(流入)되고 있었다. 따라서 하수(下水)가 차지하는 BOD 부하량(負荷量)은 33.3%였다. 3) 하수중(下水中)의 중김속함량(重金屬含量)은 낮아 남강(南江) 수질오염(水質汚染)에 그리 큰 영향을 미치지 않을 것이나 암모니아태(態) 질소(窒素)가 대단히 높아 농업(農業) 용수(用水)로 이용(利用)하기에는 불적당(不適當)할 것이로 사료(思料)된다. 4) 남강수질(南江水質)의 오염도(汚染度)를 농업용수기준치인 BOD 8ppm 이하(以下)로 줄이기 위해서는 진양호(晋陽湖) 남강(南江)댐에서의 방류량(放流量)을 $1,900,000 ^3$/일(日) 이상(以上)으로 조절해야 할 것으로 본다.

• 한국환경농학회지
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• 제19권5호
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• pp.426-432
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• 2000

Field experiment was performed from August 1996 to December 1999 to examine the feasibility of constructed wetland system for sewage treatment in rural areas. A pilot system was installed in Konkuk University and the effluent of septic tank for school building was used as an influent to the wetland treatment basin. The system was composed of sand and reed, and operated continuously including winter time. Average removal rate of about 70% was observed for BOD, COD, and SS, about 50% for T-P, and about 25% for T-N. The reason for poor T-N removal might be due to high loading rate and short retention time. The system demonstrated satisfactory effluent concentration and stable performance in growing season. And it also worked adequately in wintertime even below $10^{\circ}C$ without freezing, and removal was still significant. The amount removed in BOD, COD, and SS was almost the same as in the growing season, and the amount removed in nutrients was about half of the one in growing season. Overall performance of the experimental system was compared with existing data base (NADB, 1994), and it was within the range of general system performance. As study period increased, removal rates for BOD, COD, SS, and T-P were consistently maintained and even enhanced, but removal rate for T-N decreased slightly. Wetland system was thought to be a feasible alternative for sewage treatment in rural area considering its low cost and low maintenance requirement. However, the effluent of the experimental wetland system often exceeded current effluent water quality standards, therefore, further treatment could be required if the effluent should be discharged to public waters. Wetland system of interest locates in rural area and is a part of rural ecosystem, therefore, ultimate disposal of reclaimed sewage for agricultural purpose or subsequent land treatment might be available and further research in this matter is recommended.

• 한국환경과학회지
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• 제15권11호
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• pp.1017-1025
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• 2006

This study was conducted to evaluate characteristic of water duality in coastal sea of Incheon using a multivariate analysis. The analysis data in coastal sea of Incheon was aquired by the NFRDI data which was surveyed from March 1997 to November 2003. Eleven water quality parameters were determined on each survey The results were summarized as follow : Water quality in Incheon coastal sea could be explained up to 64.62% by three factors which were included in loading of fresh water and nutrients by the land(36.98%), seasonal variation(16.19%), and internal metabolism (11.24%). The results of time series analysis by factor score, in case of factor 1, station 1 influenced by Han river was shown to high factor score and station 3 located by outer sea was shown to low factor score. In case of factor 2, station 1 was appeared to high variation and station 3 was appeared to low variation. The result of cluster analysis by station was classified into three group that has different water quality characteristics. Especially, station 1 which affected by Han river and station 4 which affected by sewage treatment plant was appeared to considerable water quality characteristics against other station. In yearly cluster analysis, three group was classified and water quality in 2003 years due to high precipitation was different to another year. It could be suggested from these results that it is important to control discharge of fresh water by Han rivet and sewage treatment plant for water quality management of coastal sea of Incheon.