• 대한환경공학회지
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• 제34권5호
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• pp.312-315
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• 2012

본 연구는 Media공법을 적용하고 있는 하수처리장의 실데이터를 활용하여 다중회귀분석을 통해 유출수질을 예측하는 모형을 구현하였다. 다중회귀분석은 2011년 1년간 데이터를 사용하였으며, 변수선택법 적용, 이상치와 영향치 제거, 변수의 로그변환에 따른 CASE별 연구를 수행하였다. 다중회귀분석으로 구축된 예측 모형으로 예측정확도를 검토한 결과, 2차침전지 유출수 $COD_{Mn}$는 0.87 이상, T-N은 0.81 이상으로 검토되었으며, 구축된 다중회귀모형을 이용하여 유출수가 방류수질기준을 초과하지 않는 운전조건의 범위를 설정할 수 있을 것으로 판단된다. 결론적으로 설정된 운전조건 범위 안에서 수질측면과 에너지 비용측면으로 하수처리장 운영시 운전자에게 적절한 운전 가이드를 제공할 수 있을 것으로 판단된다.

• 한국수자원학회논문집
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• 제35권2호
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• pp.213-220
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• 2002

하수 처리수의 재이용을 위하여 표준활성슬러지법에 의한 생물학적 처리 후 최종침전지 유출수를 급속여과공정으로 처리하기 위한 Pilot Plant 실험연구가 수행되었다. 또한, 활성슬러지와 연계된 급속여과공정과 포기조 후단에 응집제를 주입하는 활성슬러지 이후 급속여과 처리하는 공정과의 비교 실험도 행해졌다. 최종침전지 유출수를 급속여과공정으로 처리한 경우 여과속도는 100m/day, 여과지속시간은 40시간 이하로 운전하는 것이 타당한 것으로 나타났으며, 여과지의 역세척 주기는 여과속도 100m/day일 때 40시간에 1회 정도가 되었다. 여과지 역세척 시 역세척 방법은 공세 1분, 공세+수세 30초, 수세 1분, 공세·수세 2분, 수세 3분, 안정 30초, 배수 10분의 순으로 행하는 것이 효과적이었으며, 수세속도는 10LPM으로 전체 여과수량의 2%정도였다. 표준활성슬러지 시스템에 의한 2차 처리수를 잡용수로 재이용 하기 위해서는 폭기조 후단에 응집제를 첨가하여 여과 공정을 후속공정으로 하는 시스템으로 유용하게 사용할 수 있을 것으로 판단된다.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2003년도 학술발표논문집
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• pp.583-586
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• 2003

The objective of this research was to examine the significance of change to indicator microorganisms (TC, FC, and E. coli) in the paddy field and repair of UV disinfected secondary effluent. Average concentrations of Microorganisms were maintained by more than about 1,000 MPN/100mL in paddy field after irrigation. Microorganism repair was evaluated in relation to UV dose in photoreactivating light and dark. In addition, a significant inverse relationship was found between UV dose and repair of indicator microorganisms when the research of wastewater was conducted in the condition of low and high UV dose.

• 상하수도학회지
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• 제10권2호
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• pp.70-79
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• 1996

Ultrafiltration(UF) and powdered activated carbon(PAC) adsorption were combined to treat wastewater contaminated with refractory organic compounds. Secondary sewage effluent of RBC process was used for the investigation. It was determined from batch test results that a contact time of 2 hours and a PAC dose of 450mg/l would be used in the experiments. Backwashing was accomplished by forcing the permeates back ward with pressure of $2.5kgf/m^2$ for 90 seconds. It was shown that refractory organics removal by the PAC-UF process was more efficient than UF process without PAC pretreatments. As backwashing frequency was decreased from four times to one time in an hour, the removal efficiency was significantly increased. The addition of PAC to the UF process mitigated the fluctuation of filtrate quality which was increased in UF process without PAC treatment as transmembrane pressure was increased.

• 한국습지학회지
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• 제18권4호
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• pp.357-362
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• 2016

생물학적 처리공정의 이차침전지의 고액분리 효율 증대는 전체 시스템 운전의 효율를 증대시키는 것으로 알려져 있다. 하수처리장 방류수 SS는 대부분 유기물질로 구성되어 있어 이차침전지 방류수에서 SS성분을 낮추기 위해서는 이 성분을 구성하는 미세 SS성분을 자체 응집(self flocculation)을 통해서 그 크기와 무게를 증대시켜 이들의 침전을 통해서 제거할 수 있다, 이에 이차침전지내에 이중정류벽 설치를 통한 이차침전지 유출수 부유물질 (SS) 농도 감소를 확인하였고, 유입수의 일간 변화에 의해 하수가 급격히 증가할 경우 유량변동에 따른 충격부하에 의한 유출 부유물질이 안정적으로 처리되는 것을 확인하였다. 따라서 장방향 이차침전지 부유물질 저감을 위해 자체응집을 시킬 수 있는 시설물의 설치가 필요하다.

• Environmental Engineering Research
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• 제19권1호
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• pp.75-81
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• 2014

Methanotrophic denitrification under a non-aerated condition (without external supply of oxygen or air) was investigated in a bioreactor coupled with a membrane diffuser. Batch experiment demonstrated that both methane consumption and nitrogen production rates were not high in the absence of oxygen, but most of the nitrate was reduced into $N_2$ with 88% recovery efficiency. The methane utilized for nitrate reduction was determined at 1.63 mmol $CH_4$/mmol $NO_3{^-}$-N, which was 2.6 times higher than the theoretical value. In spite of no oxygen supply, methanotrophic denitrification was well performed in the bioreactor, due to enhanced mass transfer of the methane by the membrane diffuser and utilization of oxygen remaining in the influent. The denitrification efficiency and specific denitrification rate were 47% and 1.69 mg $NO_3{^-}-N/g\;VSS{\cdot}hr$, respectively, which were slightly lower than for methanotrophic denitrification under an aerobic condition. The average concentration of total organic carbon in the effluent was as low as 2.45 mg/L, which indicates that it can be applicable as a post-denitrification method for the reclamation of secondary wastewater effluent. The dominant fatty acid methyl ester of mixed culture in the bioreactor was $C_{16:1{\omega}7c}$ and $C_{18:1{\omega}7c}$, which was predominantly found in type I and II methanotrophs, respectively. This study presents the potential of methanotrophic denitrification without externally excess oxygen supply as a post-denitrification option for various water treatment or reclamation.

• Journal of Animal Science and Technology
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• 제48권2호
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• pp.315-324
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• 2006

This research was conducted to clarify the characteristics of electrochemical decolorization of effluent discharged from a biological animal wastewater treatment process and to finally establish parameters or mode for optimum operation of electrolysis system. Average color unit of wastewater was about 1,200 and DSA(Dimensionally Stable Anode) was used as electrode. Experiments were performed with two different operation conditions or modes, fixed voltage-free current(Run A) and free voltage-fixed current(Run B). Color removal rate was proportional to the electrode area and electrical conductivity, and an equation subject to them at a condition of fixed voltage was derived as follows; Ct=C0ekt, k=[{0.0121×ａ(dm2)× c(mS/cm)}+0.0288], [where, C0: initial color, Ct: color unit after treatment for t, k: reaction coefficient, t: time(min.), ａ: electrode area, c: conductivity]. From the study on the effects of current density on color removal, it was revealed that the removal efficiency of color was function of the current density, showing direct proportion. However, when considered energy consumption rate, maintenance of low current density was an economical way. Based on the obtained results, it was concluded that supplementation of electrolyte is not necessary for the removal of color from the effluent of secondary treatment process and operation with the mode of free voltage-fixed current, rather than operation with fixed voltage-free current mode, would be an efficient way to increase the removal performance and capacity per consumed energy.

• 상하수도학회지
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• 제24권2호
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• pp.219-230
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• 2010

Computer simulation has been widely used to design and optimize the operation of wastewater treatment plants since 1980. For secondary clarifiers, the simulation has been a tool to optimize the performance by providing dimensions for flocculation well. However, there has been no attempt to find the optimized geometrical parameters in circular secondary clarifier using simulation tools. In this study, three SVIs (Sludge Volume Indexes), two well types (feed and flocculation wells), 8 SWDs (Side Water Depths) and 9 bottom slopes were variables for simulation. Diurnal inflow and associated MLSS (Mixed Liquor Suspended Solid) concentrations were used for input loadings. When flocculation well was installed, 48% less concentration at lowest ESS (Effluent Suspended Solid) concentrations was produced and the diurnal ESS concentration range had been reduced by 52%. From these results, flocculation well must be installed to produce lower and stable ESS from circular secondary clarifiers. Under same loading conditions with $300m{\ell}$/g of SVI, The lowest ESS was produced when SWD was 4.5m with 4% of bottom slope. Therefore, SWD and bottom slope must not be deeper than 4.5m and must be near 4%, respectively, in circular clarifier with flocculation well to produce the lowest ESS concentration.

• Advances in environmental research
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• 제7권1호
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• pp.39-52
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• 2018

Direct membrane filtration (DMF) of wastewater has many advantages over conventional biological wastewater treatment processes. DMF is not only compact, but potentially energy efficient due to the lack of biological aeration. It also produces more biosolids that can be used to produce methane gas through anaerobic digestion. Most of ammoniacal nitrogen in wastewater is preserved in effluent and is used as fertilizer when effluent is recycled for irrigation. In this study, a technical feasibility of DMF was explored. Organic and nitrogen removal efficiencies were compared between DMF and membrane bioreactor (MBR). Despite the extremely high F/V ratio, e.g., $14.4kg\;COD/m^3/d$, DMF provided very high COD removal efficiencies at ~93%. Soluble microbial products (SMP) and extracellular polymeric substances (EPS) were less in DMF sludge, but membrane fouling rate was far greater than in MBR. The diversity of microbial community in DMF appeared very narrow based on the morphological observation using optical microscope. On the contrary, highly diverse microbial community was observed in the MBR. Microorganisms tended to form jelly globs and attach on reactor wall in DMF. FT-IR study revealed that the biological globs were structurally supported by feather-like materials made of secondary amines. Confocal laser scanning microscopy (CLSM) study showed microorganisms mainly resided on the external surface of microbial globs rather than the internal spaces.

• 공업화학
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• 제31권1호
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• pp.90-96
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• 2020

본 연구는 혼합비료를 유도용액으로 하는 정삼투 기술을 하수에 적용하여 하수를 재이용하기 위한 연구이다. 이를 위하여 본 연구에서는 J 하수처리장의 1차 침전지 유입수와 유출수, 그리고 2차 침전지 유출수를 각각 처리 대상으로 하였다. 평균 수투과선속은 KCl + NH₄Cl > KCl + NH₄H₂PO₄ > KCl + (NH₄)₂HPO₄의 순서로 크게 나타났으며, 역용선속은 KCl + NH₄H₂PO₄ < KCl + NH₄Cl < KCl + (NH₄)₂HPO₄의 순서로 작게 나타났다. 혼합비료의 종류에 관계없이 2차 침전지 유출수의 수투과선속이 가장 높게 나타났다. KCl과 NH₄H₂PO₄의 혼합 유도용액은 비료의 주요 성분인 질소, 인 및 칼륨을 모두 포함하고 있을 뿐 아니라 낮은 비역용질 선속을 갖고 있어서 하수의 재이용에 가장 유용하게 사용될 수 있을 것으로 판단되었다. KCl과 NH₄H₂PO₄의 혼합 유도용액을 사용한 경우, 2차 침전지 유출수에 대한 평균 수투과선속과 역용질선속은 각각 12.14 LMH과 0.012 mol/㎡s이었다.