• 해양환경안전학회지
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• 제14권2호
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• pp.105-109
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• 2008

우리나라에서 대부분의 호수는 인이 제한영양염인 것으로 나타나고 있다. 그러므로 인의 제거는 하수처리에서 중요한 공정이라고 할 수 있다. 그러나 많은 하수처리장은 재래식처리공정으로 처리하고 있으며 인의 제거율이 $10{\sim}30%$로 낮게 나타나 인의 제거공정은 필요하게 되었으며 패각은 수중의 인을 제거할 수 있는 것으로 알려지고 있어서 인의 활용이 주목된다. 회분식으로 패각을 이용하여 인의 제거율을 조사한 결과 패각의 크기가 작을수록, pH가 높을수록 제거율이 높게 나타났다. 또한 칼슘의 주입농도를 달리하여 처리한 결과 칼슘의 농도가 높을수록 처리효율이 증가하였으며 칼슘의 농도를 20mg/L로 조절하여 실험한 결과 2시간 내에 90% 이상의 제거율을 나타내었다. 재순환을을 변화시켜 실험한 결과 재순환율이 증가할수록 제거율은 증가하였으며 PH 11에서 재순환율을 300%로 조절한 결과 인의 제거율은 80%가 되었다. 중탄신이온의 영향을 평가하기 위하여 중탄산이온의 농도를 달리하여 실험한 결과 중탄산이온의 증가에 따라 인의 제거율은 감소하는 것으로 나타났으며 감소하는 비율은 지수함수로 나타났다.

• 상하수도학회지
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• 제24권4호
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• pp.463-474
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• 2010

In this study, chemical coagulation conditions for treating combined sewer overflow(CSO) occurred during rainy season were evaluated by jar tests with aluminum sulfate[$Al_2(SO_4)_3{\cdot}17H_2O$] and ferric chloride[$FeCl_3{\cdot}6H_2O$]. The raw domestic sewage sampled from the primary sedimentation tank at a local sewage treatment plant was filtered through $150{\mu}m$ sieve before using. Point of zero charge(PZC) for various dose of aluminum sulfate occurred at pH 5.8-6.5, while for ferric chloride occurred at pH 5.3-6.0 in term of streaming current(SC) values. Charge neutralization ability of aluminum sulfate was bigger than that of ferric chloride. Optimum pH and dose of aluminum sulfate and ferric chloride were 6.2, 0.438mM and 5.8, 0.925mM, respectively. Removal efficiencies of TCOD, turbidity, SS and TP were 75, 97, 95, 96% with aluminum sulfate and 74, 96, 98, 99% with ferric chloride at their optimum coagulation conditions. More efficient removal of SS, TP and small particles was possible with ferric chloride at optimum coagulation conditions. Both SC values and COD removal started to increase where soluble phosphorus was completely removed.

• 한국미생물·생명공학회지
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• 제40권4호
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• pp.424-429
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• 2012

The intention of this research was to investigate the solubilization of primary sewage sludge using lactic acid bacteria cultured in a glucose and yeast extract medium. Glucose as the carbon source and yeast extract as the source of nitrogen were chosen as an economic medium with the potential for the mass production of lactic acid bacteria. The optimal concentrations of the medium were 3% (w/v) glucose and 2% (w/v) yeast extract. In this study, in order to improve field applications for the solubilization of sludge at sewage treatment plants, a powdered form of lactic acid bacteria was produced. The optimal inoculum of the powder for the maximum efficiency of solubilization was 1% (w/v). In that condition, the SCOD value increased from 8600 (mg/L) at the beginning of experiment to 10290 (mg/L) at 96 h, with the highest solubilization rate (20.6% DDCOD) and 11.2% (SCOD). Also, the TVFAs of the lactic acid bacteria inoculation group were produced more than that of the control group. In particular, acetic acid was produced 5 times more in the experimental group than in the control group. In this research, the potential of lactic acid bacteria in the pretreatment of primary sewage sludge as a solubilizer, and as an energy source producer for microbial fuel cells was revealed.

• 상하수도학회지
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• 제18권5호
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• pp.619-627
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• 2004

Purposes of this study were to examine closely the extracellular polymeric substances (EPS) which was a membrane fouling contaminant, to control detected EPS by powdered activated carbon (PAC) dosage etc. and to evaluate the possibility of practical reuse facility. With high removal efficiency of general pollutants, when the PAC is added to MBR, improvement of removal efficiency of $COD_{cr}$, and color was expected and treated wastewater can be reused. It was judged that the correlation between EPS and membrane fouling was very high. Carbohydrate and DNA in the EPS were judged to be cause of membrane fouling. If EPS could be controled, not only membrane fouling would be decreased but also operation time would be extended. In experiment of powdered activated carbon (PAC), characteristics of the best PAC for membrane fouling control were the particle size of $7{\mu}m$, lodine Number of 1,050, surface area of peat of $1,150m^2/g$. In lab test, operation time of MBR by PAC dosage of 200mg/gVSS was longer than one of MBR by without PAC dosage. Because EPS, especially carbohydrate and DNA, was controled successfully by PAC, membrane fouling in MBR could be decreased.

• 한국미생물·생명공학회지
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• 제36권3호
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• pp.233-239
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• 2008

A new approach to the solubilization of excess activated sludge by the inoculation of lactic acid bacteria was studied to reduce the amount of sludge produced in the activated sludge treatment process. Aerobic microorganism in sludge was lysed in anaerobic condition and the cytoplasmic substance eluted was utilized as a carbon source by lactic acid bacteria. On the basis of sludge solubilization efficiency, Lactobacillus brevis and Leuconostoc mesenteroides subsp mesenteroides were selected the best candidates among five kinds of Lactobacillus sp. and seven kinds of Leuconostoc sp. The sludge solubilization efficiency by heterofermentative lactic acid bacteria was more efficient than that of homofermentative bacteria. Initial value of soluble COD (sCOD) was 1050 mg/L at the initial inoculation time increased to 3070 mg/L (192% solubilization) at 96 h of the incubation time. The inoculation of lactobacillus brevis to the sludge resulted in 2824% increase in sCOD value after 96 h of incubation than the control experiment. Leuconostoc mesenteroides subsp mesenteroides showed 152% increase of solubilization and 30% increase of S-COD/T-COD on 96 h of incubation time. Considering the increase of S-COD by the inoculation of Leuconostoc sp. on 24 h, 10% inoculation of lactic acid bacteria to the sludge was most effective.

• 도시과학
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• 제8권2호
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• pp.1-5
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• 2019

China is the great powers of use and production of antibiotics.The current process of sewage treatment plants can not effectively remove antibiotics in water. Chinese scholars have detected different kinds of antibiotics in major waters of the country, which have potential harm to human body. Among all kinds of antibiotic treatment technologies, adsorption removal technology has the advantages of simple operation, low cost and high removal efficiency. It is a widely concerned antibiotic removal technology. However, at present, few materials have been put into practical application, and more materials with low cost and high efficiency need to be found. Different adsorptive materials have different adsorptivity to different antibiotics. For different antibiotics, different adsorptive materials can be integrated in the future, and the theory can be extended to application.

• 환경위생공학
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• 제24권1호
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• pp.13-24
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• 2009

ASA공정은 유입수를 혐기조와 무산소조에 분배하여 유입시킴으로써 반송슬러지에 영양 물질을 공급하여 슬러지의 안정화 및 인 방출을 유도하고, 후속 호기조에서 유기물 제거, 인 과잉섭취 및 질산화를 조장하며, 무산소조에서는 내부반송을 하지 않고 폐수의 탄소원을 이용하여 탈질함으로써 내생탈질을 증가시키는 공법이다. 본 연구에서는 가정오수에 ASA공정을 적용하여 유입수의 분배비와 체류시간이 처리효율에 미치는 영향을 파악하였다. 유입수 분배비와 HRT는 BOD 제거에 큰 영향을 미치지 않았고 BOD 제거율은 운전기간 동안 92.0% 이상 안정적으로 유지되었다. 유입수 분배비가 4:6일 때에는 질소제거율이 82.6%, 9:1일 때에는 인제거율이 67.8%로서 가장 높게 나타났다. ASA공정에 의한 가정오수처리에서 유입수의 분배비는 6:4, HRT는 8hr일 때 제거율이 가장 양호하였으며, 이때 질소, 인제거율은 각각 82.6%와 59.5%이었다.

• 한국물환경학회지
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• 제33권1호
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• pp.90-96
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• 2017

Many sewage treatment plants have applied the advanced technology of chemical coagulant system to remove phosporus in Korea. However there are some problems for the injection of optimum coagulant dosage. In order to solve these problems, the research related to the more cost-effective automatic total phosphorus coagulation control system using an EC(Electrical Conductivity) have been in progress. This study was conducted by the same process and operation method as the Lab-scale for public small town sewage treatment plant. First, it confirmed the correlation among the EC, PO4-P and coagulant dosage in the Lab-scale MSBR(Membrane Sequencing Batch Reactor) process. Next, it analyzed that correlation coefficient of EC and the coagulant dosage was 0.92 in the Full-scale MSBR process. As a result, not only T-P removal efficiency was doubled but also it satisfied the effluent water quality standard in a stable manner. In addition, by applying the automatic control system using the EC, compared to the fixed coagulant injection system the coagulant dosage could be reduced by 28%.

• 한국산학기술학회논문지
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• 제12권7호
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• pp.3341-3352
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• 2011

본 연구는 간헐적으로 공장폐수가 유입되고 있는 하수처리시설에 대하여 각 단위공정별 운전현황 조사와 수질 측정을 실시하여 운전특성을 파악하고자 하였다. 생물반응조의 운전조건은 MLSS 농도 2,000~3,000 mg/L, HRT 5.3~16.3 시간, SRT 2.8~66.6 일 범위를 나타내었고, SVI는, 최적 범위인 50~150을 상회하여, 200 이상의 측정값이 빈번히 발생하여 슬러지 침강성이 양호하지 않은 것으로 관측되었다. 주요 원인은 공장폐수의 유입에 기인한 것으로 판단되며, 이와 같이 공장폐수 유입 시 생물반응조내의 MLDO가 급격히 상승하고 질산화 효율이 빠르게 감소하며 이차침전지에서는 Pin floc.이 유출되는 현상이 발생하였다. 미생물 관측결과, 다양한 세균 플록과 섬모충류 등이 관측되었으나, Bulking 발생의 원인이 되는 사상균인 Sphaeotilus와 방선균 등도 발견되었다. 단위공정별 처리효율은 평균적으로는 대체로 양호한 처리효율을 나타내고 있었으나 간헐적인 공장폐수 유입의 영향으로 인한 생물반응조의 운전특성의 불안정성으로, 처리효율의 변동성이 크게 나타나고 있었다.

• 한국물환경학회지
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• 제35권2호
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• pp.145-151
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• 2019

The purpose of this study was to investigate treatment characteristics of diatomite filtration, that would allow water recovery from biologically-treated effluent for reuse. Diatomite, Celpure 100, and acid clay were used as filter-aids, with a support filter manufactured from polyethylene (PE), and polypropylene (PP). This pre-coating process using diatomite filter-aids, is used in the filtration range of pressure filters, and has consistently provided high-quality separation. The results showed that variations in average removal efficiency of SS, and T-P from biologically treated effluent by the diatomite-coated PE filter, were approximately 82.2 ~ 88.9 % and 4.8 ~ 21.1 %, respectively. T-P treatment efficiency of the PP filter pre-coated with diatomite and $Celpure^{(R)}100$ at $57.64g/m^2$, was approximately $24{\pm}10%$ and $40{\pm}15%$ on average, respectively. Particle size distribution of secondary effluent varied from 0.05 to $200{\mu}m$, and $d_{50}$ value was $20.76{\mu}m$. The size distribution of particles in the diatomite filtrate ranged from 1.26 to $101.1{\mu}m$ when pre-coated with diatomite filter-aid, at a content of $57.64g/m^2$. Diatomite filter aids, i.e., the particles that form the pre-coating layer, capture very fine particles as well as macromolecules, owing to their complex structure with numerous fine microscopic pores, and surface properties. The filtration process using diatomite and $Celpure^{(R)}100$ as filter aids, has been successfully applied, to recover water from sewage for reuse. The disadvantage of the process, is that the particle size of the filter-aid is spent, because of pressurization.