• 수도
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• s.1
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• pp.9-14
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• 1974

• Journal of Korean Society of Environmental Engineers
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• v.35 no.12
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• pp.918-928
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• 2013

The inequitable flow distribution to flocculation basins is an important problem faced in many water treatment plants. This is caused by the structure of a distribution channel, the height differences of outlet weirs etc. But, a modified approach for the structures has no effectiveness to achieve flow equality. The aim of this study is to reduce the inequality by adopting optimized inlet valve opening (%) of the flocculation basins using DOE (Design of Experiments) and RSA (Response Surface Analysis). The inlet valve openings (%) and inflow distributions (%) of 6 paralleled basins were set as factors (X) and characteristics(Y) respectively. 2 level factorial experiments and RSA were conducted for optimization and regression analysis (Y = f(X) + Const.). Adopting the optimized inlet valve opening (%) at field, standard deviation of flow distribution (%) and effluent turbidity was declined from 3.80% to 0.42% and from 0.29 NTU to 0.03 NTU respectively.

• Membrane Journal
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• v.23 no.1
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• pp.12-23
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• 2013

On the subject of river bed water in Seomjin river, it had accomplished the verifying experiment of membrane filtration pilot plant for evaluating the applicability of its process throughout the prediction of membrane fouling as a function of the pore size of membrane and the determination of optimum coagulant dosage. On the result of the experiment for the evaluation of the membrane fouling as a function of the pore size, a increasing rate of irreversible resistance of membrane pore size $0.1{\mu}m$ and $0.01{\mu}m$ was measured each $0.44{\times}10^{12}/m^2$ and $0.42{\times}10^{12}/m^2$, respectively. And on the result of Flux-test, it showed that the optimum coagulant dosage was measured lower than the it of the Jar-test. The result to be operated in a condition of a permeate flux $1.0{\sim}1.5m^3/m^2{\cdot}day$ without coagulation and a permeate flux $1.0{\sim}2.0m^3/m^2{\cdot}day$ with coagulation was maintained at stable trans-membrane pressure (TMP) value for 6 months up to. Therefore it showed that the stable operation without the coagulation was possible on permeate flux $1.0{\sim}1.5m^3/m^2{\cdot}day$ in the operation of membrane filtration process.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.12
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• pp.883-888
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• 2013

Coagulation and sedimentation tests were conducted with clay and three different coagulants of soil origin (AC-A, AC-B, AC-C) to determine optimal coagulant types and doses to remove algae in stagnant water bodies such as reservoirs. Raw water had an algal density of 2,950 cells/mL and was dominated by Cyanobacteria. Removal rates of algal density by clay (50 mg/L) were 49% and 85% after 10 and 30 minutes sedimentation, respectively. Other natural coagulants achieved 80-90% removal in 10 minutes and 89-94% removal in 30 minutes of sedimentation after adding 20 mg/L each. AC-A was the optimal coagulant from this study considering algal removal rates and other water quality parameters such as turbidity and pH. For the same removal rates of algae, raw waters with higher algal densities required higher coagulant doses although no strong corelation was observed. The coagulants of soil origin did not impact orgnic contents and pH of raw water, but remove phosphate up to 70%.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.197-197
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• 2019

총인처리시설에서는 응집제를 주입하여 인이나 오염물질을 침전시켜 처리하고 있으며 PAC(poly aluminum chloride)나 $FeCl_3$, $Al_2(SO_4)_3$, 등 다양한 종류의 응집제가 사용되어지고 있다. 하지만 기존에 사용되어 지고 있는 알루미늄계열의 응집제는 처리수에 잔류이온이 존재하게 되어 인체에 축적돼 알츠하이머 병 등 신체질환을 유발할 수 있는 단점이 있다. 따라서 이러한 단점을 사전에 예방하기 위해 $TiCl_4$와 같은 티타늄계열 응집제에 대한 연구가 진행되고 있다. $TiCl_4$ 응집제는 인 제거에 효과적으로 적용할 수 있으며 수중에 잔류이온을 유발하지 않으며 Ti이온은 치과임플란트나 의료장비로 사용될 만큼 인체에 무해하다고 알려져 있다. 응집제 사용에 따라 생성된 응집슬러지의 처리방안에 있어서 기존 응집제의 경우 생성된 슬러지의 대부분은 하수슬러지 위탁처리업체를 통해 소각 및 매립, 재활용 되고 있으나, $TiCl_4$를 응집제로 사용할 경우 생성된 슬러지를 인발하여 건조 및 소성을 통해 이산화티타늄으로 재활용할 수 있어 슬러지를 친환경적으로 처리가 가능해 기존 슬러지 처리방안의 경제적, 환경적 부담을 줄일 수 있는 장점이 있다. 따라서 본 연구에서는 $TiCl_4$를 하수처리장 방류수에 주입하여 수중의 총인(T-P)을 처리한 후 생성된 슬러지를 인발하여 건조와 소성과정을 거쳐 이산화티타늄을 제조하였다. 방류수를 취수해 2.5mg/L의 초기 총인 농도를 가진 원수를 제조하였으며 제조된 원수에 $TiCl_4$를 0.6mL 주입하였을 때 99.93%의 총인제거효율을 얻을 수 있었다. 응집 실험 후 생성된 슬러지를 인발하여 건조 후 $300{\sim}1000^{\circ}C$의 각각 다른 온도조건에서 소성하여 이산화티타늄을 제조하였으며, SEM과 XRD를 통해 제조된 이산화티타늄의 표면특성과 결정성 분석을 실시하였다. 제조된 이산화티타늄은 $500{\sim}800^{\circ}C$에서는 아나타제, $900{\sim}1000^{\circ}C$에서는 루타일 결정구조가 나타났다. 또한, $TiCl_4$ 주입량에 따른 이산화티타늄의 최종 생산량과 제조 시 사용되는 건조로 및 소성로의 경제적 비용 등을 고려하여 이산화티타늄 1Ton을 제조하기 위해 필요한 단가를 산출하였다. 본 연구에서 제조된 이산화티타늄 1kg의 생산단가는 약 5,400원으로 나타났으며, 가장 많이 사용되는 P-25 광촉매 보다 저렴한 가격으로 제조 및 판매를 기대할 수 있다. 따라서 하수처리장에 적용 시 기존 응집제 보다 비싼 $TiCl_4$ 비용을 보완하고 친환경적인 슬러지 처리로 제조된 이산화티타늄의 유통 및 현장적용을 통해 경제적, 환경적으로 우수하다고 판단된다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.11a
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• pp.244-245
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• 2013

본 논문에서는 회귀도 기반의 중요도 검출 기법을 제안한다. 제안하는 기법은 각 군집의 분포 정보를 이용하여 중요도를 검출한다. 우선, 이를 입력 영상에 군집 기법을 수행한다. 그리고 각 군집의 분포를 분석하여 각 군집에 대한 회귀도, 응집도, 그리고 중심밀집도를 추출한다. 마지막으로 회귀도, 응집도, 그리고 중심밀집도를 곱함으로써 중요도를 검출한다. 실험 결과 제안하는 알고리즘이 기존의 기법들 보다 중요도를 정확하게 검출하는 것을 확인할 수 있다.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1813-1817
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• 2008

유체의 특성을 나타내는 인자 중에 침강속도에 큰 영향을 미치는 인자 중 하나는 염도(salinity)이다. 염도는 부유사 입자의 응집을 촉진시키고, 입자의 응집은 더욱 큰 침강속도를 초래하는 것으로 알려지고 있다. 본 연구에서는 유체의 염도가 침강특성에 미치는 영향을 파악하기 위하여 서로 다른 염도조건(담수와 염수)에서 고령토 퇴적물에 대한 침강실험을 수행하고, 그 결과를 비교 분석하여 염도가 침강특성에 미치는 영향을 정성적 정량적으로 해석하였다.

• Journal of the Korean GEO-environmental Society
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• v.5 no.4
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• pp.5-11
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• 2004

When settled sediments in natural condition for long time were dredged by dredging process, it is natural that bulking change between sediments and dredged soils is affected by chemical injection; coagulant. Dredged sediments used in this study were sampled in the lagoon "Young rang lake" located at the east coast Sokcho city and the bulking change of dredged soils is quantitatively analysed by changing of the clay content and the amount of the flocculant and coagulant. From the experimental results, the bulking of dredged soils increased 1.69 times on the average bulking of settled sediments in natural condition in the case of the optimum chemicals addition.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.3
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• pp.337-344
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• 2006

Characteristics of flocculent aggregates have great effects on membrane fouling. Floc from kaolin particles gave higher permeate throughputs than floc from natural particles at the same conditions. Therefore, the objectives of this study are to thoroughly analyze characteristics of flocculated aggregates and to investigate effects of flocculated aggregates on membrane fouling. Image analysis, specific rake resistance and cake compressibility were used for characterization of flocs. Different flocculent aggregates formed with natural and kaolin particles were employed in this study. The fractal dimensions from the image analysis were $D_2=1.79{\pm}0.07$ for floc from natural particles and $D_2=1.84{\pm}0.06$ for floc from kaolin particles. The lower fractal dimension($D_2$) of floc from natural particles indicated that the aggregates were more porous and less compact than floe from kaolin particles. In addition, both the specific cake resistances and compressible degrees of flocs from natural particles showed greater values than those of flocs from kaolin particles. The results implied that the porous and loose flocs from natural particles were more easily compressed on membrane surface than the dense and compact flocs from kaolin particles. The compressed flocs yielded the great hydraulic resistances by hindering the water flow through the cake layer.

• Journal of the Korean Wood Science and Technology
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• v.47 no.6
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• pp.709-720
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• 2019

Due to global warming and abnormal climate, the incidence and scale of green tracts in rivers and water intake dam are increasing every year. Therefore, in this study, developed eco friendly positively charged Torrefied Wood Flour(TWF) coagulant by reusing wood damaged by blight as a natural material. In order to evaluate the effect of coagulant on water ecosystem, green algae contaminated water was collected and TOC showed high removal rate of 86% ~ 92% under 1% and 5% TWF C-PAM treatment condition. The $NH_3-N$ showed 53% removal efficiency. The average pH of the polluted water was 7.9 in the case of hydrogen ion concentration, and the pH of the treated water was in the range of 6.5 ~ 7.7, It was found to be suitable for water quality standards. In ecotoxicity tests, all the results of the experiment showed that both the number of green algae and that of treated water were not affected by the survival of the daphnia. Therefore, as a result of the analyzing, developed paste type TWF coagulants is considered to be able to remove algae using natural resources.