• Journal of Korean Society of Environmental Engineers
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• v.34 no.2
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• pp.91-96
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• 2012

In this study we investigated the effects of operational parameters of a multi-layered soil filtration (filter depth, filtration velocity, and continuous/intermittent operation) on removal of pollutants in river water. As filter depth increased removal of all the pollutants (COD, TP, TN, and $NH_4$-N) was increased because the increase in filter depth increased in contact time between media and pollutants. The removal of TP and $NH_4$-N more increased with the increase in filter depth, comparing to the biological COD removal which was performed only in the top layer, since the removal mechanism of TP and $NH_4$-N was physicochemical process occurring throughout the whole layers. However, the reduction in filtration velocity resulted in decrease of removal all the pollutants removal due to shorter retention time. Biological COD removal was more influenced with the reduction in filtration velocity (longer retention time), than the removal of TP and $NH_4$-N. Because biological process was occurred only in the top layer which has relatively shorter retention time, comparing with physicochemical process occurred throughout whole media. Therefore, it is desirable that the operation parameters be controlled toward increasing retention time, in order to achieve efficient pollutants removal. The change in operation mode (continuos vs. intermittent operations) did not provide significant effects on the pollutant treatment efficiency by the multi-layered soil filtration system. Our findings suggest that for stable long-term operation it should be considered keeping conditions for biological activity and accelerating clogging.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.859-863
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• 2008

축산폐수, 침출수 등의 고농도 폐수를 생물학적으로 처리할 경우 최종 방류수는 강한 색도를 띠며 고분자량의 유기물질을 다량 함유한다. 이는 생물학적으로 분해하기 어려운 유기성 복합체와 생화학적 반응에 의한 중간생성물로 색도를 띠는 천연유기물질(NOM)을 포함한다. 생물학적 처리수의 색도는 심미적인 불안감, 방류수역의 수질오염 및 공중보건상의 잠재적 위해성을 갖는다. 또한, 수자원 이용측면에서 정수처리공정에서의 약품투입량 증가와 특히, 소독부산물 생성이라는 잠재적 문제점이 뒤따른다. 따라서 이러한 문제점을 해소하기 위한 생물학적 2차 처리수의 후속처리가 요구되며, 실제로 난분해성 유기물과 색도를 제거하기 위한 흡착, 막 분리, 고급산화(AOP) 및 화학적 응집 등의 물리-화학적 공정에 대한 연구가 수행되어왔다. 특히, 화학적 응집은 무기응집제 또는 고분자중합체(Polymer)를 이용하여 콜로이드성 입자와 색도를 띠는 난분해성 유기물을 전기적 불안정화를 유도함으로서 흡착 및 응집과정을 통해 제거하는 공정으로 많은 연구자들에 의해 연구되어왔다. 그러나 난분해성 유기물과 색도제거는 대상원수의 성상과 화학적 특성 등에 따라 각각의 제거효율과 최적 운전조건이 상이하게 나타난다. 화학적 응집공정은 비교적 높은 제거효율을 보이지만, 운전 및 유지관리의 기술적 어려움, 경제적 비효율성 등으로 인하여 적용에 어려움을 겪고 있는 실정이다. 본 논문에서는 생물학적 혐기-호기성 공정에서 방류되는 축산폐수의 2차 처리수를 대상으로 화학적 응집에 의한 색도 및 난분해성 유기물의 제거거동을 고찰하였다. 대상 처리수의 $TCOD_{Cr}$ 농도는 평균 410 mg/L인 반면, $BOD_5$는 7-15 mg/L 범위로 난분해성 유기물을 다량 함유하고 있음을 알 수 있었다. 이에 황산알루미늄(Aluminium sulfate; $Al_2(SO_4){\cdot}14H_2O$)과 염화철(ferric chloride)의 무기응집제를 이용하여 자 테스트(jar test)를 수행한 결과, 동일한 응집제 주입량에서 염화철의 유기물 제거 효율이 높은 것으로 나타났다. 황산알루미늄과 염화철의 경우 각각의 응집제 주입율 5.85mM에서 89%, 7.03mM에서 97.5%의 최대 유기물 제거효율을 보여주었으며, 이 때 최종 pH는 4.0-5.6 범위이었다. 한편, 대상 원수 내의 콜로이드성 입자 또는 용존성 유기물의 작용기(functional group)는 일반적으로 음으로 하전 되어 있어 응집에 의해 잘 제거되지 않는 특성을 가지고 있다. 따라서 과량의 응집제를 주입하여 다가의 양이온성 금속염을 흡착시켜 전기적으로 중화시키고, 생성된 침전성 수화물 내에 포획 또는 여과시켜 제거하게 된다. 이 때, 금속염 수화종의 전하밀도가 응집효율에 영향을 주는 것으로 알려져 있는데, 다가의 양이온은 전기적 이중층(Double layer) 압축에 의한 불안정화를 향상시킬 수 있기 때문에다. 또한, 2가 금속염은 색도유발물질과 흡착하여 humate 또는 fulvate 등의 착화합물(complex)을 형성시켜 응집효율을 향상시킬 수 있다. 따라서 본 연구에서는 생물학적 2차 처리수의 화학적 응집처리에 있어서 알루미늄염 등의 다가이온 첨가가 응집에 미치는 영향을 관찰하고, 후속되는 플록형성 및 침전공정에 의한 제거효율을 비교, 평가함으로써 2차 처리수로부터 난분해성 유기물과 색도를 보다 효과적이고 경제적으로 제거할 수 있는 최적인자를 도출하고자 하였다.

• KSBB Journal
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• v.16 no.3
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• pp.281-285
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• 2001

Biofiltration of volatile organic compounds (VOCs) was performed for 80 days in a biofilter packed with peat. The empty bed residence time was 3.2 min. for a gas mixture of isoprene, dimethyl sulfide, chloroform. benzene, trichlorethylene, toluene, m0xylene, o-xylene and styrene. After 34 days of acclimatization the removal efficiency for a 83 g/㎥ gas input was 93% at $25^{circ}C$ and 73% at $45^{circ}C$, respectively. The maximum cell density at $25^{circ}C$ was 1.12$\times$10(sup)8 cells/g. Removal efficiencies of m-xylene and toluene (91%) were better than that of benzene (86%). The first quarter of the packed column removed 60% of the incoming VOCs.

• Korean Journal of Environmental Agriculture
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• v.21 no.3
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• pp.208-215
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• 2002

This study was carried out to evaluate the pollutant removal efficiencies of the advanced drinking water treatment using activated carbon process. for raw water, Nakdong river was used. from the activated carbon adsorption experiment the fellowing results were obtained The efficiency of water treatment enhanced with increase in empty bed contact time. Variation of pH was not detected to the bed depth, but DO content gradually decreased with the bed depth. Removal efficiency of $KMnO_4$ consumption, UV254 absorption, DOC and THMFP also were increased by increasing in the bed depth. Transition of adsorption zone from upper parts of the bed to the lower parts were detected as treatment periods increased. Large portion of DOCs were degraded and removed by the microbes growing on the surface of activated carbons. Cell numbers of microbes were estimated over $1.1\times10^7\;cell/cm^3$ at the depth of 20 cm from the surface 126 days after starting operation. The results shown that the activated carbon Inter was successfully acted as a biofilm filter.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.205-205
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• 2020

도시화로 인해 불투수층의 증가는 강우시 유출을 증가시켜 물순환을 왜곡시키고 다양한 오염물질을 수계로 배출시켜 수질악화 및 수생태계를 훼손시킨다. 이러한 환경 수문학적 문제를 해결하기 위하여 침투, 여과, 저류 등의 물리적 기작, 식생 및 토양의 생물학적 기작을 이용한 LID 기술을 적용하고 있다. LID 시설에 적용되는 식물은 심미적, 경관성을 증대시켜주나, 다량의 오염물질이 유입될 경우 일부 식물의 고사를 유발한다. 따라서 본 연구는 LID 시설내 식물 체내 중금속 농도를 파악하고자 수행하였다. 본 연구는 지붕 강우유출수를 처리를 위해 설치된 LID 시설(침투화분) 모니터링 대상 지점으로 선정하였으며, 패랭이(Dianthus chinensis)와 조팝나무(Spiraea fritschiana)가 식재되어있다. LID 시설 내 식재된 식물과의 비교를 위해 패랭이와 조팝나무가 식재된 화단을 각각 대조군으로 선정하였다. 패랭이는 잎과 뿌리, 조팝나무는 줄기와 잔가지로 구분하여 체내 중금속 함량에 대해 분석을 수행하였다. 중금속 분석은 토질오염공정시험기준에 의해 Fe, Ni, Zn, As를 분석하였다. 연구결과, LID 시설에 적용된 식생과 대조군 식생의 체내 Fe 농도는 패랭이(1176.9~3804.6mg/kg), 조팝나무(218.4~342.5mg/kg)이며, Ni의 경우 패랭이(13.3~21.4mg/kg), 조팝나무(7.2~12.5mg/kg) Zn은 패랭이(33.6~160.5mg/kg), 조팝나무(46.1~243.2mg/kg), As는 패랭이(7.3~37.3mg/kg), 조팝나무(1.9~8.7mg/kg)로 대조군에 비해 유사하거나 높은 값을 보이는 것으로 분석되었다. 또한, LID 시설에 식재된 조팝나무는 대조군에 비해 줄기는 약 26배, 잔가지 19배 이상 높은 농도를 보이는 것으로 나타났으나, 중금속 농도의 차이는 식물의 중금속 흡수 혹은 토양의 중금속 흡착능력이 토양의 종류, 특성에 따라 다를 수 있기 때문에 모니터링 환경에 따라 편차가 존재할 것으로 판단된다.

• Korean Journal of Food Science and Technology
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• v.53 no.6
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• pp.749-755
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• 2021

The objective of this study was to investigate the physicochemical properties of rice starch extracted from stale rice using alkaline steeping (AKL) and improved enzymatic digestion (iENZ) methods. The crude protein content (0.5-0.7%) of stale rice starch (SRS) was less than 1% by iENZ, but not so when measured by the existing ENZ methods. SRS is an intermediate amylose rice starch. AKL-SRS and iENZ-SRS exhibited typical A-type crystal packing arrangements with similar relative crystallinities. iENZ-SRS showed higher gelatinization onset and peak temperatures with a narrower gelatinization temperature range, compared to those of AKL-SRS, indicating that iENZ annealed SRS. Thus, iENZ-SRS exhibited lower swelling power and solubility, and higher pasting viscosities with delayed viscosity development. Overall, the use of stale rice as a rice starch source could make economical production of rice starch possible, and iENZ may diversify rice starch characteristics, which expands the utilization of rice starch in food and non-food industries.

• Korean Journal of Plant Resources
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• v.28 no.5
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• pp.665-674
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• 2015

The final goal of this research is to develop a botanical biofiltration system, which combines green interior, biofiltering, and automatic irrigation, which can purify indoor air pollutants according to indoor space and the size of biofilter. The biofilter used in this experiment was designed as an integral form of water metering pump, water tank, blower, humidifier, and multi-level planting space in order to be more suitable for indoor space utilization. This study was performed to compare indoor air quality between the space adjacent to a botanical biofilter and the space away from the biofilter (control) without generation of artificial indoor air pollutants, and to evaluate plant growth depending on multiple floors within the biofilter. Each concentration of indoor air pollutants such as TVOCs, monoxide, and dioxide in the space treated with the biofilter was lower than that of control. Dracaena sanderiana ‘Vitoria’ and Epipremnum aureum ‘N Joy’ also showed normal growth responses regardless of multiple floors within the biofilter. Hence, it was confirmed that the wall-typed botanical biofilter suitable for indoor plants was effective for indoor air purification.

• KSBB Journal
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• v.16 no.6
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• pp.603-608
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• 2001

In this study, we studied on the remeval of toluene vapors in a lab-scale biofilter. Biofiltration was performed in a column fed downflow with contaminated air at ambient conditions. The column was packed with mixture of Peat and Calstene(5:3 vol. Ratio), Synthesized media, Bark and Wood chip, which were inoculated with microbial population of selected stains(Pseudomonas. putida, KCCM 11343, ATCC 12633). The microorganisms were immobilized on the bed medium and then biofilm were formed. The biofilter was operated under the conditions of various inlet toluene concentrations for 180 days and treated up to the elimination capacity of maximum 40 g/㎥hr at the inlet load of 30 g/㎥ hr with percentage removals of 20∼90% and gas retention times between 1 and 2 min. The pressure drop was very negligible through the biofilter columps because its value of 0.054 cmH$_2$O/m was much less than others. The effect of operating conditions such as flow rate, inlet toluene concentration and moisture contents on the performance of the biofilter was sequentially investigated in this study.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.4
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• pp.380-391
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• 1993

The experimental study was made to propose the treatment method of wastewater in the high-density fish culture system. The BOD to COD ratios of effluents were almost same to 0.65 in the eel-farm, but were various in the farm rearing together with tilapia etc. A BOD rate curve of the eel-farm effluent could be described mathematically by the equation, $BODu=14.1(1-10^{-0.222t})+30.9(1-10^{-0.035(t-8)})$. Nitrification in Biological Fluidized Bed(BFB) system to treat the fish-farm wastewater could be reduce ammonium level up to $65{\sim}79\%$ when ammonium loading rates were between 0.014 and 0.075g $NH_4/g$ BVS-day. Nitrification efficiency was decreased by organic matters in the wastewater when ammonium loading was low(0.014 g $NH_4/g$ BVS-day). T-N removal ratios were decreased to increase loading in denitrification process, because of low C/N ratio. Based on much higher biological mass concentrations, BFB system takes many advantages of a practical viewpoint, such as stability of treatment efficiency and reduction of necessary site area for the facility, as compared with conventional treatment systems.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.3
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• pp.175-179
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• 1979

One of the major problems in tile activated sludge system has been difficulty in separating the microbial solids from the treated effluent and in returning them to the aeration tank. Another problem has been the digestion of the excess activated sludge. In constrast, it has not been difficult to separate the microbial solids from the treated effluent from the biological fixed-film systems(RBC process, Trickling Filter, FAST process). These systems have also featured less sludge production. Recently, it was proposed to experiment with the RESMAS process in order to eliminate the settling tank and sludge concentration facilities and to reduce the quantity of excess sludge for final disposal. The effluent quality could be predicted by .the concept of the maximum accumulation capacity. However, the hydraulic characteristics of the screen media in the RESMAS reactor were not dynamic. The object of the present study is to evalute the sludge accumulation rate and effluent quality prediction in the REMSMAS process designed in the dynamic hydraulic structure. This process can eliminate the final sedimentation tank and sludge concentration tank needed in the RBC, CMAS, Trickling Filter and FAST processes. Also, the effluent quality is desirable to compare with other processes. It appeared that the value of the sludge holding capacity was higher than those of the RESMAS and FAST processes, and the periods of the critical operating time were proportional to the substrate hydraulic loadings.