• Journal of Aquaculture
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• v.6 no.4
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• pp.323-338
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• 1993

The primary objective of this study was to examine the toxic effects of PCP on activated sludge and to analyze its metabolic responses while treating wastewater containing pentachlorophenol (PCP) in a sequencing batch reactor (SBR) system operating under different control strategies. This study was conducted in two phases 1 and 2 (8-hr and 12-hr cycles). Each phase was operated with two control strategies I and II. Strategy I (reactor 1) involved rapid addition (5 minutes to complete) of substrate to the reactor with continuous mixing but no aeration for 2 hours. Strategy II (reactor 2) involved adding the feed continuously during the first 2 hours of the cycle when the system was mixed but not aerated. During both phases each reactor was operated at a sludge age of 15 days. The synthetic wastewater was used as a feed. The COD of the feed solution was about 380 mg/L. After the reference response for both reactors was established, the steady state response of each system was established for PCP feed concentrations of 0.1 mg/L, 1.0 mg/L, and 5.0 mg/L in SBR systems operating on both 8-hr and 12-hr cycles. Soluble COD removal was not inhibited at any feed PCP concentrations used. At 5.0 mg/L feed PCP concentration and in SBR systems operating on phase 2, the concentrations or ML VSS were decreased; selective pressure on the mixed biomass might be increased, narrowing the range of possible ecological responses; the settleability of activated sludge was poor; the SOURs were increased, showing that the systems were shocked. Nitrification was made to some extent at all concentrations of feed PCP in SBR systems operating on phase 2 whereas in SBR systems operating on phase 1 little nitrification was observed. Then, nitrification will be delayed as much as soluble COD removal is retarded due to PCP inhibition effects. Enhanced biological phosphorus removal occurring in the system operating with control strategy I during phase 1 of this work and in the presence of low concentrations of PCP was unreliable and might cease at anytime, whereas enhanced biological phosphorus removal occurring in the system operating with either control strategy I or II during phase 2 of this work and in the presence of feed PCP concentrations up to 1.0 mg/L was reliable. When, however, such processes were exposed to 5.0 mg/L PCP dose, enhanced phosphorus removal ceased and never returned.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.8
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• pp.561-569
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• 2014

This study was carried out to get the characteristics of anaerobic digestion for chemical/biological sludge produced from municipal sewage treatment plant for phosphorus. Anaerobic mesophilic batch tests showed that the ultimate biodegradability of waste activated sludge showed 31%, PACl sludge 24%, Alum sludge 26%, respectively. At the S/I 1.0, 75% of total biodegradable volatile solids (TBVS) of waste activated sludge was degraded with an initial rapid decay coefficient, k1 of $0.1129day^{-1}$ and 74% of TBVS of PACl sludge with k1 of $0.0998day^{-1}$, and 76% of TBVS of Alum sludge with k1 of $0.1091day^{-1}$ for 20 days. During the operation of SCFMRs, the 3 reactor (Control, PACl, Alum) pH maintained 6.7~7.0 and the reactor alkalinity maintained 1,800~ 2,200 mg/L as $CaCO_3$. The average biogas production rates of SCFMRs fed with PACl sludge and Alum sludge were 0.089 v/v-d and 0.091 v/v-d, respectively, which was 27~28% lower than that of the control (0.124 v/v-d) at an HRT (hydraulic retention times) of 20 days. And the methane content during the operation ranged 70~76% in 3 reactor. The average TVS removal efficiency of SCFMRs fed with PACl sludge and Alum sludge were 19.6% and 19.9%, respectively, at an HRT of 20 days, which showed 4% lower than that of the control (23.8%). The average BVS removal efficiency of SCFMRs fed with PACl sludge and Alum sludge were 25.8% and 26.9%, respectively, at an HRT of 20 days, which was 8~9% lower than that of the control (34.5%).

• Clean Technology
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• v.12 no.2
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• pp.67-77
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• 2006

A simple dual sludge process, called as $KNR^{(R)}$ (Kwon's Nutrient Removal) system, was developed for small sewage treatment. It is a hybrid system that consists of an UMBR (Upflow multi-layer bioreactor) as anaerobic and anoxic reactor with suspended denitrifier and a post aerobic biofilm reactor, filled with pellet-like media, with attached nitrifier. To evaluate the stability and performance of this system for small sewage treatment, the pilot-scale $KNR^{(R)}$ plant with a treatment capacity of $50m^3/d$ was practically applied to the actual sewage treatment plant, which was under retrofit construction during pilot plant operation, with a capacity of $50m^3/d$ in a small rural community. The HRTs of a UMBR and a post aerobic biofilm reactor were about 4.7 h and 7.2 h, respectively. The temperature in the reactor varied from $18.1^{\circ}C$ to $28.1^{\circ}C$. The pilot plant showed stable performance even though the pilot plant had been the severe fluctuation of influent flow rate and BOD/N ratio. During a whole period of this study, average concentrations of $COD_{cr}$, $COD_{Mn}$, $BOD_5$, TN, and TP in the final effluent obtained from this system were 11.0 mg/L, 8.8 mg/L, 4.2 mg/L, 3.5 mg/L, 9.8 mg/L, and 0.87/0.17 mg/L (with/without poly aluminium chloride(PAC)), which corresponded to a removal efficiency of 95.3%, 87.6%, 96.3%, 96.5%, 68.2%, and 55.4/90.3%, respectively. Excess sludge production rates were $0.026kg-DS/m^3$-sewage and 0.220 kg-DS/kg-BOD lower 1.9 to 3.8 times than those in activated sludge based system such as $A_2O$ and Bardenpho.

• Korean Journal of Environmental Agriculture
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• v.19 no.3
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• pp.194-200
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• 2000

The amount of swine wastewater reaches about $197,000m^3$ per day at live-stock houses in the whole country. A half of the swine wastewater resources are too small to be restricted legally. This untreated wastewater causes the eutrophication in the water bodies. In case of swine wastewater treatment, the solid-liquid separation must be performed because feces(solid phase) and urine(liquid phase) have large differences in nitrogen and phosphorus concentration. It is necessary to assess exactly the concentration of the pollutants in swine wastewater for planning the wastewater treatment facilities. A full-scale operation was carried out in K city and the plant is consists of conventional plant, the supplementary flocculation basin of chemical treatment process and $anaerobic{\cdot}aerobic$ basin for nitrogen removal. The improved full-scale swine wastewater treatment plant removed the $1,500{\sim}3,000mg/l$ of total-nitrogen(T-N) to 120mg/l of T-N and $131{\sim}156mg/l$ of total-phosphorus(T-P) to $0.15{\sim}1.00mg/l$ of T-N. Accordingly, as a results of operational improvement, the removal efficiencies of T-N and T-P were over $92{\sim}96%$, 99%, respectively. The continuous supply of organic carbon sources and the state of pH played important roles for the harmonious metabolism in anaerobic basin and the pH value of anaerobic basin maintained at about 9.0 for the period of the study.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.3
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• pp.212-221
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• 2011

Wastewater treatment plants (WWTPs) are required to meet the reinforced discharge standards which are differentiated as 0.2, 0.3 and 0.5 mg-TP/L for the district I, II and III, respectively. Although most of WWTPs are operating advanced biological phosphorus removal system, the supplementary phosphorus treatment facility using chemical addition should be required almost at all WWTPs. Therefore, water quality data from several exemplary full-scale plants operating phosphorus treatment process were analyzed to evaluate the reliability of removal performance. Additionally, a series of jar tests were conducted to find optimal coagulants dose for phosphorus removal by chemical precipitation and to describe characteristics of the reaction and sludge production. Chemical costs and the increasing sludge volume in physicochemical phosphorus removal process were estimated based on the results of jar tests. The minimum coagulant (aluminium sulfate and poly aluminium chloride) doses to keep TP concentration below 0.5 and 0.2 mg/L were around 25 and 30 mg/L (as $Al_2O_3$), respectively, in the mixed liquor of activated sludge. In the tertiary treatment facility, relatively lower coagulant doses of 1/12~1/3 the minimum doses for activated sludge were required to achieve the same TP concentrations of 0.2~0.5 mg/L. Increase in suspended solids concentration due to chemical precipitates in mixed liquor was estimated at 10~11%, compared to the concentration without chemical addition. When coagulant was added into mixed liquor, chemical (aluminium sulfate) cost was estimated to be 4~10 times higher than in secondary effluent coagulation/separation process. Sludge production to be wasted was also 4~10 times higher than secondary effluent coagulation/separation process.

• Korean journal of applied entomology
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• v.15 no.1 s.26
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• pp.1-6
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• 1976

his study was conducted to investigate selective toxicity of several organophosphorous and carbamic insecticides against the small brown planthopper (Laodelphax striatellus), the white-backed planthopper (Sogatella furcifera), the brown planthopper (Nilaparvata lugensEugens), and the green rice leafhopper (Nephotetix cincticeps). The test insecticides were the organophosphoric insecticides, Diazinon$(34\%\; Ec.,\; 3\%\; G.),$ $MEP(Sumithion 50\%\; Ec.)$, and PAP(Elsan\; 47.5\%\; Ec.)$ and the carbamic insecticides. MPMC $(Meobal\; 50\%\;WP.)$, $BPMC(Bassa\; 50\%\; Ec.)$, and carbofuran $(Curaterr; 3\%\; G.)$. Toxicitiy for emulsion concentrates and wettable powders were evaluated by dipping method of rice seedlings in the laboratory and that for granulated insecticides evaluated by submerged application with potted plants in the greenhouse. In the test of contact toxicity by seedling dips, Diazinon MEP and PAP showed significantly low toxicity to the brown planthopper and MEP to the green rice leafhopper. In the test of submerged application, Carbofuran showed almost equal toxicity to the four species of the hoppers, but Diazinon was greatly less toxic to the brown planthopper. In general. the organophosphorous insecticides tested seemed to be selective in toxicity to the species of the hoppers, while the carbamic insecticides being less selective. The carbamic insecticides such as MPMC, BPMC and Carbofuran were almost equal in toxicity to the four species of the hoppers tested.

• Korean Journal of Environment and Ecology
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• v.19 no.2
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• pp.150-161
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• 2005

Soraksan National Park and Odaesan National Park, that are 20.7 km apart, should play an important role as habitats and corridors for wildlife because they are located in the center of Baekdudaegan. However, landscape features such as small area, fragmentation, and geographic isolation seem to impede the proper ecological functions of these two national parks. Using GIS technique, we examined the pattern of fragmentation in these two national parks and adjacent regions (Sokcho-si, Goseong-gun, Inje-gun, Yangyang-gun, and Hongcheon-gun) encompassing a total of $4573.5km^2$ in area. We then selected the patches suitable for an endangered carnivorous species, leopard cat, based on habitat conditions, and identified the network and stepping stone among patches to enable leopard cats to migrate. Diverse roads and artificial facilities in the study area generated a total of 24,701 patches: 39 patches among these were selected as potential habitats upon considering the habitat condition such as vegetation types and minimum area for leopard cat. Three patches nearby Gyebangsan and Bangtaesan were identified as a potential network center to relieve the effects of fragmentation and isolation of the two national parks. Our results also showed that patches containing Jombongsan and Bangtaesan would act as a source patch from there leopard cats can disperse to both national parks. It is an urgent task to identify the pattern of fragmentation and the connectivity between patches in national parks and adjacent areas for wildlife conservation because almost all national parks confront land- scape problems similar to the two national parks examined in this study.

• 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.

• Journal of Chest Surgery
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• v.30 no.2
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• pp.172-178
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• 1997

We present a etrospective analysis of arterial embolectomies performed at the Inje University Seoul Paik Hospital. During the period of March 1987 Feburary 1996 twenty-six patients underwent embolectomies, eighteen patients were male and eight patients were female, mean age of patients was 56.8 years. Rest pain was the chief complaint in 24 patients, the remaining two patients complained of long term history of claudication after recovery of acute symtoms. But only 10 patients had sensBrylmotor symtoms. Heart was the most common source of embolization and frequent predisposing factor of embolism was ischemic heart disease in 8 cases and valvular heart disease in 11 cases. The sites of embolization were upper extremities artery in 6 cases, saddle embolism in 2 cases, lower extremities artery in 18 cases and the most common site of embolism was femoral artery in 1 1 cases. Preoperative angiography was taken in the diagnosis and planning of the embolectomy in 1) patients while in the other patient p eoperative angiography was not taken. Only two cases were operated within the golden period of 6 hours and other cases were operated in more than 6 hours after embolization. In all patients, the Fogarty embolectomy catheter was used without bypass surgery via bachial ateriotomy in the embolism of upper extremities artery, bilateral groin approaches in the saddle embolism and transfemoral approach in the embolism of lower extremities artery. However 3 patients were re-operated via transpopliteal approach in the distal poplitiotibial embolism. Eighteen patients received perioperative anticoagulation therapy by heparin or fraxiparine and wafarin was used in 17 patients at the time of discharge and the indication of anticogulation was patients of valvular heat disease andfor atrial fibrillation, peripheral artery atherosclerosis and recurrent embolism. Postoperative results of the embolectomy were as follows: fouteen pateints had excellent results, five cases had symtom improvement after re-operation, B. K. amputation in 1 case who had severe atherosclerosis of lower extremities, recurrent embolism in 1 case and death in 2 cases the cause of death were acute renal failure and cerebral artery embolism, respectively. The complications of the embolectomy were reperfusion syndrome, pseudoaneurysm and intimal dissection in one case each. Conclusively the problems of embolism is delayed diagnosis and increasing number of old aged patient who had suffered from ischemic heart diease. Preoperative angiography was not always needed for embol ectomy. Selective anticoagulation therapy can decrease incidence of re-embolism. In the distal poplitiotibial embolism, embolectomy of tibial artery was difficult.

• Korean Journal of Ecology and Environment
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• v.38 no.1 s.110
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• pp.45-53
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• 2005

The environmental change of Yong-nup in Mt. Dae-Am, which is located at the northern part of Kangwon-Do, Korea, was assesed with peat sedimentary carbon and nitrogen isotope analysis. The surface layer of the peat (0 ${\sim}$ 5 cm) was 190 year BP, and the middle layers (30 ${\sim}$ 35 cm and 50 ${\sim}$ 55 cm) were 870 year BP and 1900 year BP, respectively. Bulk sedimentation rate was estimated to be about 0.4 mm $year^{-1}$ for 0 cm to 30 cm and 0.15 mm $year^{-1}$ for 35 cm to 50 cm. The $^{14}C$ age of the bottom sediment (75 ${\sim}$ 80 cm) collected and measured in this study was about 1900 year BP, although it was measured that the $^{14}C$ of the lowest bottom sediment in Yong-nup was 4105 ${\pm}$ 175 year BP (GX-23200). Since the $^{14}C$ ages for 50 ${\sim}$ 55 cm and 75 ${\sim}$ 80 cm layers were almost the same as 1890 ${\pm}$ 80 fear BP (NUTA 5364) and 1850 ${\pm}$ 90 year BP (NUTA 5462), respectively, we have estimated that the deep layers (55 ${\sim}$ 80 cm) in the high moor were the original forest soil. The low organic C and N contents in the deeper layers supported the inference. The sediment of 50 ${\sim}$ 55 cm layer contains much sandy material and showed very low organic content, suggesting the erosion (flooding) from the surrounding area. In this context, the Yong-nup, high moor, of Mt. Dae-Am, might have developed to the sampling site at about 1900 year BP. The ${\delta}^{13}C$ values of organic carbon and the ${\delta}^{15}N$ values of total nitrogen in the peat sediments fluctuated with the depths. The profile of ${\delta}^{13}C$ may indicate that the Yong-nup of Mt. Dae-Am have experienced the dry-wet and cool-warm period cycles during the development of the high moor. The ${\delta}^{15}N$ may indicate that the nitrogen cycling in the Yong-nup have changed from the closed (regeneration depending) system to the open (rain $NO_3\;^-$ and $N_2$ fixation depending) system during the development of the high moor.