• 한국환경생태학회:학술대회논문집
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• 한국환경생태학회 2003년도 추계학술논문발표회 논문집
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• pp.105-126
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• 2003

In Korea most of annual rainfall is concentrated in several episodic heavy rains during the season of summer monsoon and typhoon. Because of uneven rainfall distribution many dams have been constructed in order to secure water supply in dry seasons. The Han River system has the most dams among Korean rivers, and the river is a series of dams now. Reservoirs need different strategy of water quality control from river water. Autochthonous organic matter and phosphorus should be the major target to be controlled in lakes. In this Paper some problems are discussed that makes efforts of water quality improvement ineffective in lakes of Korea, even after the substantial investment to wastewater treatment facilities.1) Phosphorus is the key factor controlling eutrophication of lakes and the reduction ofphosphors should be the major target of water treatment. However, water quality management strategy in Korea is still stream-oriented, and focused on BOD removal from sewage. Phosphorus removal efficiency remains as low as 10-30%, because biological treatment is adopted for both secondary treatment and advanced treatment. The standard for TP concentration of the sewage treatment plant effluent is 6 mgP/l in most of regions, and 2 mg/l in enforced region near metropolitan water intake point. TP in the effluents of sewage treatment plants are usually 1-2 mg/1, and most of plants meet the effluent regulation without a further phosphorus removal process. The generous TP standard for effluents discourages further efforts to improve phosphorus removal efficiency of sewage treatment. Considering that TP standard for the effluent is below 0.1 mg/l in some countries, it should be amended to below 0.1 mg/l in Korea, especially in the watershed of large lakes.2) Urban runoff and combined sewer overflow are not treated, even though their total loading into lakes can be comparable to municipal sewage discharges on dry days. Chemical coagulation and rapid settling might be the solution to urban runoff in regard of intermittent operation on only rainy days.3) Aggregated precipitation in Korea that is concentrated on several episodic heavyrains per year causes a large amount of nonpoint source pollution loading into lakes. It makes the treatment of nonpoint source discharge by methods of other countries of even rain pattern, such as retention pond or artificial wetland, impractical in Korea.4) The application rate of fertilizers in Korea is ten times as high as the average ofOECD countries. The total manure discharge from animal farming is thought to be over the capacity of soil treatment in Korea. Even though large portion of manure is composted for organic fertilizer, a lot of nutrients and organic matter emanates from organic compost. The reduction of application rate and discharge rate of phosphorus from agricultural fields should be encouraged by incentives and regulations.5) There is a lot of vegetable fields with high slopes in the upstream region of the HanRiver. Soil erosion is severe due to high slopes, and fertilizer is discharged in the form of adsorbed phosphorus on clay surface. The reduction of soil erosion in the upland area should be the major preventive policy for eutrophication. Uplands of high slope must be recovered to forest, and eroded gullies should be reformed into grass-buffered natural streams which are wider and resistant to bank erosion.

• 대한환경공학회지
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• 제29권2호
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• pp.197-204
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• 2007

이 연구는 EBPR(enhance biological phosphorus removal)의 혐기조건, 호기/무산소 조건 사이의 상호작용을 알아보고 인의 제거 속도와 인 제거에 미치는 영향인자들을 Batch-test로 조사하였다. 실험결과 무산소단계에서 인의 흡수율은 호기 단계보다 50% 정도 낮았고, 인 방출과 인 흡수의 상관관계는 다른 논문들에 비하여 낮았으며, 계수 b는 높았다. Batch-test의 측정 결과 다른 논문들에 비하여 인 방출과 인 흡수의 상관관계$(R^2=0.557)$는 낮았고 계수b (b=8.4049)는 높았다. 또한, 하수에서 인의 중요한 결합 파트너는 Ca, $Mg^{2+}$, Al, Fe 그리고 $K^+$인데 이 실험 결과 칼륨, 마그네슘 그리고 암모니움은 인과 함께 증감함으로써 인의 방출과 흡수에 밀접한 관계가 있음을 알 수 있었다. 즉, 혐기 단계에서 0.2 mol $K^+Ion$ / mol $PO_4-P$ Ion과 0.21 mol $Mg^{2+}Ion$ / mol $PO_4-P$ ion이 측정되어 인에 대한 칼륨 및 마그네슘의 비율은 1 : 5 정도임을 알 수 있었다.

• 유기물자원화
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• 제11권2호
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• pp.125-131
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• 2003

본 연구는 오수중의 유기물 및 질소 인의 동시제거를 위한 오 폐수 고도처리장치인 간접폭기형 침적생물막여과장치(Indirected Aerated Submerged Biofilter : INSUB)를 개발하기 위하여 실험실적 모형실험을 수행하였다. INSUB에서 오수를 처리함에 있어서, HRT 18시간, 공탑속도 42.5m/hr, 충전율 40%인 경우가 실제로 경제적인 효율을 고려하였을 때, 가장 효율이 좋았다. 각각의 제거효율을 살펴보면, $COD_{cr}$, 90.6%, $COD_{Mn}$ 85.3%, $BOD_5$ 95.0%, T-N 52.3% 그리고 T-P 56.8%로 나타났다. 질소 인의 고효율처리를 위해서는 전탈질공정에 의한 산화질소의 제거를 위해 무산소, 호기조의 조합 등에 의한 system의 일부 다단화가 필요함을 확인할 수 있었다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.77-80
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• 2000

Various analytical methods such as electron microscopy, quinone analysis, and 16S rDNA sequencing studies were used to investigate the microbial communities and to identify the microorganisms responsible for enhanced biological phosphorus removal (EBPR) in an anaerobic/aerobic sequencing batch reactor (SBR) fed with acetate. Electron photomicrographs showed that oval-shaped microorganisms of about $0.7\;{\sim}\;1\;{\mu}m$ in diameter dominated the microbial sludge. These microorganisms contained polyphosphate granules and glycogen inclusions, which suggests that they are a kind of phosphorus accumulating organism. Quinone and 16S rRNA sequence analyses showed that the members of Proteobacteria beta subclass were the most abundant species, which were affiliated with the Rhodocyclus-likes group. Phylogenetic analysis revealed that the two dominating clones of the beta subclass were most distantly related to Propionivibrio dicarboxylicus DSM 5885 and Rhodocyclus tenuis DSM 109 with about 95% and 96% sequence similarity, respectively. Therefore, it was concluded that the oval-shaped organisms related to the Rhodocyclus-likes group are likely to be responsible for biological phosphorus removal in SBR operation supplied with acetate.

• 상하수도학회지
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• 제13권3호
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• pp.29-35
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• 1999

The purpose of this study is to remove the organics, nitrogen and phosphorus using biosorption for the domestic sewage. The new process using biosorption is based on the methods of contact-stabilization, which remove the organics by absorbing them to the surface of the microorganism in the activated sludge. This process consists of biosorption reactor, biosorption clarifier, nitrifying reactor, nitrifying clarifier, denitrifying reactor, phosphorus uptake(polishing) reactor and final clarifier. The efficiency of removal could be reached 91% for organics, 76% for nitrogen, 90% for phosphorus in Eujungbu pilot plant. We operated the plant which irrigated $10m^3$ per day for sewage. During our operation the HRT(Hydraulic Retention time) was maintained for 10.5hr, but it could be reduced as 8.5hr according to our operation results.

• 상하수도학회지
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• 제21권6호
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• pp.745-753
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• 2007

By struvite and hydroxyapatite crystallization, was high concentration of nitrogen and phosphorus in wastewater simultaneously. Particularly, removal of nitrogen and phosphate for crystallization have been applied to landfill leachates and animal wastewater. The purpose of this study is to decide the optimum struvite crystallization factors, sequence of $Mg^{2+}$ addition, pH control and the molar ratio of $Mg^{2+}$ over $PO_4^{3-}$. In conclusion, dosage of the magnesium followed by pH control formed magnesium hydroxide, so pH was decreased. Therefore, pH adjustment should followed by after magnesium dosage and then pH should be adjusted to 11. Over pH 10, it was not good for struvite crystallization efficiency by side reaction. Following of the $Mg^{2+}$ and the $PO_4^{3-}$ are dosed excessively, the removal efficiency of the $NH_4^+$ increased. A molar ratio of $Mg^{2+}:NH_4^+:PO_4^{3-}$, 1.3:1:1.3 was the most on effective for $NH_4^+$ removal at pH 9.5. But for the perfect removal $NH_4^+$, it is thought to be that molar ratio should be 2:1:2.

• 한국환경과학회지
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• 제11권12호
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• pp.1261-1265
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• 2002

This study was focused on the investigation of the characteristics of organics and nitrogen removal with the recycle ratio in anoxic/oxic(A/O) packed bed process that consisted of the anoxic reactor and the aerobic reactor. As increasing the recycle ratio by 0.5, 1.0, 2.0, the COD removal efficiency increased by 94.0%, 98.5%, 98.8% respectively. The aerobic reactor showed the perfect nitrification efficiency by 98.5%, 99.2%, 98.0% respectively. The T-N removal efficiency with the recycle ratio, increased by 56%, 67%, 70% respectively. As increasing the recycle ratio by 0.5, 1.0, 2.0, T-P removal efficiency decreased by 62.1%, 57.4%, 51.3% respectively. The process by releasing the stored phosphorus in the anoxic reactor and uptaking the excess phosphorus in the aerobic reactor, occurred well comparatively when recycle ratio is 0.5. But this process did not occur when the recycle ratio is 1.0 and 2.0. And optimum pH of nitrification was about 6~7 and alkalinity decreased as nitrification rate increased. As increasing the recycle ratio in the anoxic reactor, DO concentration and ORP increased.

• Journal of Electrochemical Science and Technology
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• 제8권2호
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• pp.124-132
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• 2017

The performance of electrolytic processes using copper and catalyzed electrodes for enhanced nutrient removal with various catalyzers and combinations of electrodes was evaluated. The catalyzed electrodes removed more ammonia nitrogen than the copper electrode, but higher ammonia removal was achieved using a Pt/Ti anode. On the other hand, electrolysis using the Pt/Cu anode consumed less energy and cost less. During electroreduction, nitrate was better removed by a pair of copper electrodes than by the catalyzed electrodes. During electrolysis of synthetic wastewater, ammonia removal not only increased owing to direct oxidation at the anode, but was also influenced by indirect oxidation at the cathode. Platinum-coated copper and titanium cathodes actively produced oxidizers and thus removed more ammonia than a pure metal cathode. Although phosphorus was removable irrespective of the type of catalyzer, electrocoagulation using the copper electrode achieved complete removal of phosphorus in a period of less than 10 min.

• 한국물환경학회지
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• 제31권4호
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• pp.418-427
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• 2015

This study was carried out to evaluate the performance of a lab-scale novel septic tank system for improving the conventional septic tank in the developing countries of water shortages. The lab-scale novel septic tank system consists of sepetic tank, aeration tank with HBC-ring, and sand filter. Optimum HRT was reguired about 1.5days to get a total COD removal efficiency of 90%, COD, BOD and SS removal efficiency was about 70%, 60%, and 85% in sepetic tank only. The structure of sepetic tank with two stages results in the high removal efficiency of organic matter. When sepetic tank, aeration tank, and sand filter were more than HRT 1.5days, 18hrs, and 12hrs, respectively, final effluent was less than 20 mg/L of BOD, 14 mg/L of SS, so that there is a high potential of its use for reusing water in flush toilet. There is no significant effect of HRT change on nutrient removal. Total nitrogen removal efficiency was about 40%, final effluent was 30~40 mg/L of TN, total phosphorus removal efficiency was about 11~25%, final effluent was 9~12 mg/L of TP. Because there is very small amounts of organic nitrogen and phosphorus in effluent, it was possible to reuse water for agricultural use.

• 한국환경농학회지
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• 제37권1호
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• pp.66-72
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• 2018

본 연구는 하수처리를 위한 VF-HF 조합형 인공습지에서 굴패각이 인공습지 수명에 미치는 영향을 조사하기 위해, 6년간 인공습지에서 총인의 농도 변화를 장기간 모니터링 한 후 이를 토대로 굴패각이 인공습지의 수명 연장에 미치는 영향을 종합적으로 평가하였다. 왕사만 사용한 system A에서 인이 실제 포화에 도달하는 시간은 최대 인 흡착능력에 기반한 이론적 포화치에 비해 4배 이상 긴 것으로 평가되었으며, 특히 인의 포화패턴은 운영 초기에는 일정농도 수준으로 유지되다가 흡착에서 파과점과 같은 지점을 통과하면서 서서히 포화가 진행되어가면서 최종적으로 포화에 도달하였다. 굴패각과 왕사를 혼합한 여재를 사용한 system B에서도 이론적 포화예상시간을 초과하여 안정적으로 인이 처리됨을 확인하였고, 굴패각의 첨가로 system A에 비해 인의 포화시기가 연장됨을 확인하였다. 이상의 결과를 미루어 볼 때 실제 인공습지 여재에 굴패각을 혼합하면 여재의 인 흡착량을 증가시켜 이론적인 포화치보다 인의 포화시기를 더 늘릴 수 있으며, 최종적으로 인공습지의 수명을 연장 시킬 수 있다고 판단된다. 또한 굴패각을 사용하는 것은 굴 양식장에서 발생하는 부산물인 굴패각을 재활용하는 것으로서 폐기물의 재활용 측면에서 환경오염을 줄이기 위한 방안으로도 활용될 수 있을 것이다.