• 산업기술연구
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• 제31권A호
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• pp.135-145
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• 2011

This study was conducted to analyze the cost effectiveness in line with total phosphorus standard enforcement of public sewage treatment facilities. The additional cost for the total phosphorus removal process was calculated to analyze the cost effectiveness of the advanced water purification process. The analysis results showed that the T-P removal by coagulation sedimentation was more efficient than the advanced water purification facilities in terms of facilities investment cost, and if the coagulation filteration was used for T-P removal, the activated carbon process among the advanced water purification techniques was more efficient in terms of facilities investment cost. In this study, the effects of the T-P removal process that will be additionally introduced according to the tightening of the effluent T-P standard were analyzed within a limit. The actual benefits of improved T-P concentration in the water source will provide diverse values, including the leisure water, environment improvement water, eco-system in the water source and industrial water, in addition to the advanced water purification.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.315-320
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• 2006

There have been several problems in treating shipboard sewage due to special environmental conditions of ship, such as limited space, rolling and pitching, change of temperature and so on. It was suggested that Sequence Batch Reactor (SBR) might be suitable process for overcome these problems in terms of small size, high capacity of treating wastewater and full automation. In this study a SBR process was employed for biological treatment of organic wastes in the shipboard sewage. This process was able to remove nitrogen and phosphorus as well as organic matter efficiently. More than 95% of chemical oxygen demand(COD) were removed. In addition, about 97% of total nitrogen (T-N) was reduced. The total phosphorus(T-P) reduction averaged 93%. A disturbance operation caused by the treatment of Methylene Blue Active Substances(MBAS) was not observed.

• 한국환경보건학회지
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• 제35권3호
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• pp.214-219
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• 2009

This study examined the removal efficiency of the nitrogen and phosphorus in order to compensate for the combined process of ATAD(Autothermal Thermophilic Aaerobic Digestion) and EGSB(Expended Granular Sludge Bed), which are treatment methods for livestock wastewater, by introducing SBR(Sequencing Batch Reactor) as post-treatment process. The analysis on the treatment efficiency of each operation mode showed that, in the case of T-N, the treatment efficiency were 67.1% and 74.2% for Run-1 and Run-2, respectively, and in the case of T-P, the values were 71.2 and 74.1, respectively, which are indicating that the treatment efficacy is higher in the condition of Run-1, in which the time period of Anoxic and Aerobic segments were increased. In addition, the result of analyzing removal characteristics of nitrogen and phosphorus by Influx load showed that removal efficiency of nitrogen was better in the case of high influx load than in the case of low influx load. Regardless of Influx load, phosphorus showed constant influx concentration, so that removal efficiency of phosphorus was influenced littler by Influx load than that of nitrogen. This study also fed methanol as an external carbon source and performed experiment to induce denitrification under anoxic condition by using nitrate among nitrogen compounds of SBR reactor, and the results showed that intermittent feeding was more effective in Nitrogen Removal than composite feeding.

• 대한환경공학회지
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• 제39권1호
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• pp.40-49
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• 2017

본 연구에서는 경기도 고양시 소재 I 수질복원센터의 공정별 유량과 총인(TP) 농도를 활용하여 2015년도 기준 TP 물질수지도를 작성하고, 이를 분석하여 하수처리시설에서 인(P)을 회수할 수 있는 최적의 단위공정을 실증적으로 선정하고자 하였다. 인 회수공정의 도입 가능성을 평가하기 위하여 유량, TP농도, TP부하량 및 SS에 대한 정량적 지표를 제안하는 한편, 이를 I 수질복원센터에 적용하였다. 또한 I 수질복원센터의 탈수여액을 대상으로 인 회수공정의 도입 가능성에 대한 기초실험을 실시하였다. TP 물질수지를 분석한 결과, 하수처리장 유입수에 비해 유량은 1/16로 적지만 TP농도는 약 78배, TP부하량은 4.8배에 달하는 반류수 계통을 대상으로 인을 회수하는 것이 하수처리시설 전체의 TP부하를 저감하는데 유효한 것으로 나타났다. 반류수 계통의 단위공정들을 대상으로 본 연구에서 제안한 정량적 지표를 활용하여 인 회수공정의 도입 가능성을 상세히 평가한 결과, (잉여농축조 상징액+잉여저류조 월류수) 또는 탈수여액이 적합한 것으로 나타났다. 한편, TP농도가 141.5 mg/L에 달하는 탈수여액을 대상으로 결정화에 의한 인 회수 기초실험을 실시하였다. 탈수여액의 pH를 10으로 조정한 후 칼슘이온($Ca^{2+}$)을 각각 250, 500, 1000 mg/L씩 주입하여 완속교반을 실시하였다. 기초실험 결과 탈수여액 중의 $PO_4-P$ 및 TP를 95% 이상 제거할 수 있는 것으로 나타나 인 회수공정의 도입 가능성이 확인되었다.

• Corrosion Science and Technology
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• 제19권1호
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• pp.31-36
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• 2020

An efficient wet process approach to modifying natural graphite (NG) electrodes for Li-ion batteries is introduced in this paper. With homogeneous mixing and thermal decomposition of NG with diammonium phosphate ((NH₄)₂HPO₄), phosphorus and nitrogen were successfully incorporated into the surface layer of NG particles. Electron microscopy and X-ray photoelectron spectroscopy analyses demonstrated that the surface was well modified by this process. As a result, the treated NG electrodes exhibited much improved electrochemical performance over pristine NG at two different temperatures: 25 ℃ and 50 ℃. Excellent capacity retention of 95.6% was obtained after 100 cycles at 50 ℃. These enhanced properties were confirmed in a morphology analysis on the cross-sections of the NG electrodes after galvanostatic cycling. The improved cycle and thermal stabilities can be attributed to the surface treatment with phosphorus and nitrogen; the treatment formed a stable solid electrolyte interphase layer that performed well when undergoing Li insertion and extraction cycling.

• 수산해양기술연구
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• 제52권3호
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• pp.271-275
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• 2016

Recently, pollution problem in coastal water has become more serious and pollution including red tide serves as a main reason for reduction of fishes resources. Particularly, nutrients such as nitrogen and phosphorus are the most serious pollutants. Normally, biological wastewater treatment process is used in removing such nutrients. However, it is difficult to adopt the biological wastewater treatment process to a small-scale fish processing factory in case of using seawater as wash water. Thus, removing nutrients through struvite crystallization is investigated in this study for treating shrimp processing wastewater. Experiments were conducted by varying molar ratio of $Mg^{2+}:NH^4-N:PO^4-P$ from 1:1:1 to 2:1:1. It can be concluded that optimum molar ratio is 1:1:1. Struvite crystallization process is compared with chemical coagulation process using PAC and struvite crystallization process is proven as the more effective process in removing nutrients from wastewater. In view of results obtained from these experiments, struvite crystallization process is a promising method in removing nitrogen and phosphorus from wastewater; however, not so good in removing organics. Thus, struvite crystallization process is suitable as the pre-treatment process in treating shrimp processing wastewater and additional biological process is needed to remove organics.

• 상하수도학회지
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• 제32권1호
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• pp.47-53
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• 2018

This study investigated phosphorus removal from secondary treated effluent using coagulation-membrane separation hybrid treatment to satisfy strict regulation in wastewater treatment. The membrane separation process was used to remove suspended phosphorus particles after coagulation/settlement. Membrane separation with $0.2{\mu}m$ pore size of micro filtration membrane could reduce phosphorus concentration to 0.02 mg P/L after coagulation with 1 mg Al/L dose of polyaluminum chloride (PACl). Regardless of coagulant, the residual concentration of phosphorus decreased as the dose increased from 1.5 to 3.5 mg Al/L, while the target concentration of 0.05 mg P/L or less was achieved at 2.5 mg Al/L for the aluminum sulfate (Alum) and 3.5 mg Al/L for PACl. Moreover, alum showed better membrane flux as make bigger particles than PACl. Alum showed a 40% of flux decrease at 2.5 mg Al/L dose, while PACl indicated a 50% decrease of membrane flux even with a higher dose of 3.5 mg Al/L. Thus, alum was more effective coagulant than PACl considering phosphorus removal and membrane flux as well as its dose. Consequently, the coagulation-membrane separation hybrid treatment could be mitigate regulation on phosphorus removal as unsettleable phosphorus particles were effectively removed by membrane after coagulation.

• 상하수도학회지
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• 제26권3호
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• pp.443-451
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• 2012

Wastewater treatment plants need to reduce phosphorus in order to meet increasingly stringent regulations on phosphorus. This study evaluated the feasibility of dolomite as a coagulation aid to enhance phosphorus removal from secondary treated wastewater by chemical coagulation. Standard jar tests were conducted to evaluate the effect of dolomite addition on a coagulation process for phosphorus removal and to determine the optimum doses of coagulants and dolomite. Coagulants used with dolomite yielded a significant improvement in phosphorus removal and reduced total phosphorus concentrations below 0.02 mg/L in wastewater effluent. Dolomite has played an important role in enhancing phosphate adsorption and increasing pH, as a coagulation aid. The maximum removal efficiency of phosphorus in this study was yielded at 25 mg/l of dolomite and 20 mg Al/L of PAC dose. However, considering economic aspects, the optimum doses of dolomite and PAC were 10 mg/L and 15mg Al/L, respectively. Consequently, dolomite, a coagulation aid, can be used in coagulation processes to enhance the removal of phosphorus.

• 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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• 제26권5호
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• pp.713-721
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• 2012

강이나 호수로 유입되는 인(P)이 종종 부영양화의 가장 큰 제한요소로 작용한다. 그런데 하수처리장의 방류수가 자연수계에 인의 중요한 공급처로 작용하는 경우가 많기 때문에 하수처리장의 최종 처리수에서 인의 제거가 요구된다. 하수에서 인을 제거할 수 있는 많은 기술 중에서, 활성 칼슘-황토의 복합체를 이용한 흡착기술을 연구하였다. 칼슘을 황토에 첨가하여 인의 흡착 용량과 흡착강도를 증가시켰다. 칼슘을 첨가한 황토를 최적 온도로 밝혀진 $400^{\circ}C$의 고온에서 활성화시켰다. $400^{\circ}C$ 미만에서 활성화시킨 칼슘-황토는 하수처리 공정의 활성칼슘-황토 복합체를 이용한 처리조에 적용하기엔 강도가 부족하였다. 반면 $400^{\circ}C$ 초과 온도에서 활성화시킨 칼슘-황토 복합체는 복합체 표면이 유리화되어 흡착용량이 감소하였다. 활성칼슘-황토 복합체는 표면에 충분한 기공이 발달하지 못하여 인의 흡착용량에 한계는 있으나 칼슘을 첨가하였기 때문에 흡착강도는 높았다. 활성칼슘-황토는 입자형 복합체로 만들어졌다. 제조된 복합체를 흡착칼럼에 채워 하수처리공정에 적용하였다. 활성칼슘-황토의 복합체를 충진한 칼럼을 파일롯트 플랜트에 적용한 결과 0.5 mg/l의 인의 농도를 0.1 mg/l로 낮출 수 있었고, 이온성 인을 4개월의 운전기간 동안 완전하게 흡착시켜 제거할 수 있었다.