• KSBB Journal
• /
• 제13권6호
• /
• pp.638-643
• /
• 1998

An investigation was made to develop new biofilm medium which could be applied to the Sequencing Batch Biofilm Reactor(SBBR) system for enhanced nutrient removal. 21 kinds of polyurethane media were tested fro adhesion ability for nitrifying bacteria. Nitrification rates were also tested by introducing synthetic wastewater containing ammonium-nitrogen to reactors with biofilm media. It was found that Z96-06 medium had higher selective adhension ability for nitrifying bacteria than the other biofilm media. The nitrification rate was 2.21 mg {{{{ { NH}`_{4 } ^{ +} }}}}-N /L$.$h$.$g MLSS when we operated the SBBR system containing Z96-06. Nitrification rate of the SBBR system increased approximately by 30% compared with that of the Sequencing Batch Reactor(SBR) system which did not contain biological carrier.

• 한국조경학회지
• /
• 제40권1호
• /
• pp.100-109
• /
• 2012

하천수를 정화하는 자유수면인공습지의 정수식물 성장기(4~9월)와 비성장기(1~3월과 10~12월)의 $PO_4-P$와 TP제거율을 비교 연구하였다. 실험 습지 시스템은 광주광역시를 흐르는 광주천 중류 고수부지에 2008년 조성되었으며, 길이 46m, 폭 5m 규모이다. 2008년 포트에서 2년 자란 부들(Typha angustifloria L.)과 줄(Zizania latifolia Turcz)을 시스템의 1/2씩 각각 식재하였다. 광주천의 물이 자연유하로 시스템에 유입되며, 처리수는 광주천으로 방류된다. 유입수의 양과 수심은 밸브와 위어(weir)로 조절할 수 있다. 유입수 및 유출수의 인 농도를 2010년 1월부터 12월까지 7~10일 간격으로 조사 분석하였다. 하루에 약 $710m^3$의 하천수가 시스템으로 유입되어, 체류시간은 약 1.5hr이었다. 조사기간 유입수와 유출수의 $PO_4-P$ 평균농도는 각각 0.144, 0.105mg/L이었으며, $PO_4-P$ 평균제거율은 28.1%였다. 유입수와 유출수의 TP평균농도는 각각 0.144, 0.105mg/L이었으며, TP 평균제거율은 20.7%를 보였다. t 검정결과, 정수식물 성장기의 $PO_4-P$ 제거율(31.448)이 비성장기 $PO_4-P$ 제거율(25.829)보다 높았으며(p<0.001), 정수식물 성장기의 TP 제거율(27.230)도 비성장기의 TP 제거율(14.856)보다 높게(p<0.001) 나타났다. 인공습지에서 인 제거는 잔재물-토양 층의 흡착, 입자성 인과 Ca, Fe, Al과 결합된 인산염의 침전, 그리고 정수식물의 흡수가 중요하다. 정수식물 성장기가 비성장기보다 $PO_4-P$와 TP의 제거율이 상대적으로 높은 원인은 흡착과 침전에 의한 인 제거는 계절에 관계없이 일어나나, 정수식물의 흡수는 성수식물 성장기에만 일어나기 때문이다.

• 한국물환경학회지
• /
• 제20권5호
• /
• pp.437-446
• /
• 2004

To develop sewage treatment apparatus by natural purification method, the sewage treatment plant that consisted of aerobic and anaerobic plot was constructed. And then, the effects of treatment conditions on the removal of pollutants in the relation to sewage loading, sewage injection method and season according to the pebble kind. Removal rate of BOD and COD according to the sewage loading in effluent were over 95 and 77%, respectively. Removal rate of nitrogen in treated water by aerobic plot and effluent using sand were about 22~40 and 49~75%, respectively. Those of effluent using sand 75%+ oyster shell 25% and sand 50%+ oyster shell 50% as filter media in comparison with using sand were about 7~25 and 16~23%, respectively. Removal rate of phosphorus in treated water by aerobic plot and effluent using sand as filter media were about 30~36 and 52~56%, respectively. Those of effluent using sand 75%+ oyster shell 25% and sand 50%+ oyster shell 50% in comparison with using sand as filter media were about 11~40 and 12~45%, respectively. Removal efficiency of BOD and COD according to the intermittent injection method of sewage were slightly decreased, but those of nitrogen and phosphorus were little varied in comparison with continuous injection method. Removal efficiency of BOD and COD in winter in comparison with the others were little varied, but those of nitrogen and phosphorus slightly decreased.

• 한국물환경학회지
• /
• 제31권2호
• /
• pp.94-102
• /
• 2015

Electro-coagulation experiments were conducted with aluminum (Al) or iron (Fe) electrode in order to determine the optimal electrode material and operation conditions for algae removal. Al electrode showed higher removal rate of algae than Fe electrode because Al flocs have positive surface charges which electrostatically attract algae species having negative surface charges. Removal rate of algae and total phosphorous (T-P) was increased as current density and electrode area increases. It was also found that initial pH with neutral range was optimum for T-P removal by electro-coagulation. Bench-scale continuous flow experiments consisted of electro-coagulation reactor, agitation tank and settling tank were conducted. In electro-coagulation reactor, a large fraction of Al flocs were distributed to scum layer, due to the gas bubbles generated by electrolysis reaction. In agitation tank, most of Al flocs were settled and the optimal mixing intensity was found to be 50 rpm to achieve good settleability. The removal rate of algae was about 90-95%. Additionally, the removal rate of the T-P and COD was observed to be $73.8{\pm}8.0%$ and $75.0{\pm}3.8%$, respectively. Meanwhile, the removal rate of total nitrogen (T-N) was relatively low at only 24%.

• Environmental Engineering Research
• /
• 제13권3호
• /
• pp.155-161
• /
• 2008

This study examined effects of the fermented leachate of food waste (FLFW) on nitrogen and phosphorous removal for domestic wastewater containing a low carbon-to-nitrogen (C/N) ratio in sequencing batch reactor (SBR). When the FLFW was not supplied in the process, release of phosphorus and excessive intake was not observed at both anaerobic and aerobic stages. On the other hand, when the FLFW was gradually added, active release of phosphorus and intake of phosphorus was noticed at an anaerobic stage and aerobic stage, respectively, resulting in improved phosphorus removal efficiency. The removal efficiency of nitrogen and phosphorus was increased from 75% and 37% (R-1, control test) to 97% and 80% (R-4, the highest substrate ratio test), respectively. In addition, although activity of the nitrogen oxidizing microorganisms was reduced when the reaction temperature was decreased to $10^{\circ}C$, the phosphorus removal efficiency was shown to increase with the addition of FLFW, indicating an independence from temperature. Overall, this study suggests that an efficient nutrients removal process can be successfully employed into a SBR when the FLFW is added to a wastewater which has a low C/N ratio.

• 대한환경공학회지
• /
• 제31권8호
• /
• pp.673-678
• /
• 2009

2011년부터 시행될 2단계 수질 오염 총량제에 대비하여 고효율 인 제거 공정 개발이 필요하며 본 연구에서는 생물학적 처리와 화학적 응집처리를 조합한 공정이 대안으로 검토되었다. 2세대 응집제로서 최근 많이 사용되고 있는 PAC(poly aluminum chloride)를 이용하고 실제 하수종말처리장 A2O 공정의 호기조 유출수를 시료로 하여 인 응집 특성 및 적정 조건, 효율 향상 방안 등에 대해 실험연구를 수행하였다. 먼저 적정 PAC 투입 농도는 부피기준으로 30 ppm, mol비로는 2.81 mol Al/mol P인 것으로 나타났다. 단순침전에서 17.2%에 불과하던 용존성 인의 제거율이 PAC 10 ppm 투입으로 30.3%까지 증가하였으며, 20 ppm에서 30 ppm으로 PAC 투입량을 증가시킬 때 49.3%에서 88.4%로 제거율을 크게 향상시킬 수 있었다. 이때 총 인의 제거율은 92.4%, 유출수 총 인 농도는 0.3 mg/L로 총량제에 부합하는 방류수 수질을 달성할 수 있었다. 적정한 응집시간은 4분, 침전시간은 20분, 초기 pH는 7로 나타났고 원시료 (pH 7.0)는 별도의 pH 조절 없이 응집 가능한 것으로 판단되었다. pH 7 조건에서 용존성 인의 제거가 크게 향상되었으며, 추가적인 확인 연구가 필요하나, 이는 인의 경우 $Al(OH)_3$에 의한 sweep floc formation이 주요 제거 기작임을 의미하였다. 2차침전조 유입부에 PAC를 투입하여 2차침전조를 응집침전조로 활용하는 방안과 별도의 응집침전조를 2차침전조 후단에 설치하여 PAC를 투입하는 방안을 비교한 결과 PAC 투입량 대비 인 제거효율 증진 관점에서 후자가 바람직한 것으로 조사되었다. 이때 처리수의 인 농도는 0.18 mg/L, 제거율은 95.4%로 향상시킬 수 있었다. 끝으로 응집 처리수를 반송할 경우 인 제거 효율을 높일 수 있었으며 적정 반송율은 0.3인 것으로 분석되었다.

• 환경영향평가
• /
• 제5권2호
• /
• pp.21-31
• /
• 1996

To assess the impact resulted from the slag dumping, we studied that the changes in the concentration of heavy metal were researched through the statistic analysis at 4 stations in Yongil bay, Korea from 1988 to 1995. And in order to clarify resulting from the changes in heavy metal concentration due to be leaked out from dumped slag, it was fulfilled experiments of the slag extraction. In the extracting experiment, Pb and As were only leaked out from slag aged during 10 days but all of heavy metals were not from it aged during 90 or 180 days. It was found that the concentrations of heavy metals in sea water of vincinity of slag dumping area were still remained in similar, comparing with it of control site(site 4) when they were by analysed statistic method, anova test and Mann-Whitney test. The slag recycling ratio of our country is lower than foreign country. While we need to apply a new process for phosphate treatment, foreign country already apply a slag to phosphorous removal. We suggest that slag dumping cannot putatively affected the changes in the concentration of heavy metal. And we thought that impact of heavy metal induced by slag dumping was not severe. So, it is necessary to utilize this process in phosphorous removal, like a foreign country.

• 한국수처리학회지
• /
• 제26권6호
• /
• pp.53-59
• /
• 2018

Water pollution is drastically increasing day by day, because of the enhancement in use of livestock, urban sewage detergents and fertilizers. Moreover increase in concentration of phosphorous and nitrogen contained in sewage, leads to green tide problem in the rivers and causes marine pollution. For this problem to solve, several technologies are being researched and developed. Among them, this experiment is a study on Bench-scale STP based on internationally certified sewage treatment equipment by MEPC. 227(64) of IMO. The purpose of this study is to compare the biological treatment efficiency of phosphorus of Bench-scale STP. The ratio of C : N : P was set to 10 : 5 : 3 and 10 : 3 : 1 as the operating conditions. And the operation cycle was set to anoxic(mixed) 70 min - aeration 50 min (70-50), anoxic(mixed) 90 min - aeration 60 min (90-60). As a result, the phosphorous treatment efficiency was 88% at average, and the treatment efficiency was steady at 90-60 better than 70-50. The efficiency of the bench-scale STP has been verified through this experiment and additional experiments are required to derive the optimal operating conditions.

• 한국산학기술학회논문지
• /
• 제13권2호
• /
• pp.941-946
• /
• 2012

수생식물은 폐수정화에 있어서 중요한 역할을 한다. 수생식물은 뿌리로 영양물질을 흡수해 수질개선을 할 수 있는 능력을 가지고 있다. 본 연구에서는 실험실에서 수생식물인 물상추, 자라풀, 생이가래를 각각의 수조와 혼합한 수조에서 영양물질 제거뿐만 아니라 유기물에 관해 관찰하였다. 단일수조에서 가장 많이 제거된 총 질소는 물상추가 86.47%이고, 생이가래와 물상추가 혼합 식재된 수조가 76.11%로 관찰되었다. 총인의 경우 단일수조에서 가장 많이 제거된 것은 물상추가 75.60%이고, 생이가래와 물상추가 식재된 수조가 71.11%로 관찰되었다. 암모니아제거의 경우도 두 개의 수조에서 유사한 결과가 나타났다. 또한 물상추 식재된 단일수조가 유기물이 가장 많은 68.46%로 제거를 보였다. 반면 혼합수조에서는 유기물의 제거가 생이가래와 물상추가 식재된 수조가 가장 많은 82.73%로 나타났다.

• 한국환경보건학회지
• /
• 제23권1호
• /
• pp.34-42
• /
• 1997

A laboratory experiments were performed to investigate the treatment of photographic processing wastewater by chemical oxidation and biological treatment system. The effect of reaction conditions such as hydrogen peroxide dosage, ferrous sulfate dosage and pH on the COD removal in Fenton oxidation were investigated. The optimal dosage of hydrogen peroxide was 2.58 M and 3.87 M for the developing and fixing process wastewater, respectively. The Fenton oxidation was most efficient in the pH range of 3-5 and the optimal condition for initial reaction pH was 5 for a developing process wastewater. With iron powder catalyst, the COD for a developing process wastewater was removed in lower pH than with ferrous sulfate catalyst. The removal efficiency of COD for refractory compounds such as Diethyleneglycol, Benzylalcohol, Hydroxylamine Sulfate, Ammonium Thiosulfate, Ammonium Ferric EDTA and Disodium EDTA in the photogaphic wastewater was found than 90% except Potassium Carbonate. When the photographic processing wastewater after pretreatment by Fenton oxidation was treated with batch activated sludge process, the addition of $KH_2PO_4$ as a phosphorous compound improved the removal efficiency of COD. During the continuous biological treatment of developing and fixing process wastewater after pretreatment by Fenton oxidation, the effluent COD concentration less than 100 mg/l was obtained at 0.425 and 0.25 kgCOD/m$^3$.d, respectively.