In this research, characteristics of nitrification and denitrification using the microorganism attached on sponge and plates were examined. The denitrification and nitrification performance were investigated under the anaerobic and aerobic condition for about 2 months. Because the basins of denitrification and nitrification were connected in series, wastewater was flowed from denitrification basin to nitrification one. The 90% of influent flowrate was returned from nitrification basin to denitrification one. Most of organic material was removed in nitrification basin, wherease the only exact amount of organics required in denitrification process was removed in denitrification one. This experiment resulted in that heterotrophic bacteria existing in aerobic basin governed the removal efficiency of organic compounds. In case the influent BOD concentration into nitrification basin was 80mg/l, it did not affect to accumulation of nitrifying bacteria, the balance of heterotrophic bacteria was proved to be an important factor in nitrification/denitrification method such as anaerobic and aerobic cycling type.

인과 질소는 하천, 호소 등의 부영양화의 주요 인자로 작용하고 있고 특히 하수 중의 인 농도가 1 mg/L 이상일 경우 조류의 급증식이 일어날 수 있다. 현재 우리나라 하수처리 공정은 인을 기준치 이하로 제거하기 위해 총인 처리 공정을 운영하고 있으나, 이 과정에서 제거된 인은 슬러지와 혼합되어 폐기처분되고 있다. 인은 무한자원이 아닌 유한자원으로 비료, 금속표면처리 세정제를 비롯하여 다양한 용도로 사용될 수 있으며, 우리나라의 경우 전량 수입에 의존하고 있다. 최근 인광석 매장량의 한계로 인하여 인을 회수하여 재이용하는 기술이 반드시 필요한 실정이고, 그 대안으로 축산폐수, 혐기성발효액, 하수처리 시 발생되는 인을 유용한 자원으로 회수하는 방법에 관한 연구가 활발히 이루어지고 있다. 그러나 기존의 연구된 인결정은 100㎛ 이하의 미세 결정으로 고액분리 및 탈수에 어려움이 있다. 본 연구에서는 인제거 기술 중 화학적 침전법 중 하나인 MAP(Magnesium Ammonium Phosphate) 법을 적용하여 부천시와 공동으로 부천시 소재 공공하수처리장에서 발생되는 탈수여액내의 인을 회수하고자 하였으며 다양한 실험조건(pH, 약품, 주입량, Seed적용)에 따라 인회수 및 입상화의 최적 조건을 도출하고 연속반응조를 통하여 2mm 이상의 크기로 입상화가 가능함을 확인하였다. Jar-test 실험결과 pH 9, 몰비 1~9(Mg2+/PO4-P) 범위에서 PO4-P가 55%~90% 제거되었으며, 생성된 결정화물을 seed로 사용하여 최적 약품투입량 도출결과 pH9, 몰비1 조건에서 6회 재사용시 seed 미적용 대비 PO4-P 제거율이 36% 상승하였다. 도출된 조건을 이용하여 2단 상향류(내경이 1.1cm, 1.8cm) 반응조와 침전조로 구성된 Lab Scale 반응조에서 선속도를 변화시켜 입상화를 유도하였다. 입상화시 PO4-P 제거율은 70%~84%, NH3-N 제거율은 20%~28%로 나타났으며, 내경 1.1cm의 반응조 하부에는 2mm~1.5mm, 내경 1.8cm의 반응조 상부에서는 0.6mm~1.2mm로 입상화되었다. 본 연구에서 미립 결정화물을 연속 순환을 통하여 선속도에 따른 입상화를 확인한 결과, 2mm 이상의 인 결정화물의 생성이 가능함을 입증하였다. 이를 통해 탈수 및 건조에 소요되는 에너지를 최소화하고 고순도 입상화로 비료 가치를 향상시켜 경제성 확보가 가능할 것으로 사료된다.

Combined oral contraceptives (OCs) are a common method of contraception; however, they are associated with a twofold to sixfold increased risk of venous thrombosis (VT). The association between estrogen-containing OCs and VT is well established. After the first generation progestogens, new progestogens were developed. However, the risk of VT is higher for users of OCs with third generation progestogens than for those using second generation progestogens. We experienced a patient, a 25-year-old young woman with chest pain after taking third generation OCs. We performed chest computed tomography (CT) and lower extremity venogram CT. She was diagnosed with a pulmonary thromboembolism and deep vein thrombosis. She was treated with low molecular weight heparin and warfarin for six months. We report on this case with a review of the relevant literature.

Drug-eluting stents (DES) have reduced the rate of restenosis and the need for repeated revascularization of target lesions. However, in stent restenosis is still a major issue and very late stent thrombosis seems to occur more frequently with DES. Recently, incidence of stent thrombosis as a fatal complication has increased and dual antiplatelet therapy is recommended for at least 12 months after implantation. Here we report on a case of ST-segment elevation myocardial infarction due to total occlusion caused by very late stent thrombosis and in stent restenosis simultaneously at 42 months after DES implanta-tion.

We report on the case of a 59-year-old man who presented with continuous chest discomfort. The patient's initial electrocardiogram (ECG) showed normal sinus rhythm. Coronary angiography showed significant stenosis in the proximal left anterior descending coronary artery (LAD), the distal left circumflex coronary artery (LCX). Therefore, we deployed a stent in the proximal LAD and the distal LCX. Two days after percutaneous coronary intervention (PCI), he complained of atypical chest pain. His ECG showed ST segment elevation in leads V1 to V3. In emergent coronary angiography, there was no stent thrombosis. ECG findings showed that the ST segment has a "saddle back" ST-T wave configuration in which the elevated ST segment descends toward the baseline, then rises again to an upright T wave, like the Brugada ECG pattern. This case report shows how dynamic ST segment elevations may look similar in cases of stent thrombosis after PCI.