This study evaluates the potential of various coagulants to enhance the efficiency of total phosphorus removal facilities in a sewage treatment plant. After analyzing the existing water quality conditions of the sewage treatment plant, the coagulant of poly aluminium chloride was experimentally applied to measure its effectiveness. In this process, the use of poly aluminium chloride and polymers in various ratios was explored to identify the optimal combination of coagulants. The experimental results showed that the a coagulants combination demonstrated higher treatment efficiency compared to exclusive use of large amounts of poly aluminium chloride methods. Particularly, the appropriate combination of poly aluminium chloride and polymers played a significant role. The optimal coagulant combination derived from the experiments was applied in a micro flotation method of real sewage treatment plant to evaluate its effectiveness. This study presents a new methodology that can contribute to enhancing the efficiency of sewage treatment processes and reducing environmental pollution. This research is expected to make an important contribution to improving to phosphorus remove efficiency of similar wastewater treatment plant and reducing the ecological impact from using coagulants in the future.

This study explored effects of a sludge-based biochar addition on nitrogen removal of membrane bioreactor (MBR) for wastewater treatment. The membrane fouling reduction by the biochar addition was also investigated. A dose of 3 g/L of the biochar was applied to an MBR (i.e., BC-MBR) and treatment efficiencies of organic matter and nutrient were analyzed. The MBRs with powdered activated carbon (i.e., AC-MBR) and without any additives were also operated in parallel. The average removals of COD and TN were improved with the biochar addition compared to those with the control MBR. Interestingly, operational duration was also increased with biochar addition. The CLSM analysis revealed that biomass amounts of BC-MBR and AC-MBR were reduced by more than 40%, and thickness of the biofilm attached to the membrane surface also was decreased. The physical properties of biochar surfaces were compared with a commercial powdered activated carbon. The specific surface area with 38 m2/g and pore volume with 0.13 cm3/g of the biochar were much smaller than those of the powdered activated carbon, which were 1100 m2/g and 0.67 cm3/g, respectively. Manufacturing conditions for the biochar production needs to be further investigated for enhancing physical properties for adsorption and biological improvement.

The object of this study is to feasibility assesment for co-digestion efficiency of food waste recycling wastewater(FWR) with thermal hydrolysis process dehydration cake (THP Sludge). As a result of THP pre-treatment experimental conditions to 160oC and 30 minutes, the solubility rate(conversion rate of TCOD to SCOD) of the THP sludge increased by 34%. And the bio-methane potential in the THP sludge increased by about 1.42 times from 0.230 to 0.328 m3 CH4/kg VS compared to the non-pre-treatment. The substrates of the co-digestion reactor were FWR and THP sludge at a 1:1 ratio. Whereas, only FWR was used as a substrate in the digestion reactor as a control group. The experimental conditions are 28.5 days of hydraulic retention time(HRT) and 3.5 kg VS/m3-day of organic loading rate(OLR). During the 120 days operation period, the co-digestion reactor was able to operate stably in terms of water quality and methane production, but the FWR digestion reactor deteriorated after 90 days, and methane production decreased to 0.233 m3 CH4/kg VS, which is 67% of normal condition. After 120 days of the experiment, organic loading rate(OLR) of co-digestion reactor was gradually increased to 4.5 kg VS/m3-day and operated for 80 days. Methane production during 80 days was evaluated to be good at the level of 0.349 m3 CH4/kg VS. As a result of evaluating the dehydration efficiency of the sludge before/after 150-180oC THP using a filter press, it was confirmed that the moisture content of the sludge treated before THP at 180oC was 75% and improved by 8% from 83-85% level. Therefore, it is expected that the co-digestion reactor of FWR and THP sludge will ensure stable treatment water quality and increase bio-methane production and reduction effect of dehydration sludge volume.

Indirect oxidation using chlorine species oxidizing agents is often effective in wastewater treatment using an electrochemical oxidation process. When chlorine ions are contained in the wastewater, oxidizing agents of various chlorine species are produced during electrolysis. In a ballast water management system, it is also used to treat ballast water by electrolyzing seawater to produce a chlorine species oxidizer. However, ballast water in the brackish zone and some wastewater has a low chlorine ion concentration. Therefore, it is necessary to study the chlorine generation current efficiency at various chlorine concentration conditions. In this study, the chlorine generating current efficiency of a boron-doped diamond(BDD) electrode and insoluble electrodes are compared with various chloride ion concentrations. The results of this study show that the current efficiency of the BDD electrode is better than that of the insoluble electrodes. The chlorine generation current efficiency is better in the order of BDD, MMO(mixed metal oxide), Ti/RuO2, and Ti/IrO2 electrodes. In particular, when the concentration of sodium chloride is 10 g/L or less, the current efficiency of the BDD electrode is excellent.

본 연구는 비용매 상분리법(nonsolvent induced phase separation, NIPS)을 사용하여 제조한 분리막의 배출수 처리 현장 적용성 test를 위한 최적 유효막 길이 선정 하기 위해, 동일한 원수, 기본 공정 조건으로 유효막 길이를 변화시켜 운전에 따른 역세 효율 및 운전압을 관찰하였다. 동일한 공정조건에서 유효막 길이의 변화를 주어 500㎜, 1,000㎜, 1,500㎜의 유효막 길이에 따라 1.5일간 고탁도의 가혹한 조건에서 공정을 지속하여 측정을 실시하였다. 유효막 길이별 운전 결과 유효막 길이에 따른 역세에 의한 효율차이를 확인할 수 있었으며 고탁도의 원수를 사용하여 중공사 막의 내부 폐색이 진행되었으며 유효막 길이가 길수록 폐색되지 않은 bore쪽으로만 역세가 진행되어 여과 후 역세에 의한 회복이 현저히 떨어짐을 확인하였다.

굴 패각과 같은 반응성 재료는 사용 목적에 적합한 전처리 조건을 선택할 필요가 있다. 본 연구에서는 인 농도 제어를 목적으로 효율적인 굴 패각 사용을 위한 전처리 조건을 제안하는데 목적을 둔다. 굴 패각의 전처리(소성 온도, 소성 시간, 입자 크기)에 따른 인산염 제거 효율을 조사하였다. 또한 XAFS 분석 및 등온 흡착 실험을 통해 굴 패각의 인산염 제거특성에 대해 조사하였다. 실험 결과 소성 온도는 600°C, 소성 시간은 6 h, 입자 크기는 0.355~0.075 mm에서 우수한 제거 효율을 확인하였다. 등온 흡착 실험 결과 Langmuir 모델이 굴 패각의 흡착에 적합한 것으로 나타났다. XAFS 분석 결과 600°C에서 소성시킨 굴 패각에는 인산칼슘이 생성된 것이 확인되었다. 즉 굴 패각의 칼슘 이온 용출에 의한 인산칼슘 형성이 인산염의 농도 감소에 기여하고 있음을 확인하였다.

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 μm 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.

무기실리카 입자로 구성된 고탁도 원수를 처리하는 침지식 정밀여과 운전에서 휴민산과 2가 양이온의 존재유무에 따라 시간에 따른 파울링 저항을 관찰하였다. 공기폭기로 인한 무기실리카 입자의 파울링 감소효과는 휴민산과 칼슘이 혼합 으로 존재 시 감소하였다. 파울링층의 전자현미경 관찰결과 칼슘의 존재 시 휴민산의 무기실리카 입자 표면흡착이 관찰되었 다. 이는 멤브레인 표면에 조밀한 파울링층을 형성시켜 공기폭기 효과를 감소시킨 것으로 판단된다. 용액의 조성에 따른 고탁 도 원수의 탁도 제거율에는 큰 변화가 없었으나 공기폭기량에 따라 칼슘과 무기실리카 입자의 혼합 존재 시 유기물질의 제거 율은 80% 이상으로 증가하였다. 이는 공기폭기 하에 무기실리카 입자 표면에 흡착된 일부 휴민산들이 멤브레인 표면으로부 터 함께 역수송 되어 유기물질 제거율을 증가시킨 것으로 사료된다.

Modified coagulants were investigated for the removal of phosphorus from secondary effluent of wastewater treatment. The modified coagulants were prepared by mixing alkali earth metal ions such as calcium and magnesium. The basicity of a coagulant influenced on the removal of phosphorus, and coagulants with basicity of 5.9% showed a better removal of total phosphorus than that of 38.5%. Also, coagulants with alkali earth metals enhanced the performance of coagulation by 10% and resulted in 67.1% for total phosphorus removal. Moreover, the removal of suspended solids and chemical oxygen demand was improved using coagulants with low basicity and earth metal ions. Results of this study demonstrated that the use of coagulants with low basicity, and calcium and magnesium ions is recommended to improve wastewater effluent quality.

CRISPRs(clustered regularly interspaced short palindromic repeats) / CRISPR - associated(CAS) system has been used genome editing technology. Genome stage modification using CRISPR/CAS9 system can be used to wide research for the gene functional study and therapeutics. However, improving of CRISPR/CAS9 system in efficiency is essential for application in various fields. Here, we treated various chemicals during the procine early embryo development to increase the mutation of target site by NHEJ(non-homologous end joining). Firstly, we confirmed the chemical toxicity after parthenogenetic activation and then check embryo puality using by counting of total cell number and TUNEL Assay in blastocyst satge. To check any improvement on mutation rate by NHEJ pathway. AZT(3′-Azido-3′-deoxythymidine, antiretroviral drug – 0.1 μM) was treated after injection of cas9 and sgRNA target to OCT4 exon 5 during the zygote stage, followed by PCR sequencing. As a result, AZT treated group shows a significantly increased in knock-out efficiency as a consequence of NHEJ. Nocodazole(anti-neoplastic agent – 200ng/ml), RO-3306 (specific inhibitor of CDK1 - 10 μM) and NU-7026(PKC signalling inhibitor - 50 μM) was treated after injection of cas9 and sgRNA with eGFP vector during the zygote stage(hpa8~hpa20) and checked a efficiency of knock-in by PCR sequencing. Interestingly, nocodazole treatment groups increased of insertion of eGFP sequence in blastocyst stage compared with non-treat group(control : 8.33%, nocodazole treatment : 16.67%). However, RO-3306 and NU-7026 made a no impact. In summary, CRISPR/CAS9 system with treatment of chemicals during porcine embryogenesis can be improving of site-specific mutation and enhancement of CRISPR genome editing.

This study was performed to evaluate the alternative improvement plans for removal efficiency of plating wastewater treatment processes with high concentrations of heavy metals and total nitrogen in the influent. The average removal efficiency rates of the existing wastewater treatment plant were 58% of CODcr, 74% of CODmn, 78% of TN, 99% of TP, respectively. However, the concentration of SS (about 250 mg/L) was over the emission standard (120 mg/L). TN and Cu2+ concentrations were over the emission standard; about 62 mg/L and 5.2 mg/L, respectively. Carbon source quantity, fed into the anoxic tank of the biological wastewater treatment process, was controled by calculating the optimum required COD amount for denitrification. The removal efficiency rates of Zn2+, Cu2+, and Ni2+ were achieved using an electrolysis reactor 89%, 89%, and 99%, respectively. Therefore, it was recommended to modify the existing wastewater treatment process including the chemical precipitation to the electrolysis reactor as an efficient and environmentally effective alternative.

저농도 합성폐수를 처리하는 membrane bioreactor (MBR) 시스템에서 공기폭기와 PET (polyethertaraphtalate) 입상메디아 혼합사용이 멤브레인 파울링과 처리효율에 미치는 영향을 관찰하였다. 일정한 공기폭기유량과 투과플럭스로 실험한 결과, PET 메디아를 첨가 시 메디아를 첨가하지 않은 경우보다 낮은 파울링 속도가 관찰되었다. MBR 반응기에서 입상 메디아에 의한 파울링 감소효과는 중공사막 모듈에 비해 평막 모듈이 더욱 효과적이었다. 공기폭기와 함께 멤브레인 표면을 따라 움직이는 입상 메디아의 접근성과 접촉성이 중공사막보다 효과적이었던 것으로 사료된다. MBR 적용에 있어 PET 메디아의 적용은 메디아를 적용하지 않았을 때와 비교 시 MBR 처리효율에 큰 영향을 주지 않았다.

The heat treatment machine based on immersion was developed to reduce temperature difference during netting process and appraised it performance compared current heat treatment machine using high pressure. It was also reviewed the optimum heat treatment procedures for PBSAT monofilament net in accordance with the immersion time and temperature. The procedure was based on physical measurement such as breaking load, elongation and angle of the mesh for PBSAT monofilament. The water temperature gap of the treatment machine based on immersion was less than 1°C. and the energy consumption was also increased in high temperature condition. It was identified that the optimum temperature was 75°C and its optimum processing time was between 15 minutes and 20 minutes to get qualified physical properties.

수돗물 공급에 있어서의 미량 유기물질 및 맛냄새 제거의 중요도가 높아짐에 따라 오존, GAC 및 PAC 등 고도 정수처리공정의 도입이 지속적으로 증대되고 있다. 하지만, 원수의 수질악화, 새로운 오염물질의 출현 등에 의해 기존의 고도처리공정이 향후에도 충분한 대안이 된다고 확신하기는 어려운 실정이다. 본 연구에서는 고농도의 분말활성탄을 slurry blanket의 형태로 체류시킨다는 새로운 개념의 접촉조를 구상, 막여과조와 연계하여 하나의 공정으로 완성하였다. 한강원수를 대상으로 80m3/일 규모의 pilot plant를 이용, 유기물질 및 2-MIB, Geosmin에 대한 제거특성을 살펴본 결과 DOC의 경우 운영초기 90% 이상, 안정화된 이후에도 70~80% 내외의 높은 처리효율을 나타내었으며 2-MIB Geosmin의 경우 검출한계 이하로 제거되었다. 본 공정은 1년 이상의 장기간의 고도처리 효율 검증 및 안정된 PAC 접촉조의 운영방안 등 공정 최적화를 위한 추가적인 연구가 필요한 실정이나 기존의 고도처리에 비해 컴팩트하면서 높은 처리효율을 안정적으로 나타냄으로써 맛냄새물질을 비롯한 미량 오염물질을 제거하기 위한 대안공정으로서의 높은 가능성을 확인하였다.

본 연구에서는 4종류의 관형 세라믹 정밀 및 한외여과막(탄소 재질)으로 제지공장의 방류수를 물로 주기적 역세척하면서 여과하였을 때, 최적 역세척 시간을 규명하였다. 각 분리막에 대상으로 물 역세척 시간의 영향을 살펴 본 결과, 분리막의 기공이 클수록 길게 역세척 하는 것이 가장 많은 총여과부피, 즉 처리수의 회수 효율이 높기 때문에 가장 효과적이라 할 수 있다. 한편, 180분 동안 여과하면서 초기투과선속에 대한 투과선속의 변화를 살펴본 결과, 정상운전시간이 길수록 막오염이 많이 진행된 상태이므로 역세척 시간을 길게 해주여야만 막오염을 억제하여 높은 투과선속을 유지할 수 있다는 것을 알 수 있었다. 또한, 막오염의 저항 변화 추이를 관찰하여 최적 물역세척 시간을 규명해 보아도, 투과선속의 변화로부터 얻은 최적 역세척 시간과 거의 동일한 결과를 얻을 수 있었다.

균일한 밀집구조를 지니는 투명한 폴리설폰 필름이 용매를 사용한 표면처리를 통해 개질되었다. 개질은 고분자 필름을 디메털포름아마이드 용매에 1 sec간 담그고 이를 비용매 욕조에 침지시켜 이루어졌다. 개질 전 투명하였던 필름은 개질 후 횐색을 띠며, 많은 기공이 표면에 형성되었다. 비용매로서 물을 사용하였을 때가 이소프로파놀을 사용하였을 때 보다 표면의 불균일도가 증가하였다. 개질된 필름을 사용하여 방사성핵종으로 오염된 지역으로부터 오염물을 채취하였을 때 일반적으로 사용되는 필터페이퍼를 사용하는 것보다 우수한 채취 효율을 보여주었다. 개질된 필름 중에서는 비용매로 물을 사용한 경우 이소프로파놀을 이용한 필름보다 오염물의 채취 효과가 좋은 것으로 나타났다. 한편, 개질된 필름은 고분자 필름의 양쪽 겉표면만을 변화시켜, 필름의 내부는 고유한 밀집도를 유지함으로써, 필터페이퍼 또는 유리섬유를 사용한 오염물 제거 과정에서 나타날 수 있는 매체의 기공을 통한 2차적 오염을 방지하는 효과가 있다.