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Synergistic coagulation of hybrid polyaluminum ferric chloride coagulant for water treatment
Youjung Jang,Jimin Kim,Byongha Lee,Heekyong Oh 한국도시환경학회 2024 한국도시환경학회지 Vol.24 No.2
조류는 이취미 유발물질과 독소 물질을 발생시키고 정수장에서 침전 및 여과 효율을 크게 저하시킨다. 응집공정은 조류를 제거하는 방법으로 널리 사 용된다. 본 연구에서는 기존 응집제의 주원료인 알루미늄을 철로 일부 대체하여 제작한 PAC-F의 최적 철 함량을 확인하고, 응집제에 철이 포함될 경우 발 생하는 처리수의 색도 변화에 대한 문제를 해결하여 현장 적용 방안을 검토하였다. 자가 규격에 따라 제작한 PAC-F와 PAC을 대상으로 인공 배양한 규조 류의 제거 특성을 비교한 결과, PAC-F의 성능이 평균 16.5% 개선되었고, Geosmin이 최대 8%, 2-MIB가 평균 5%로 PAC에 비하여 높게 제거되었다. 탁도 및 인 제거 특성을 확인한 결과, PAC-F의 탁도 제거 성능이 19% 개선되었으며, 총인 제거에도 적합함을 확인하였다. 응집제에 포함된 적정량의 철은 처리 수 색도 발생에 영향을 미치지 않는 것으로 판단된다. PAC-F에 낮은 단가의 금속이온인 MgCl2 5%를 첨가제로 이용할 경우, PAC 대비 약 30% 이상 향상 된 탁도 제거 성능을 나타내며, 응집제 원액의 색상을 개선시킨 고염기도 PAC-F 또한 PAC와 비교했을 때 색도 및 탁도 제거 성능이 향상됨을 확인하였다. 이는 고염기도 응집제에 의한 플록 크기 향상과 그로 인한 침강성 강화에 기인한 것으로 판단된다. Algae significantly impact water purification processes by producing odor-causing substances and toxins, and decreasing the efficiency of sedimentation and filtration processes. Coagulation is widely used to address algae problems. In this study, we investigated the optimal iron content of PAC-F coagulants, which were produced by partially replacing aluminum, a primary ingredient of coagulants, with iron. We also addressed the issue of color changes in treated water caused by iron inclusion and examined practical application methods. Comparison results between self-manufactured PAC-F coagulants and PAC coagulants, based on the removal characteristics of artificially cultured Synedra species, revealed that PAC-F significantly improved algae removal efficiency by an average of 16.5%. Furthermore, PAC-F coagulants showed improvements of up to 10% and an average of 5% in the removal of Geosmin and 2-MIB, respectively. Compared to PAC coagulants, PAC-F coagulants demonstrated a 19% enhancement in turbidity removal efficiency and suitability for total phosphorus removal. Additionally, it was determined that an appropriate amount of iron did not induce color changes in the treated water. When low-cost metal ions such as MgCl2 were used as additives in the production of PAC-F coagulants, a coagulation efficiency increase of over 30% compared to PAC. Furthermore, compared to PAC, PAC-F exhibited improved color and coagulation performance when enhanced basicity. This improvement was attributed to the increased size of flocs and enhanced settling characteristics resulting from the use of advanced basicity products.
Haeng-Geun CHA,Youjung KONG,Hee Taek KIM,Jeong Chan JOO,Jung-Oh AHN,Yung-Hun YANG,See-Hyoung PARK,Kyungmoon PARK 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10
Recently, as the concerns over environmental issues have increased, the market demand for the environmental friendly bio-based chemicals isincreasing rapidly. Glutaric acid, a metabolic intermediate in amino acid pathways, is becoming a potential C5 diacid chemical as a monomer for bio-polyamide and a plasticizer to substitute petroleum based phthalate plasticizers. Since it is too toxic to produce glutaric acid by chemical process, the whole cell bioconversion process was applied in this study. In order to convert 5-aminovaleric acid (5-AVA) to glutaric acid, the enzymes, 4-aminobutyrate aminotransferase (gabT from E. coli) and succinate semialdehyde dehydrogenase (gabD from E. coli), were used. In addition, glutamate oxidase (gox from S. mobaraensis) and NAD(P)H oxidase (nox from B. subtilis) were used to regenerate cofactors, α-KG and NAD⁺, respectively. The bioconversion rate from high concentration of 5-AVA to glutaric acid was decreased after 48 hours. In order to investigate the reasons of decrease in conversion rate, the cell viability and the residual enzyme activity were analyzed. To maintain the high conversion rate, the cell exchange method was adapted in high concentration 5-AVA.