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석회계 입상알칼리재의 용출특성과 이를 이용한 인 결정화공정의 적용성
장향연,박나리,장여주,안광호,임현만,김원재 대한상하수도학회 2017 상하수도학회지 Vol.31 No.6
One of the major sources causing eutrophication and algal blooms of lakes or streams is phosphorus which comes from point and nonpoint pollution sources. HAP (hydroxyapatite) crystallization using granular alkaline materials can achieve the decrease of phosphorus load from wastewater treatment plants and nonpoint pollution control facilities. In order to induce HAP crystal formation, continuous supply of calcium and hydroxyl ions is required. In this research, considering HAP crystallization, several types of lime-based granular alkaline materials were prepared, and the elution characteristics of calcium and hydroxyl ions of each were analyzed. Also, column tests were performed to verify phosphorus removal efficiencies of granular alkaline materials. Material_1 (gypsum+cement mixed material) achieved the highest pH values in the column tests consistently, also, Material_2 (gypsum+slag mixed material) and Material_3 (calcined limestone material) achieved over pH 9.0 for 240 hours (10 days) and proved the efficiencies of long-term ion supplier for HAP crystallization. In the column tests using Material_3, considerable pH increase and phosphorus removal were carried out according to each linear velocity and filtration depth. T-P removal efficiencies were 87.0, 84.0, 68.0% and those of PO4-P 100.0, 97.0, 80.0% for linear velocity of 1.0, 2.5, 5.0 m/hr respectively. Based on the column test results, the applicability of phosphorus removal processes for small-scale wastewater treatment plants and nonpoint pollution control facilities was found out.
인 제거 입상소재를 적용한 여과수로 설계인자의 실험적 결정
장여주,김원재,임현만,정진홍,안광호,장향연,박나리 대한상하수도학회 2019 상하수도학회지 Vol.33 No.1
The algal blooms in stagnant streams and lakes have caused many problems. Excessive algae leads to disturbance of ecosystem and overload of water treatment processes. Therefore, phosphorus(P), source of algal blooms, should be controlled. In this study, a filtration trench has been developed to convert dissolved phosphorus into hydroxyapatite(HAP) so that it could be crystallized on the surface of ‘phosphorus removal granular material’; and residual particulate phosphorus could be removed by additional precipitation and filtration. The front and rear parts of filtration trench consisted of ‘phosphorus removal granular material contact bed’ and ‘limestone filtration bed’, respectively. As a result of the column test using phosphorus removal granular material and limestone serially, PO4-P was removed more than 90% when EBCT(empty bed contact time) of the contact bed was over 20 minutes; and T-P represented 60% of removal efficiency when total EBCT was over 1.5 hours. The results of column tests to figure out the sedimentation characteristics showed that more than 90% of particulate phosphorus could be removed within 24 hours. It was necessary to optimize the filtration part in order to increase removal efficiency of T-P additionally. Also, it was confirmed through the simulation of Visual MINTEQ that most of particulate phosphorus in the column tests is the form of HAP. Based on the results of the study, it could be suggested that the design parameters are over 0.5 hour of EBCT for phosphorus removal granular material contact bed and over 1.5 hours of EBCT for limestone filtration bed.
인 고도처리를 위한 일체형 침전부상공정(SeDAF)의 최적 응집제 주입조건 결정
장여주 ( Yeoju Jang ),정진홍 ( Jinhong Jung ),장향연 ( Hyangyoun Chang ),박나리 ( Nari Park ),임현만 ( Hyunman Lim ),김원재 ( Weonjae Kim ) 한국수처리학회(구 한국수처리기술연구회) 2020 한국수처리학회지 Vol.28 No.4
Algal blooms are caused by eutrophication, increased water temperature, and reduced water flow rate, and produce taste·odor compounds and health problems associated with cyanobacterial toxins. To prevent eutrophication and algal blooms, the Ministry of Environment (MOE) in Korea reinforced effluent standards for wastewater treatment facilities and, as a result, spurred the implementation of various advanced wastewater treatment processes to achieve compliance. Current tertiary wastewater treatment techniques are conventionally single processes, such as sedimentation or flotation, and have high operational costs and produce undesirable sludge problems due to excessive coagulant injection. Here, we develop a sedimentation and dissolved air flotation (SeDAF) process that integrates sedimentation and flotation for applications in advanced wastewater treatment. Jar-tests were used to evaluate water quality and treatment efficiency for sedimentation and sedimentation·flotation processes, respectively. Equations that estimate the optimal coagulant dosage are proposed to enhance the field applicability of the SeDAF process. Two types of jar-tests, both sedimentation and sedimentation·flotation, and multiple regression analyses are comprehensively examined to identify appropriate operation conditions for the SeDAF process considering fluctuations in field conditions such as T-P concentration, PO4-P / T-P ratio, turbidity, and flow rate etc.