인 제거 소재를 활용한 여과수로의 인 제거효율 및 현장적용성

장여주,임현만,안광호,김원재 대한환경공학회 2018 대한환경공학회 학술발표논문집 Vol.2018 No.11

파일럿 플랜트 규모에서 일체형 침전부상공정 (SeDAF)의 설계인자 및 운전특성에 대한 실증적 평가

장여주,정진홍,임현만,김원재 대한상하수도학회 2021 상하수도학회지 Vol.35 No.1

Eutrophication and algal blooms can lead to increase of taste and odor compounds and health problems by cyanobacterial toxins. To cope with these eco-social issues, Ministry of Environment in Korea has been reinforcing the effluent standards of wastewater treatment facilities. As a result, various advanced phosphorus removal processes have been adopted in each wastewater treatment plant nation-widely. However, a lot of existing advanced wastewater treatment processes have been facing the problems of expensive cost in operation and excessive sludge production caused by high dosage of coagulant. In this study, the sedimentation and dissolved air flotation (SeDAF) process integrated with sedimentation and flotation has been developed for enhanced phosphorus removal in wastewater treatment facilities. Design and operating parameters of the SeDAF process with the capacity of 100 m3/d were determined, and a demonstration plant has been installed and operated at I wastewater treatment facility (located in Gyeonggi-do) for the verification of field applicability. Several empirical evaluations for the SeDAF process were performed at demonstration-plant scale, and the results showed clearly that T-P and turbidity values of treated water were to satisfy the highest effluent standards below 0.2 mg/L and 2.0 NTU stably for all of operation cases.

저수심 저수지에 적용 가능한 무동력 수류순환시스템의 수질개선 효과

장여주,임현만,정진홍,박재로,장향연,박나리,김원재 대한환경공학회 2018 대한환경공학회지 Vol.40 No.11

A large number of reservoirs in Korea have experienced eutrophication and deterioration of water quality including the occurrence of algal blooms, anaerobic state near the bottom due to excessive oxygen consumption, and the elution of nutrients from the sediment. Non-powered water circulation system inducing downward flow from wind-driven current has been developed for domestic reservoirs with shallow water depth. One of the functions of the system is to improve water quality by breaking thermal stratification and prohibiting anaerobic condition near the bottom. The monitoring results of the test-bed, which have been observed for 1 year, showed clearly that the circulation system could maintain DO (dissolved oxygen) concentration higher than 5 mg/L in deep layer (hypolimnion) and also mitigate DO supersaturation about 17% in surface layer (epilimnion). 한국의 저수지들은 부영양화 및 수질악화 문제를 지속적으로 겪고 있으며, 녹조의 대발생, 저층의 산소소비량 증가와 빈 산소화(혐기화) 및 저질층에서의 영양염류 용출 등의 문제가 발생한다. 얕은 수심을 갖는 국내 저수지의 수질문제를 저감하기 위한 무동력 수류순환시스템을 개발하였다. 해당 시스템은 바람과 수류에너지를 이용하여 표층수의 하강순환을 유도함으로써 수 층의 성층화와 저층의 빈산소화를 방지하고 수질을 개선한다. 해당 시스템을 적용한 테스트베드를 구축·운영한 결과, 1) 심층의 빈산소화를 개선하여 DO(용존산소)를 5 mg/L 이상으로 유지하며, 2) 표층의 DO 과포화를 약 17% 감소시키는 효과가 관찰되었다.

하수처리시설에서 인 고도처리를 위한 일체형 침전부상공정(SeDAF)의 응집제 주입농도 자동제어기법 검토

장여주,정진홍,김원재,Jang, Yeoju,Jung, Jinhong,Kim, Weonjae 대한상하수도학회 2020 상하수도학회지 Vol.34 No.6

To remove phosphorus from the effluent of public wastewater treatment facilities, hundreds of enhanced phosphorus treatment processes have been introduced nationwide. However, these processes have a few problems including excessive maintenance cost and sludge production caused by inappropriate coagulant injection. Therefore, the optimal decision of coagulant dosage and automatic control of coagulant injection are essential. To overcome the drawbacks of conventional phosphorus removal processes, the integrated sedimentation and dissolved air flotation(SeDAF) process has been developed and a demonstration plant(capacity: 100 ㎥/d) has also been installed. In this study, various jar-tests(sedimentation and / or sedimentation·flotation) and multiple regression analyses have been performed. Particularly, we have highlighted the decision-making algorithms of optimal coagulant dosage to improve the applicability of the SeDAF process. As a result, the sedimentation jar-test could be a simple and reliable method for the decision of appropriate coagulant dosage in field condition of the SeDAF process. And, we have found that the SeDAF process can save 30 - 40% of coagulant dosage compared with conventional sedimentation processes to achieve total phosphorus (T-P) concentration below 0.2 mg/L of treated water, and it can also reduce same portion of sludge production.

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.

저수지 수질개선을 위한 무동력 하향류 수류순환시스템의 현장적용성

장여주,임현만,정진홍,박재로,김원재 응용생태공학회 2019 Ecology and resilient infrastructure Vol.6 No.2

Eutrophication has occurred due to the inflow of various water pollutants in many Korean reservoirs with low depth, and algal blooms of surface layer and low oxygenation of deep layer have repeated every year. There are several existing technologies to alleviate the stratification of reservoirs, but it is difficult to apply them in field sites due to the necessity of electric power and low economic efficiency. In this study, a non-powered water circulation system using natural energy of wind and water flow has been developed, and two test-beds constructed in the reservoirs with different conditions and examined its field applicability. Through computational fluid dynamics (CFD) simulation, it has been shown that the water circulation system could induce the downward flow to mitigate the stratification between surface and deep layers, and its influence radius could reach about 30 m. As a result of long-term monitoring of the test-beds, various water quality improvement effects have been observed such as moderation of DO fluctuation by water circulation, reduction of DO supersaturation and prevention of excessive pH rising. In order to improve the applicability of the water circulation system, it is considered necessary to review countermeasures against flood and depth conditions of each reservoir. 국내의 많은 저수심 저수지들은 다양한 수질오염물질의 유입으로 인해 부영양화가 진행되고 있으며, 해마다 반복적으로표층의 녹조 발생과 저층의 빈산소화를 겪고 있다. 이를 방지하기 위한 대책으로 저수지의 성층현상을 완화하는 기존 기술들이있으나 대부분 동력이 필요하며 비경제적인 측면으로 인해 도입이 어려운 실정이다. 본 연구에서는 바람과 수류의 자연에너지를활용하는 무동력 수류순환시스템을 개발하고 상이한 조건을 갖는 두 저수지를 대상으로 테스트베드를 구축, 운영하여 현장적용성을검토하였다. 수류순환시스템을 모사한 전산유체역학 (CFD) 모의 결과, 하향류가 유도되어 표층과 심층 사이의 성층현상을 완화시키고, 영향반경은 약 30 m에 달하는 것으로 해석되었다. 테스트베드에 대한 장기 모니터링 결과, 수류순환 작용에 의해 DO의 변동을 완만하게 하고, DO 과포화 현상을 저감하며, pH의 과도한 상승을 방지하는 등 다양한 수질개선 효과가 관찰되었다. 본 수류순환시스템의현장적용성을 제고하기 위해서는 홍수시 및 저수심 조건에 대한 대응방안 마련이 필요한 것으로 판단된다.

남조류 제거를 위한 천연조류제거제(W.H.)의 최적주입농도 결정

장여주,정진홍,임현만,윤영한,안광호,장향연,김원재 대한환경공학회 2016 대한환경공학회 학술발표논문집 Vol.2016 No.11

천연조류제거제를 활용한 응집･부상 전처리공정의 기존 응집공정 대체 가능성

장여주,정진홍,임현만,장향연,김원재 대한상하수도학회 2017 상하수도학회지 Vol.31 No.1

In the coagulation/sedimentation (C/S) process of the water treatment process, the inflow of massive algal bloom causes many problems including fouling of filter media. This study was conducted to find out the way to remove the algae’s harmful effects by addition of pre-treatment prior to C/S process. Many Jar-tests were conducted such as ① ACF (Algae Coagulation·Flotation) process using natural algae coagulant (Water Health®), ② ACF + C/S process and ③ C/S process with a variety of conditions using cultured algae. The average values of turbidity were ① 0.42 NTU for ACF process, ② 0.13 NTU for ACF + C/S process and ③ 0.25 NTU for C/S process. It was shown that the treatment efficiency of ACF process could get low turbidity results, and ACF + C/S process could achieve more efficient results than those of C/S process. Any negative effects of ACF process to the efficiency of C/S process were not observed in ACF + C/S process. In order to reduce the unfavorable effects of algae, it was found out that the introduction of ACF process in the forms of ① ACF or ② ACF + C/S could be one of the effective and alternative solutions.

인 고도처리 최적화를 위한 일체형 침전부상 공정의 운전효율 평가

장여주,정진홍,임현민,박나리,장향연,김원재 대한환경공학회 2019 대한환경공학회 학술발표논문집 Vol.2019 No.12

천연조류제거제를 활용한 응집・부상 전처리공정의 기존 응집공정 대체 가능성

장여주,정진홍,임현만,장향연,김원재 대한상하수도학회 2017 상하수도학회지 Vol.31 No.1

In the coagulation/sedimentation (C/S) process of the water treatment process, the inflow of massive algal bloom causes many problems including fouling of filter media. This study was conducted to find out the way to remove the algae's harmful effects by addition of pre-treatment prior to C/S process. Many Jar-tests were conducted such as ① ACF (Algae Coagulation·Flotation) process using natural algae coagulant (Water Health®), ② ACF + C/S process and ③ C/S process with a variety of conditions using cultured algae. The average values of turbidity were ① 0.42 NTU for ACF process, ② 0.13 NTU for ACF + C/S process and ③ 0.25 NTU for C/S process. It was shown that the treatment efficiency of ACF process could get low turbidity results, and ACF + C/S process could achieve more efficient results than those of C/S process. Any negative effects of ACF process to the efficiency of C/S process were not observed in ACF + C/S process. In order to reduce the unfavorable effects of algae, it was found out that the introduction of ACF process in the forms of ① ACF or ② ACF + C/S could be one of the effective and alternative solutions.