전산화 공정에 의한 microcystin 용출 및 고도처리에 의한 제거 특성

염훈식,손희종,류지승,정은영,김경아 대한환경공학회 2019 대한환경공학회지 Vol.41 No.10

목적 : 하절기 고농도의 Microcystis sp. 함유 원수가 정수장으로 유입시에 전산화 공정에서의 microcystin (MCs) 용출과 후단의 고도 정수처리 공정에서 용출된 MCs의 제거 가능성 평가가 목적이다. 방법 : 고농도 Microcystis sp. 함유원수(400,000 cells/mL)를 이용하여 전염소와 전오존 처리에 의한 MCs 용출 특성을 평가하였으며, 후단의 고도 정수처리 공정인 O3, O3/H2O2, UV/H2O2 및 BAC 공정에서의 전산화 처리에 의해용출된 MCs 제거 특성을 평가하였다. 결과 및 토의 : 전염소 투입농도가 증가할수록 수중으로 용출된 MCs 농도는 급격히 증가하다가 염소 투입농도 5 mg/L 이상에서는 감소하였고, 용출된 MCs의 대부분은 MC-RR (57∼86%)과 MC–LR (11∼29%)이 차지하였다. 전염소 처리 이후 전오존 처리공정에서 오존 투입농도가 증가할수록 수중의 MCs 농도는 처리 전에 비해 수∼수십배 정도 증가하였으나, 전염소를 3 mg/L 이상으로 처리한 경우에는 오존 투입농도가 증가할수록 MCs가 급격히제거되었다. 전산화 처리 후, 응집-침전 처리수 중의 MCs 농도가 처리 전에 비하여 2배 이상 급격히 증가였으며, 침전공정 동안 산화제에 손상된 Microcystis 조체에서 MCs가 지속적으로 유출되었다. 후산화 공정에서는 O3과O3/H2O2 공정이 UV/H2O2 공정에 비해 MCs 제거에 효과적이었고, O3과 O3/H2O2 공정에서 1 mg/L 이상으로 O3을투입한 경우 MCs가 100% 제거되었다. BAC 공정에서는 MCs 유입농도가 각각 0.8 μg/L와 2.8 μg/L일 때 EBCT 15분에서 각각 100%와 93% 제거되었으며, MC-RR에 비해 MC-LR의 생물분해 제거능이 낮았다. 고농도의 MCs가유입되거나 MC–LR의 구성비율이 높을 경우에는 BAC 공정의 EBCT를 증가시켜 운전할 필요가 있었다. 결론 : 고농도 Microcystis sp. 함유 원수를 전산화 처리하면 고농도의 MCs이 용출되었으나 후단의 O3, O3/H2O2, UV/H2O2 및 BAC 공정과 같은 고도 정수처리 공정에서 제거가 가능하였다. 특히, UV-AOP 공정에 비해 O3 공정에의한 MCs 제거율이 높았으며, BAC 공정에서도 EBCT 15분의 조건에서는 93∼99%의 MCs가 제거되었다. Microcystis sp.가 번성하는 시기에 응집/침전 공정의 효율 증진을 위해 전산화 공정을 적용하는 정수장에서는 후단에 O3/BAC 공정을 적용할 경우 MCs 제거에 매우 효과적으로 나타났다. Objectives : The objectives of this study were to evaluate the characteristics of microcystins (MCs) release form Microcystis sp. in surface water during pre-oxidation process using chlorine and ozone and it’s removal by advanced water treatment process as post process when raw water containing high Microcystis sp. is introduced into the water treatment plant. Methods : Raw water which had contained over 400,000 cells/mL of Microcystis sp. were used to evaluate the characteristics of MCs released from Microcyctis sp. and chlorination (Cl2) and ozonation (O3) were used as pre-oxidation process and O3, O3/H2O2, UV/H2O2 and biological activated carbon (BAC) were used as post oxidation process. Results and Discussion : As the concentration of chlorine increased, the concentration of released MCs in the water increased, but decreased when higher than 5 mg/L of chlorine dosage. Released MCs were consisted of almost MC-RR (57∼86%) and MC–LR (11∼29%). In the ozone treatment after prechlorination process, the MCs concentration was increased by several fold to dozen fold to compare before ozonation. However, when chlorine dosage was over 3 mg/L, MCs were rapidly removed as the ozone concentration increased. The MCs concentration of flocculation/sedimentation treated sample after the pre-oxidation was increased more than two times before treatment, the MCs was continuously released during the coagulation/sedimentation process from the damaged Microcystis sp. due to the prior oxidation process. In the post-oxidation process, O3 and O3/H2O2 processes were more effective for removing MCs than the UV/H2O2 process, and O3 and O3/H2O2 processes removed 100% of the MCs when O3 was added above 1 mg/L. 100% and 93% were removed respectively at 15 minutes of EBCT (empty bed contact time) in the BAC process, when the MCs concentrations of influent were 0.8 μg/L and 2.8 μg/L. The biodegradability of MC-LR was lower than that of MC-RR. It was necessary to increase the EBCT of the BAC process when the concentrations of MCs or the ratio of MC-LR were high. Conclusions : Although, pre-oxidation treatment to the raw water containing high concentration of Microcystis release higher MCs concentration in the oxidized water, that can be removed by post O3, O3/H2O2, UV/H2O2 and BAC processes. The removal rate of MCs by O3 process was higher than that of UV-AOP process, and 93∼99% of MCs removed with 15 min of EBCT in BAC process. In the drinking water treatment plant where the pre-oxidation process is applied to improve the efficiency of the flocculation/sedimentation process during the blooming season of Microcystis sp., O3/BAC process after the flocculation/sedimentation process is recommendable to MCs remove.

중수 재이용을 위한 오존 고도산화 및 세라믹 분리막 일체형 공정의 최적화 연구

이종훈,노호정,박광덕,우윤철 한국물환경학회 2021 한국물환경학회지 Vol.37 No.6

The aim of this study was to optimize the ozonation and ceramic membrane integrated process for greywater reclamation. The integrated process is a repeated sequential process of filtration and backwash with the same ceramic membrane. Also, this study used ozone and oxygen gas for the backwashing process to compare backwashing efficiency. The study results revealed that the optimum filtration and backwash time for the process was 10 minutes each when comparing the filtrate flow and membrane recovery rate. The integrated process was operated at three different operating conditions with i) 10 minutes for filtration and 10 minutes for ozonation, ii) 10 minutes for filtration and 10 minute for oxygen aeration, and iii) continuous filtration without any aeration for synthetic greywater. The integrated process with ozone backwashing could produce 0.55 L/min of filtrate with an average of 18.42% permeability recovery, while the oxygen backwashing produced 0.47 L/min and 6.26%, respectively. And without any backwashing, the integrated process could produce 0.29 L/min. This shows that the ozone backwash process is capable of periodically recovering from membrane fouling. The resistance of the fouled membrane was approximately 34.4% for the process with ozone backwashing, whereas the resistance was restored by 10.8% for the process with oxygen backwashing. Despite the periodical ozone backwashing and chemical cleaning, irreversible fouling gradually increased approximately 3 to 4%. Approximately 97.6% and 15% turbidity and TOC were removed by ceramic membrane filtration, respectively. Therefore, the integrated process with ozonation and ceramic membrane filtration is a potential greywater treatment process.

하수처리수의 3차처리를 위한 고도산화법(AOP)의 적용성에 관한 연구

정은호 ( Eunho Chung ),정종태 ( Jongtai Jung ),한상윤 ( Sangyun Han ) 한국수처리학회 2021 한국수처리학회지 Vol.29 No.5

Ozone has been applied in combination with various processes for the tertiary treatment of municipal wastewater. However, in Korea, the ozone process is mainly employed for the reuse of tertiary treated wastewater, and an enhanced advanced oxidation process (AOP) is needed to realize the large-scale reuse of treated wastewater. In this study, various AOPs employing ozone (only ozone process, O₃+H₂O₂, O₃+UV, O₃+GAC) were used to analyze the TOC, CODcr, and color treatment efficiencies of municipal wastewater and evaluate its applicability of wastewater reuse. The O₃+H₂O₂ process showed the highest TOC removal efficiency of 62.0%, while the O₃+GAC and only ozone processes exhibited the TOC removal efficiencies of 58.9% and 59.3%, respectively. The TOC removal pattern of the O₃+UV process was similar to that of the O₃+H₂O₂ process. The TOC removal efficiency of the O₃+UV process, 61.0%, was slightly lower than that of the O₃+H₂O₂ process. The CODcr removal efficiencies of the O₃+UV and O₃+H₂O₂ processes were 75.8% and 77.0%, respectively. However, the TOC and CODcr removal efficiencies were different within the error range, so there was no significant difference in the processing efficiencies of the methods investigated. The color removal efficiencies of the O₃+UV (57.8%) and O₃+H₂O₂ (57.4%) processes were 57.8%, 57.4%. respectively and it showed similar pattern.

소화탈리액 대상 오존 전처리와 Ultra Violet-Advanced Oxidation Process 연계 처리를 통한 유기물질 지표 개선

이재엽,김일호,제스민아터 대한상하수도학회 2023 상하수도학회지 Vol.37 No.5

Bioreactors are devices used by sewage treatment plants to process sewage and which produce active sludge, and sediments separated by solid-liquid are treated in anaerobic digestion tanks. In anaerobic digestion tanks, the volume of active sludge deposits is reduced and biogas is produced. After dehydrating the digestive sludge generated after anaerobic digestion, anaerobic digested wastewater, which features a high concentration of organic matters, is generated. In this study, the decomposition of organic carbon and nitrogen was studied by advanced oxidation process. Ozone-microbubble flotation process was used for oxidation pretreatment. During ozonation, the TOC decreased by 11.6%. After ozone treatment, the TOC decreased and the removal rate reached 80.4% as a result of the Ultra Violet-Advanced Oxidation Process (UV-AOP). The results with regard to organic substances before and after treatment differed depending on the organic carbon index, such as CODMn, CODCr, and TOC. Those indexes did not change significantly in ozone treatment, but decreased significantly after the UV-AOP process as the linkage treatment, and were removed by up to 39.1%, 15.2%, and 80.4%, respectively. It was confirmed that biodegradability was improved according to the ratio of CODMn to TOC. As for the nitrogen component, the ammonia nitrogen component showed a level of 3.2×10 2 mg/L or more, and the content was maintained at 80% even after treatment. Since most of the contaminants are removed from the treated water and its transparency is high, this water can be utilized as a resource that contains high concentrations of nitrogen.

고도산화-응집공정에 의한 복합도금폐수의 고농도유기물 및 중금속 제거

김종수 ( Jong-su Kim ),윤조희 ( Cho-hee Yoon ) 한국수처리학회 2016 한국수처리학회지 Vol.24 No.6

Recently plating industry has a tendency to introduce a composite plating process to help reduce costs and simplify metal plating process. However, the treatability of a composite plating wastewater containing complexed heavy metals as nickel and zinc by conventional coagulation process has a limit. Therefore, the study focused on the effect of operation parameters on each system treatability performance in terms of nickel and zinc and organics, and then is to research the optimum process. The proposed processes were experimentally investigated in a combined system of the lab-scale advanced oxidation processes(AOPs) as Fenton or Fenton-like and Electrolysis-Fenton/Fenton-like with coagulation. The results indicated that all proposed processes in this study could be almost removed Zn completely and an electro-Fenton process with hydroxide precipitation was the best among these processes. In the field wastewater test of that process, a value of obtained results was observed with Ni 48.2mg/L to 10.3mg/L, Zn 126.7mg/L to 0.6mg/L, and COD_Mn is shown to be reduced from 2560mg/L to 230.4mg/L. The optimum operating condition for the electro-Fenton process was as follows; the electrolysis reaction time 10min, an applied current density of 3.74mA/cm² at bipolar type reactor packed by granular activated carbon(GAC) and Fenton`s reaction time 60min at the initial pH 5.0 and Fe(II)/H₂O₂ 20mM/600mM.

낙동강 하류원수를 대상으로 모의 고도 정수처리공정을 이용한 N-Nitrosamine류 제거능 평가

김경아,손희종,서창동,염훈식,송미정,류동춘 대한환경공학회 2019 대한환경공학회지 Vol.41 No.1

In this study, 8 nitrosamines (N-nitrosodimethylamine (NDMA), N-nitrosomethylethylamine (NMEA), N-nitrosopyrrolidine (NPYR), N-nitrosodiethylamine (NDEA), N-nitrosopiperidine (NPIP), N-nitrosomorpholine (NMOR), N-nitrosodi-n-propylamine (NDPA), N-nitrosodi-n-butylamine (NDBA)) were spiked into rapid sand-filtration water and post-ozone treatment water and the removal efficiencies in post-ozone (O3), O3/hydrogen peroxide (H2O2), ultraviolet (UV), UV/H2O2 and biological activated carbon (BAC) processes were simulated on a laboratory scale. As a result of simulating the O3 and O3/H2O2 processes at the drinking water treatment plant (DWTP) with O3 input concentration of 2 mg/L for short chain-nitrosamines such as NDMA, NMEA and NDEA, the removal efficiency was as low as 40% or less. On the other hand, long chain-nitrosamines and aliphatic cyclic structures such as NDPA, NPYR, NMOR, NPIP and NDBA showed relatively high removal efficiencies of about 40% to 90%. The removal efficiencies of nitrosamines in UV alone and in UV/H2O2 processes were 59~96% (UV dosage: 500 mJ/cm2) and 86~100% (UV dosage: 1000 mJ/cm2), respectively. The removal efficiency of UV/H2O2 process was almost similar to that of UV alone process. In the BAC process, NDMA showed the highest removal efficiency among 8 nitrosamines. The removal efficiencies of NDMA were 71% and 94%, respectively, when water temp. were 10℃ and 25℃ and EBCT was 15 min. In the case of NMOR with the lowest removal efficiencies, the removal rates were 27% and 42%, respectively. The removal efficiencies in the BAC process were in the order of NDMA, NMEA, NDEA, NDPA, NDBA, NPYR, NPIP and NMOR. In order to effectively control of nitrosamines in large scale DWTPs located downstream of the Nakdong River, an advanced oxidation process based on UV is more suitable than the O3 and O3/H2O2 processes currently in operation. In the case of the O3 and O3/H2O2 processes, it was also evaluated that it is possible to efficiently control the nitrosamines introduced into the DWTP when operated in combination with BAC process. 본 연구에서는 급속모래 여과수와 후오존 처리수에 8종의 nitrosamines (N-nitrosodimethylamine (NDMA), N-nitrosomethylethylamine (NMEA), N-nitrosopyrrolidine (NPYR), N-nitrosodiethylamine (NDEA), N-nitrosopiperidine (NPIP), N-nitrosomorpholine (NMOR), N-nitrosodi-n-propylamine (NDPA), N-nitrosodi-n-butylamine (NDBA))를 투입하여 후오존, 후오존/과산화수소, 자외선, 자외선/과산화수소 및 생물활성탄 공정에서의 제거능을 실험실 규모의 실험장치로 모사하였다. NDMA, NMEA 및 NDEA와같은 단쇄 nitrosamine류들에 대해 오존 투입농도를 2 mg/L로 하여 정수장에서의 후오존 및 후오존/과산화수소 공정을 모사한 결과, 40% 이하의 낮은 제거율을 나타내었다. 반면 NDPA, NPYR, NMOR, NPIP 및 NDBA와 같은 장쇄 및 지방족 고리구조를 가지는 nitrosamine류들은 40~90% 정도의 비교적 높은 제거율을 나타내었다. 정수장의 후오존 공정을 대체할 목적으로자외선 단독공정과 자외선/과산화수소 공정에서의 nitrosamine류들에 대한 제거능을 모사한 결과, 자외선 단독공정에서 조사량 500 mJ/cm2과 1000 mJ/cm2일 때의 제거율이 각각 59~96% 및 86~100%로 나타났으며, 자외선/과산화수소 공정에서의 제거율은 UV 단독공정과 거의 유사하게 나타났다. 생물활성탄 공정에서의 nitrosamine류 8종의 제거능을 모사한 결과, 가장 높은제거율을 나타낸 물질은 NDMA였으며, 수온이 10℃와 25℃일 때 EBCT 15분에서의 제거율이 각각 71%와 94%였으며, 가장낮은 제거율을 나타낸 NMOR의 경우는 각각 27%와 42%의 제거율을 나타내었다. 생물활성탄 공정에서의 제거율은 NDMA, NMEA, NDEA, NDPA, NDBA, NPYR, NPIP, NMOR 순이었다. 낙동강 하류에 위치한 대규모 정수장에서 nitrosamine류의 효과적인 제어를 위해서는 현재 운영 중인 후오존 및 후오존/과산화수소 공정 보다는 자외선을 기반으로 하는 고도 산화공정이 적합하였으나 후오존 및 후오존/과산화수소 공정의 경우도 후단의 생물활성탄 공정과 조합하여 운영하면 정수장으로 유입된 nitrosamine류에 대해 효율적인 제어가 가능한 것으로 평가되었다.

Oxidation byproducts from the degradation of dissolved organic matter by advanced oxidation processes – A critical review

Ike, Ikechukwu A.,Karanfil, Tanju,Cho, Jinwoo,Hur, Jin Elsevier 2019 Water research Vol.164 No.-

<P><B>Abstract</B></P> <P>Advanced oxidation processes (AOPs) have been increasingly used for the treatment of source waters and wastewaters. AOPs characteristically produce oxidation byproducts (OBPs) from the partial degradation of dissolved organic matter (DOM) and/or the transformation of inorganic ions (especially, halides) into highly toxic substances including bromate and halogenated organic OBPs (X-OBPs). However, despite the enormous health and environmental risks posed by X-OBPs, an integral understanding of the complex OBP formation mechanisms during AOPs is lacking, which limits the development of safe and effective AOP-based water treatment schemes. The present critical and comprehensive review was intended to fill in this important knowledge gap. The study shows, contrary to the hitherto prevailing opinion, that the direct incorporation of halide atoms (X<SUP>•</SUP>) into DOM makes an insignificant contribution to the formation of organic X-OBPs. The principal halogenating agent is hypohalous acid/hypohalite (HOX/XO<SUP>−</SUP>), whose control is, therefore, critical to the reduction of both organic and inorganic X-OBPs. Significant generation of X-OBPs has been observed during sulfate radical AOPs (SR-AOPs), which arises principally from the oxidizing effects of the unactivated oxidant and/or the applied catalytic activator rather than the sulfate radical as is commonly held. A high organic carbon/X<SUP>−</SUP> molar ratio (>5), an effective non-catalytic activator such as UV or Fe<SUP>2+</SUP>, a low oxidant concentration, and short treatment time are suggested to limit the accumulation of HOX/XO<SUP>−</SUP> and, thus, the generation of X-OBPs during SR-AOPs. At present, there are no established techniques to prevent the formation of X-OBPs during UV/chlor(am)ine AOPs because the maintenance of substantial amounts of active halogen is essential to these processes. The findings and conclusions reached in this review would advance the research and application of AOPs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Halide atoms react oxidatively than additively with dissolved organic matter (DOM). </LI> <LI> Hypohalous acid/hypohalite is the principal halogenating agent during AOPs. </LI> <LI> SO<SUB>4</SUB>.<SUP>•-</SUP> and HO<SUP>•</SUP> generate similar halogenated oxidation byproducts (X-OBPs) </LI> <LI> X-OBPs from SO<SUB>4</SUB>.<SUP>•-</SUP> AOPs are due to the catalytic activator and unactivated oxidant </LI> <LI> DOM may suppress halide atom formation of organic and inorganic X-OBPs. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Application of the Catalyst MnTACN onto Cotton Fabric as a Novel Approach in the H2O2/UV Decolourisation Process

Lidija Tušek,Lidija Fras Zemljič,Bojana Vončina,Julija Volmajer Valh 한국섬유공학회 2022 Fibers and polymers Vol.23 No.9

In this article a novel approach for a catalytic advanced oxidation process using H2O2/UV/MnTACN isinvestigated, for the decolouration of Reactive Blue 4 (RB4) containing wastewater at room temperature. The catalyst 1,4,7-trimethyl-1,4,7-triazacyclononane (MnTACN) was not added to the batch reactor where the advanced oxidation process(AOP) was carried out conventionally, but was first applied to the cotton fabric to form a suitable catalyst carrier with a highspecific surface area. With the given experimental parameters (0.777 g/l H2O2; a mercury (Hg) lamp at 500 W; 40 mg/lsolution of Reactive Blue 4; room temperature), complete decolourisation with the MnTACN catalyst was achieved in only20 minutes. When the MnTACN catalyst adsorbed on the cotton fabrics is introduced into the process as a functional textilematerial, the decolouration of RB4 is much faster, and 100 % decolouration is achieved in 10 minutes. Although pretreatmentof the fabric with acid and/or UV/ozone before application of MnTACN influences the amount of adsorbedMnTACN, the decolouration process is almost unaffected over time. Pre-treatment of fabric with chitosan before theapplication of MnTACN affects the final decolourisation rate and efficiency negatively, and does not act synergistically withthe MnTACN. The same functional fabric with adsorbed MnTACN can be used in at least 5 consecutive AOPs, which makesthe process more environmentally friendly and cost effective, but also opens the possibility to a continuous wastewatertreatment process.

미세기포 오존과 생물여과 시스템을 이용한 생활하수의 3차 처리에 관한 연구

강동한 ( Dong Han Kang ),장영호 ( Young Ho Jang ),김종수 ( Jong Su Kim ),김극태 ( Keug Tae Kim ) 한국물환경학회 2011 한국물환경학회지 Vol.27 No.6

In this paper, the removal characteristics of dissolved organic carbon (DOCs) by micro bubble ozonation process and O3/UV process were comparatively studied. In the point of DOC removing reaction coefficient, micro bubble ozonation system and O3/UV process had not significant difference, 0.0120 sec-1 and 0.0141 sec-1. Therefore micro bubble ozonation process is more suitable for tertiary treatment of sewage in the point of installation and maintenance cost-reducing. The optimum ozone injection rate was 2.0 g O3/g DOC and HRT was 3 min for the micro bubble ozonation process. The removal efficiency of DOC and SUVA in micro bubble ozonation system was 32.8% and 58.3% respective. Biological aerated filter (BAF) process was installed to remove soluble organic material increased by micro bubble ozonation system. And the effluent BOD of BAF was below 1.0 mg/L. In the view of cost-effectiveness, O3/BAF process was more profitable than O3/UV/BAF process for tertiary treatment of sewage. In order to nitrify ammonia in the BAF process completely, NH4+-N concentration in the influent water of BAF should be designed considering low water temperature in the winter season.

Decomposition of acetic acid by advanced oxidation processes

박주영,이인화 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.2

Decomposition of acetic acid, known as a non-degradable organic compound, was conducted for several advanced oxidation processes such as TiO2-UV-H2O2, Fe2+-H2O2-UV, UV-H2O2 and TiO2-UV system. Acetic acid was efficiency decomposed within 120 minutes of UV radiation under the initial concentration of 500 ppm. The initial chemical oxygen demands (CODcr) tended to increase as H2O2 was added in most reactions. However, the initial CODcr was not increased as H2O2 was consumed for the oxidation of iron salt in the photo-Fenton oxidation process. CODcr and concentration of acetic acid rapidly decreased as the mole ratio of hydrogen peroxide increased owing to rapid decomposition of the reactant at the beginning of reaction. All reactions show first order pseudo reaction rate. The CODcr removal rate and the decomposition efficiency of acetic acid were fastest in the UV-H2O2 process.