본 연구는 이산화염소 가스를 생성하는 앰플을 이용하여 6.5 L 용기에서 살균효과와 소취효과를 확인하였고, 소독장 에서 이산화염소 가스 농도의 변화 및 S. aureus KCTC 1916 와 E. coli KCTC 1682에 대한 살균 효과를 확인하였고, 소독장안에서 작업화 내부의 살균 효과 또한 확인하였다. 앰플은 6.5 L 용기에서 S. aureus KCTC 1916와 E. coli KCTC 1682에 대해 살균 효과가 있었다. 또한 포름알데히드에 대 해서는 소취효과가 없었지만 암모니아와 페놀에는 효과가 있었다. 이산화염소 가스의 최대 농도는 앰플의 수가 많아 질수록 높아지는 것을 확인할 수 있었다. 앰플 4개는 최대 2.8 ppm, 6개일 때는 최대 4.6 ppm이었으며, 앰플 12개를 이 용하였을 때는 이산화염소 가스 농도를 측정할 수 없었지만 앰플 수와 농도가 비례적으로 상승하는 것을 고려하여 최대 8.5~9.0 ppm 으로 추정할 수 있었다. 또한 순환팬을 가동하게 되면 5배 이상의 농도 감소가 발생하였다. S. aureus KCTC 1916는 24시간 처리하였을 때 앰플 4개는 0.49 log CFU/plate, 6개는 1.2 log CFU/plate 그리고 12개는 2.98 log CFU/plate 감소되었다. E. coli KCTC 1682는 24시간을 처리하였을 때 4개, 6개, 12개 순서로 0.16 log CFU/plate, 2.68 log CFU/plate, 6.06 log CFU/plate 감소하였다. 작업화 내부에 대해 24시간 동안 처리하였을 때 앰플 6개를 사용한 경우 S. aureus KCTC 1916와 E. coli KCTC 1682 는 각각 1.22 log CFU/plate, 2.10 log CFU/plate 감소하였고 12개로 처리한 것은 2.69 log CFU/ plate, 4.41 log CFU/plate 감소하였다.

본 연구는 기구등에 오염된 E. coli와 S. aureus를 제어 하기 위해 이산화염소의 농도별 접촉시간에 따른 살균소 독력을 평가하여 살균예측모델을 개발하였다. E. coli의 경우 초기균수가 9.13 log CFU/mL이었고, 청정조건에서 5 ppm으로 1분, 3분, 5분 처리한 결과 각각 0.04, 0.07, 0.10 log CFU/mL의 감소값을 나타내었다. 20 ppm을 처리한 결 과 각각 0.74, 0.79, 0.84 log CFU/mL의 감소값을 나타내었다. 또한 CCD에 의한 최대농도 35 ppm으로 처리한 결과 각각 2.49, 2.70, 3.65 log CFU/mL의 감소값을 나타내었다. S. aureus의 경우 초기균수가 8.70 log CFU/mL이었고, 청정조건에서 5 ppm으로 1분, 3분, 5분 처리한 결과 각각 0.14, 0.28, 0.36 log CFU/mL의 감소값을 나타내었다. 20 ppm을 처리한 결과 각각 0.66, 0.79, 0.90 log CFU/mL의 감소값을 나타내었다. 또한 CCD에 의한 최대농도 35 ppm 으로 처리한 결과 각각 4.59, 5.25, 5.81 log CFU/mL의 감소값을 나타내었다. 따라서 이산화염소의 살균소독력 평 가결과는 E. coli와 S. aureus에 대하여 식품의약품안전처 살균소독력 기준에 모두 만족하는 것으로 나타났다. 살균 예측모델의 경우, R2값이 모두 0.98 이상으로 두 균주에 대해 모두 높은 적합성을 보였다. 본 연구에서 개발된 이산화염소의 살균예측모델을 식품산업 적용을 위한 기초자 료로 활용함으로써 E. coli와 S. aureus를 적절한 농도와 접촉시간으로 제어할 수 있을 것으로 사료된다.

There has been an accelerating increase in water reuse due to growing world population, rapid urbanization, and increasing scarcity of water resources. However, it is well recognized that water reuse practice is associated with many human health and ecological risks due to numerous chemicals and pathogenic microorganisms. Especially, the potential transmission of infectious disease by hundreds of pathogenic viruses in wastewater is one of the most serious human health risks associated with water reuse. In this study, we determined the response of different bacteriophages representing various bacteriophage groups to chlorination in real wastewater in order to identify a more reliable bacteriophage indicator system for chlorination in wastewater. Different bacteriophages were spiked into secondary effluents from wastewater plants from three different geographic areas, and then subjected to various doses of free chlorine and contact time at 5˚C in a bench-scale batch disinfection system. The inactivation of φX174 was relatively rapid and reached ∼4 log10 with a CT value of 5 mg/L*min. On the other hand, the inactivation of bacteriophage PRD1 and MS2 were much slower than the one for φX174 and only ~1 log10 inactivation was achieved by a CT value of 10 mg/L*min. Overall, the results of this study suggest that bacteriophage both MS2 and PRD1 could be a reliable indicator for human pathogenic viruses for chlorination in wastewater treatment processes and water reuse practice.

Study on effluent organic matter (EfOM) characteristic and removal efficiency is required, because EfOM is important in regard to the stability of effluents reuse, quality issues of artificial recharge and water conservation of aqueous system. UV technology is widely used in wastewater treatment. Many reports have been conducted on microbial disinfection and micro pollutant reduction with UV treatment. However, the study on EfOM with UV has limited because low/medium pressure UV lamp is not sufficient to affect refractory organics. The high intensity of pulsed UV would mineralize EfOM itself as well as change the characteristics of EfOM. Chlorine demand and DBPs formation is affected on the changed amounts and properties of EfOM. The objective of this study is to investigate the effect on EfOM, chlorine residual, and chlorinated DBPs formation with low pressure and pulsed UV treatment. The removal of organic matter through low pressure UV treatment is insignificant effect. Pulsed UV treatment effectively removes/transforms EfOM. As a result, the chlorine consumption is changed and chlorine DBPs formation is decreased. However, excessive UV treatment caused problems of increasing chlorine consumption and generating unknown by-products.

It has been confirmed that some Trihalomethanes (THMs) suspected as carcinogens, can be formed during chlorination for water supply through the reaction of chlorine and humic substances in water. The electrochemical characteristics on activated carbon fiber filter (ACF) electrode were investigated to remove the THMs in the chlorination process of drinking water. The electrochemical removal efficiency depended on the applied voltage and flow rate. In this study, the best result showed that the removal efficiency of THMs was higher than 99%.

Formation of disinfection by-products (DBPs) including trihalomethans (THMs) and haloacetic acids (HAAs) from chlorination of six different species (Chlorella vulgaris, Scenedesmus sp., Anabaena cylindrical, Microcystis aeruginosa, Asterionella formosa and Aulacoseira sp.) of algal extracellular organic matter (EOM). The EOM characteristics evaluation of six algal species reaching at the stationary phase in the growth curve showed most of its SUVA254 showed below 1 and this means hydrophilic organic matter is much higher than hydrophobic organic matter. Chloroform formation potential (CFFP), dichloroacetic acid formation potential (DCAAFP) and trichloroacetic acid formation potential (TCAAFP) were mainly composed of THMFP and HAAFP in the EOM of various algal species. In the case of THMFP/DOC and HAAFP/DOC values, EOM of blue-green algae has appeared highest and EOM of green algae and diatom in order. THMFP/DOC was higher than HAAFP/DOC in EOM of blue-green algae. In comparison of formation potential by unit DOC composed of HAAFP in algal species EOM, DCAAFP/DOC was 1.5 times to 7.5 time higher than TCAAFP/DOC in the EOM of blue-green algae, while DCAAFP/DOC was found to be relatively high compared to TCAAFP/DOC in the EOM of green algae and diatom.

Formation of disinfection by-products (DBPs) including trihalomethans (THMs), haloacetic acid (HAAs), haloacetonitriles (HANs) and others from chlorination of algogenic organic matter (AOM) of Microcystis sp., a blue-green algae. AOM of Microcystis sp. exhibited a high potential for DBPs formation. HAAs formation potential was higher than THMs and HANs formation potential. The percentages of dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) formation potential were 43.4% and 51.4% in the total HAAs formation potential. In the case of HANs formation potential, percentage of dichloroacetonitrile (DCAN) formation potential was 97.7%. Other DBPs were aldehydes and nitriles such as acetaldehyde, methylene chloride, isobutyronitrile, cyclobutanecarbonitrile, pentanenitrile, benzaldehyde, propanal, 2-methyl, benzyl chloride, (2-chloroethyl)-benzene, benzyl nitrile, 2-probenenitrile and hexanal.

최근 수자원 내에서 미량오염물질이 번번히 발견되고 있고(Lee, 2012) 이중 항생제 내성도 하나의 미량 오염물질로 간주 될 수 있다. 수자원내 항생제 내성 유전자는 환경 내 항생제 내성균의 증가를 일으켜 궁극적으로 병원균 내의 항생제 내성균의 증가를 초래할 수 있다(Kim et al., 2010). 소독은 병원성 미생물 및 잠재적 위해성을 가진 미생물을 불활성화 시키기 위한 공정이며, 수처리 공정에서 소독방법은 염소소독, 오존, UV 또는 전자빔이 선택되어 왔다(Gehr et al., 2003). 본 연구에서는 강력한 산화 기법중의 하나인 오존 소독과 전통적 기법인 염소소독을 비교하는데 목적이 있다.

The effect of ozone on the formation and the removal of disinfection byproducts(DBPs) of chlorination process was studied to elucidate the performance of water treatment process. The samples of raw water, prechlorination process, and preozonation process were analyzed quantitatively according to the Standard Methods for the Examination of drinking water. As a result, most of total trihalomethanes(THMs) which were formed in prechlorine treatment process was not removed in the preozonation process. Most of haloacetic acids(HAAs), haloacetonitriles(HANs), and chloral hydrate(CH) was removed in sedimentation and biological activated carbon(BAC) filtration processes. However, DBPs were increased more or less by postchlorine step. In particular, the formation of THMs and HAAs depends on ozone more than chlorine, but, the formation of HANs and CH depends on chlorine more than ozone. The seasonal variation of DBPs concentration for the year needs to be investigated to study the temperature effect because DBPs strongly depend on temperature among various efficient factors.