• 제목/요약/키워드: Chlorine loss

검색결과 46건 처리시간 0.036초

금속성 응집제와 모노클로라민의 상호작용이 Polyamide계 RO막 성능에 미치는 영향 (Combined Effects of Metal Coagulants and Monochloramine on Polyamide RO Membrane Performance)

  • 김경화;홍승관;박찬혁;윤성로;홍성표;이종화
    • 상하수도학회지
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    • 제20권4호
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    • pp.637-643
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    • 2006
  • The bench-scale chlorine exposure study was performed to investigate the effect of pretreatment by free chlorine and monochloramine ($NH_2Cl$) on the performance of RO membranes made of polyamide (PA). Feed monochloramination at 2mg/L did not cause significant productivity loss compared to free chlorine. However, metal coagulants reacted with monochloramine, the PA membrane suffered from a gradual loss of membrane integrity by chlorine oxidation, which was characterized as a decrease in salt rejection. Especially, RO membranes exposed to alum coagulants with monochloramine revealed the salt rejection lower than those exposed to iron coagulants. XPS membrane surface analysis demonstrated that the chlorine uptake on the membrane surface increased and carbon peaks were shifted significantly when exposed to alum coagulants with monochloramine.

관로 내 적정소독능 확보를 위한 재염소 기법의 적용 (Application of Rechlorination for Adequate Disinfection Ability in Water Distribution System)

  • 이두진;김영일;이종민;정남정;김용운
    • 상하수도학회지
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    • 제20권5호
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    • pp.701-707
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    • 2006
  • Disinfectant residual should be maintained to achieve biological stability during distribution of treated water. The wide distribution of retention times associated with storage and transport of water in a network and the reactivity of disinfectants make it difficult to maintain adequate residuals at critical locations. Rechlorination at some intermediate locations may reduce the total disinfectant dose while keeping residuals within specified limits throughout the water distribution system. In order to select the adequate location of rechlorination for achieving to maintain of residual chlorine throughout the distribution system, EPANET was used in this study. EPANET was well predicted chlorine transport and residual loss in the distribution system. Location of rechlorination was selected to maintain 0.4mg/L of residual chlorine throughout a water distribution system by field investigation and model simulation. The quantity of chlorine may reduced 36.7% and provided smooth residual between 0.42 and 0.60mg/L, when rechlorination would be used continuously at strategic location within the distribution system.

극전환 전해 반응기를 이용한 양식 폐수 내 암모니아 제거 (Removal of Ammonia in Aquaculture Wastewater by Electrolysis with Switching Poles)

  • 강기문;김아람;원용선;이제근;임준혁
    • 청정기술
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    • 제21권1호
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    • pp.45-52
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    • 2015
  • 본 연구에서는 양식 폐수 중 암모니아를 제거하는 전기분해 공정에 극전환을 도입하여 전극 표면에 불용성 금속화합물이 형성되는 오염 현상을 방지하고자 하였다. 한편 극전환으로 인한 전류 손실이 유리염소 이온의 생성에 미치는 영향을 파악함으로서 최적의 극전환 주기를 찾고자 하였다. 먼저 극전환 주기가 짧아지면서 전류손실로 인해 유리염소 이온의 형성 효율이 떨어지는 것을 확인하였으며 이는 암모니아 제거 효율이 감소함을 의미한다. 이에 극전환 주기에 따른 폐수 중의 칼슘과 마그네슘의 농도를 측정해 본 결과 극전환 주기를 60초 이하로 유지하면 극전환에 의한 불용성 금속화합물의 분해를 통해 전극 표면의 오염 현상을 충분한 수준에서 방지할 수 있음을 확인하였다. 따라서 높은 유리염소 이온의 생성효율 유지와 전극 오염 방지라는 두 가지 운전목적 사이에서 최적의 극전환 주기는 60초이었다.

Effect of film liner packaging with chlorine dioxide on the storage quality of containergrown or bare-root seedlings at cold or frozen temperatures in sawtooth oak and Japanese larch

  • Yu-Rim, Kim;Min-Seok, Cho;Byung-Bae, Park;Jong-Pil, Chun
    • 농업과학연구
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    • 제48권4호
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    • pp.753-760
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    • 2021
  • This study was carried out to discover suitable packaging methods during the cold or frozen storage of sawtooth oak and Japanese larch seedlings, which are major afforestation tree species in Korea. The weight loss rate of sawtooth oak was lower under frozen storage at -2℃ (maximum, 33.7%) than under cold storage at 2℃ (maximum, 61.0%). A film liner treatment inside the packaging box effectively suppressed the increase in the weight loss rate. For the sawtooth oak containerized seedlings, when stored at -2℃, the rate of weight loss was 17.9 to 25.4% in the untreated group and less than 1% in the film liner treatment group. Similar results were observed with Japanese larch. After two months of freezing at -2℃, both species maintained a low index of 1.0 - 1.1 with regard to the degree of shoot desiccation of containerized seedlings, and there was no significant difference between the treatments. On the other hand, the chlorine dioxide treatment could more effectively reduce the occurrence of mold and shoot desiccation than a PE single treatment in bare-root seedlings. According to these results, it was concluded that frozen storage is generally suitable as a means of long-term storage compared to cold storage of sawtooth oak and Japanese larch. A chlorine dioxide treatment at 20 ppm was effective for maintaining seedling quality levels during storage, demonstrating the good effect of suppressing the occurrence of shoot desiccation and the occurrence of mold.

저장 중 이산화염소 가스의 처리 조건에 따른 방울토마토의 품질변화 (Quality Changes of Cherry Tomato with Different Chlorine Dioxide ($ClO_2$) Gas Treatments during Storage)

  • 최우석;안병준;김영식;강호민;이정수;이윤석
    • 한국포장학회지
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    • 제19권1호
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    • pp.17-27
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    • 2013
  • 5와 $23^{\circ}C$의 저장 조건에서 이산화염소 가스 처리 방법에 따른 방울토마토의 품질 변화를 용기 내 기체조성, 중량감소율, 경도, 당성분, pH, 색도, 총균수로 평가하였다. 이산화염소 가스 처리방법은 고농도 단시간 전처리 I(5 ppm, 10분) 및 전처리 II(10 ppm, 3분)과 저농도 지속적인 처리(1 ppm, 매일 1번 처리)를 하여 이산화염소 가스 무처리군과 비교 실험하였다. 방울토마토에 이산화염소 가스 처리를 하였을 경우 방울토마토의 호흡률, 총균수, 부패율을 낮춰주고 경도와 당성분 함량을 유지시키는 효과가 있었지만 이산화염소 가스의 처리는 방울토마토의 pH와 색도에 영향을 미치지 않았다. 또한 이산화염소 가스 처리 방법에서도 이산화염소 가스 고농도 단시간 전처리 방법들(I, II)보다 저농도 이산화염소 가스의 지속적인 처리가 방울토마토의 호흡률, 총균수, 부패율, 경도, 당성분 함량 관찰에서 품질 유지에 더욱 영향을 미치는 것으로 나타났다. 따라서 '유니콘' 방울토마토는 저농도 지속적인 이산화염소 가스 처리가 전체적으로 유통기한 연장에 큰 효과를 보였으며, 이러한 결과를 토대로 유통기간 중 저농도의 이산화염소 가스를 지속적으로 방출하는 포장 시스템을 고려하여 적용할 경우 수출용 토마토의 선도유지에 충분히 기여할 것으로 판단된다.

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pH와 첨가제에 의한 이산화염소의 분해율 및 펄프 표백효과(2)-첨가제가 chlorate 생성량의 감소와 펄프 표백 효과에 미치는 영향 (Pulp Bleaching Effect and Ionization Rate of Chlorine Dioxide by Additive and Various pH Conditions (II))

  • 윤병호;왕립군
    • 펄프종이기술
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    • 제31권4호
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    • pp.49-57
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    • 1999
  • In CLO2 delignification and bleaching process, formation of chlorate corresponds to a loss of 20-36% of the original CKO2 charge. Because chlorate is inactive and harmful to environmental, it will be of benefit to find methods that can reduce the formation of chlorate during chlorine dioxide bleaching. Chlorate is mainly formed by the reaction HCIO +ClO2 $\longrightarrow$H+ + Cl_ +ClO3-2 On the other hand, AOX in chlorine dioxide bleacing is formed also due to the in-situ produced hypochlorous acid. THus both AOX and chlorate could be reduced by addition of hypochlorous acid. Some paper son the reduction of AOX by additives appeared , but systematic data on chlorate reduction as well as pulp and effluent properties are not available. THus this paper of focused on the effects on the reduction of chlorate and chlorine dioxide bleachability. The additives, fulfamic a챵, AMSO, hydrogen peroxide, oxalic acid were found to eliminate chlorine selectively in chlorine and chlorine dioxide mixture.However, when they were added to bleaching process, sulfamic acid and DMSO showed significant reduction of chlorate formation but hydrogen peroxide and oxalic aicd did not, and significant amount ofhydrogen peroxide was found resided in the bleaching effluent , In addition, sulfamic acid and DMSO decreased the bleaching end ph values while hydrogen peroxide and oxalic acid did not, which also indicated that hydrogen peroxide and oxalic acid were ineffective. The difference might be ascribed to the competitives of hypochlorous acid with lignin, chlorite (CKO2) and additives. Sulfamic acid and DMSO showed better pulpbrightness development but less alkaline extraction efficiency than hydrogen peroxide , oxalic acid and control, which means that insitu hypochlorous acid contributes to the formation of new chromophore structures that can be easily eliminated by alkaline extraction. DMSO decreased the delignification ability of chlorine dioxide due to the elimination of hypochlorous acid, but sfulfamic acid did to because the chlroinated sulfamic acid had stable bleachability. In addition, sulfamic acid, and SMSO shwed decreased color and COD of bleaching effluents, hydrogen peroxide decreased effluent color but not COD content, and oxalic acid had no statistically significant effects. No significant decreases of pulp viocosity were found except for hydrogen peroxide. Based on our results , we suggest that the effectiveness of hydrogen peroxide on the reduction of AOX in literature might be explained by other mechanisms not due to the elimination of hypochlorous acid , but to the direct decomposition of AOX by hydrogen peroxide.

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A Case Study of Ionic Components in the Size-resolved Ambient Particles Collected Near the Volcanic Crater of Sakurajima, Japan

  • Ma, Chang-Jin;Kim, Ki-Hyun;Kang, Gong-Unn
    • Asian Journal of Atmospheric Environment
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    • 제4권2호
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    • pp.72-79
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    • 2010
  • In this study, the ionic composition of volcanogenically derived particles and their temporal and spatial distributions have been investigated to evaluate the impact of the volcanic eruption on the local ecosystem and residents. To this end, an intensive field study was conducted to measure the size-segregated particulate matters at the east part of Sakurajima in Japan. Fractionated sampling of particles into > $PM_{10}$, $PM_{10-2.5}$, and $PM_{2.5}$ was made by a multi nozzle cascade impactor (MCI). The concentration of various ions present in the size-resolved particles was determined by Ion chromatography. The time dependent 3-dimensional Volcanic Ash Forecast Transport And Dispersion (VAFTAD) model developed by the NOAA Air Resources Laboratory (ARL) indicated that the sampling site of this work was affected by the volcanic aerosol particles plume. The temporal distributions of sulfate and $PM_{2.5}$ during the field campaign were significantly variable with important contributions to particle mass concentration. The chlorine loss, suspected to be caused by acidic components of volcanic gases, occurred predominantly in fine particles smaller than $10\;{\mu}m$.

Aqueous Chlorine Dioxide Treatment Improves the Shelf Life of Panax ginseng C.A. Meyer

  • Chun, Ho-Hyun;Song, Kyung-Bin
    • Preventive Nutrition and Food Science
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    • 제12권4호
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    • pp.284-288
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    • 2007
  • Effect of aqueous chlorine dioxide $(ClO_2)$ treatment on the quality change of fresh ginseng during storage was examined. Fresh ginseng samples were treated with 0, 50, and 100 ppm of $ClO_2$ solution, respectively, and stored at $4^{\circ}C$. Microbiological data of the fresh ginseng after $ClO_2$ treatment revealed that the populations of total aerobic bacteria, and yeast and mold were significantly reduced with the increase of $ClO_2$ concentration. In particular, the populations of total aerobic bacteria, and yeast and mold in the fresh ginseng decreased by 2.1 and 1.2 log CFU/g at 100 ppm $ClO_2$ treatment, respectively. Aqueous $ClO_2$ treatment improved the color of the fresh ginseng during storage, but there was no significant difference in weight loss during storage among treatments. Sensory evaluation results represented that the qualities of the fresh ginseng treated with aqueous $ClO_2$ during storage were better than those of the control. These results clearly indicate that aqueous $ClO_2$ treatment could be useful in decreasing the microbial growth and extending the shelf life of fresh ginseng.

수돗물 부식성 제어를 통한 수도관 부식방지 : 부식억제제별 효과와 영향에 대한 분석 (Corrosion Control in Water Pipes by Adjusting the Corrosivity of Drinking Water : Effect and impact of the Corrosion Inhibitor)

  • 박영복;박주현;박은희;이진숙;김현돈;최영준;정현미;허유정;최인철
    • Corrosion Science and Technology
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    • 제15권6호
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    • pp.303-310
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    • 2016
  • The tap water used in Seoul was found to be corrosive. Its corrosivity was effectively reduced by that the additions of alkali agent such as NaOH, $Ca(OH)_2$ and corrosion inhibitor such as $H_3PO_4$. For the corrosion test, carbon steel pipe 50 m long was exposed to the drinking water produced by a pilot plant at $36.5^{\circ}C$, similar to the existing process where it takes about 20 minutes to reduce the initial chlorine content of 0.5 mg/L to 0.05 mg/L. $CO_2$ and $Ca(OH)_2$ was added not only to control the Langelier index (LI) above -1.0 and but also, to increase the duration time of residual chlorine by about 6 times. The persistence effect of residual chlorine was in the order of $H_3PO_4$ > $Ca(OH)_2$ > NaOH. Measurements of weight loss showed that corrosion inhibition was effective in order of $Ca(OH)_2$ > $H_3PO_4$ > NaOH > no addition, where the concentrations of $Ca(OH)_2$ and phosphate were 5 ~ 10 mg/L (as $Ca^{2+}$) and 1 mg/L (as $PO{_4}^{3-}$), respectively.

Reflection on Kinetic Models to the Chlorine Disinfection for Drinking Water Production

  • Lee, Yoon-Jin;Nam, Sang-ho
    • Journal of Microbiology
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    • 제40권2호
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    • pp.119-124
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    • 2002
  • Experiments for the characterization of inactivation were performed in a series of batch processes with the total coliform used as a general indicator organism based on the chlorine residuals as a disinfectant. The water samples were taken from the outlet of a settling basin in a conventional surface water treat- ment system that is provided with the raw water drawn from the mid-stream of the Han River, The inactivation of total coliform was experimentally analysed for the dose of disinfectants contact time, filtration and mixing intensity. The curves obtained from a series of batch processes were shaped with a general tailing-off and biphasic mode of inactivation, i.e. a sharp loss of bacterial viability within 15 min followed by an extended phase. In order to observe the effect of carry-over suspended solids on chlorine consumption and disinfection efficiency, the water samples were filtered, prior to inoculation with coliforms, with membranes of both 2.5$\mu$m and 11.0 $\mu$m pore size, and with a sand tilter of 1.0 mm in effective size and of 1.4 in uniformity coefficient. As far as the disinfection efficiency is concerned, there were no significant differences. The parameters estimated by the models of Chick-Wat-son, Hom and Selleck from our experimental data obtained within 120 min are: log(N/N$\_$0/)=-0.16CT with n=1, leg(N/N$\_$0/)=-0.71C$\^$0.87/ with n 1 for the Chick-Watson model, log (N/N$\_$0/)=-1.87C$\^$0.47/ T$\^$0.36/ for the Hom model, log (MHo)=-2.13log (1+CT/0.11) for the Selleck model. It is notable that among the models reviewed with regard to the experimental data obtained, the Selleck model appeared to most closely resemble the total coliform survival curve.