• Title/Summary/Keyword: Drinking, Residual

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Characteristics of Bacterial Communities in Biological Filters of Full-Scale Drinking Water Treatment Plants

  • Choi, Yonkyu;Cha, Yeongseop;Kim, Bogsoon
    • Journal of Microbiology and Biotechnology
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    • v.29 no.1
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    • pp.91-104
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    • 2019
  • The taxonomic and functional characteristics of bacterial communities in the pre-chlorinated rapid filters and ozonated biological activated carbon (BAC) filters were compared using Illumina MiSeq sequencing of the 16S rRNA gene and community-level physiological profiling (CLPP) based on sole-carbon-source utilization patterns. Both the rapid filters and BAC filters were dominated by Rhizobiales within ${\alpha}-proteobacteria$, but other abundant orders and genera were significantly different in both types of filter. Firmicutes were abundant only in the intermediate chlorinated rapid filter, while Acidobacteria were abundant only in the BAC filters. Bacterial communities in the rapid filter showed high utilization of carbohydrates, while those in the BAC filters showed high utilization of polymers and carboxylic acids. These different characteristics of the bacterial communities could be related to the different substrates in the influents, filling materials, and residual disinfectants. Chlorination and ozonation inactivated the existing bacteria in the influent and formed different bacterial communities, which could be resistant to the oxidants and effectively utilize different substrates produced by the oxidant, including Phreatobacter in the rapid filters and Hyphomicrobium in the BAC filters. Bradyrhizobium and Leptothrix, which could utilize compounds adsorbed on the GAC, were abundant in the BAC filters. Ozonation increased taxonomic diversity but decreased functional diversity of the bacterial communities in the BAC filters. This study provides some new insights into the effects of oxidation processes and filling materials on the bacterial community structure in the biological filters of drinking water treatment plants.

Geochemical evaluation of groundwater quality of Peshawar Basin, Pakistan

  • Akhter, Gulraiz;Mand, Bilal A.;Shah, Munir H.
    • Advances in environmental research
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    • v.10 no.1
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    • pp.43-57
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    • 2021
  • Evaluation of groundwater quality is vital due to its diverse use for several purposes. In the present study, groundwater quality and suitability from the Peshawar basin, Pakistan, were evaluated for drinking and irrigation purposes. The water samples were analysed for major cations (Ca, Mg, Na and K) and anions (chloride, bicarbonate and sulphate) along with other physicochemical parameters (pH, electrical conductivity, total dissolved solids, and total hardness). About 95% of the water samples were found to be within the WHO, US-EPA and Pak-EPA permissible levels for drinking purposes. Seventy percent (70%) of the water samples belonged to the hard water category. Irrigation water quality parameters, such as, chloride, residual sodium bicarbonate, sodium adsorption ratio, percent sodium, magnesium adsorption ratio, Kelly's ration and permeability index were evaluated which demonstrated that the groundwater was highly to moderately suitable for irrigation. A correlation study was conducted to find out the mutual associations among the variables. Piper diagram indicated the overall chemical nature of the study area was calcium-magnesium bicarbonate type. Cluster analysis revealed mutual apportionment of various parameters in the groundwater of the Peshawar basin, Pakistan.

A Case Study of Characterization of AOC Formation

  • Kim, Ji-Hoon;Hwang, Hyeon-Uk;Kim, Young-Ju
    • Journal of Environmental Science International
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    • v.19 no.3
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    • pp.261-267
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    • 2010
  • The variation of assimilable organic carbon(AOC) concentration at each condition of ozonation was investigated using a model water and drinking water resource. AOC concentration of model raw water and drinking water resource tended to increase at low ozone dose. The maximum AOC concentration was detected when the residual ozone begin to be measured. Also, the AOC concentration increase at pH 8 compared to both pH 6 and 7 while that for pH 9 decreased rapidly. The removal characteristics of trihalomethane formation potential(THMFP) by ozonation was also investigated. Unlike the trend of AOC, the THMFP concentration never increased by ozonation but decreased even at low ozone dosage. From these results, the ozone dosage would be effective to simultaneously decrease both AOC and THMFP.

Reuse of Rice-Hull and Application Technology Development in Waste Water Treatment (왕겨의 재활용 및 하수처리 활용기술 개발)

  • Shin, Ho-Sang;Ahn, Hye-Sil;Jung, Dong-Gyun
    • Proceedings of the Korean Institute of Resources Recycling Conference
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    • 2003.10a
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    • pp.170-173
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    • 2003
  • Activated Rice-Hull carbon was developed to remove ammonia compounds in water matrix. Isotherm adsorption tests of ammonia were conducted using a bottle-point technique and column test. Residual ammonia after Jar-Test or passing through the column was determined by Indophenol method, and assessed the removal efficiency for ammonia of the adsorbent. As a result, the adsorption capacity for ammonia of activated racehull carbon was very larger than that of coconut shell carbon, because the rice hull carbon had the higher BET surface area of silicate. The activated racehull carbon is under the development as adsorbent to remove ammonia in drinking water and waste water.

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Estimation of Fugitive Emission Factors of HFC-134a from Scrap Cold Drinking Vending Machine at Use- and Disposal-Phase (음료용 폐자동판매기에서의 HFC-134a 사용 및 폐기단계 탈루배출계수 결정에 대한 연구)

  • Lee, Youngphyo;Kim, Eui-Kun;Kim, Seungdo;Byun, Seokho;Kim, Hyerim;Park, Junho;Lee, Dongwon
    • Journal of Korean Society of Environmental Engineers
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    • v.35 no.5
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    • pp.350-355
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    • 2013
  • Little information is available for emission pathway even if HFC-134a that is known as one of the major greenhouse gases has been broadly used in Korea. This paper attempts to clarify the emission characteristics of HFC-134a used for refrigerant of cold drinking vending machines (CDVMs) at the use- and disposal-phase. We measured the residual amounts in the scrap CDVMs of 47 by applying commercial recover for refrigerant. The first-order kinetic model was introduced and the emission rate would be proportional to the remaining quantity of refrigerant. The emission factor at the use-phase was determined indirectly to be $6.9{\pm}0.7$ %/yr within a confidence interval of 95%, using information on residual amount and elapsed operation time at the disposal point. Correspondingly, the annual emission rate of HFC-134a per CDVM was determined to be 11.6 g. The average residual rate of HFC-134a in scrap CDVMs was assessed to be $62.5{\pm}2.2%$, leading to a potential emission amount of 144.8 g per scrap CDVM. The chemical compositions of refrigerants from scrap passenger vehicles are quite similar to those of new refrigerants, suggesting that the refrigerants from scrap passenger vehicles could be reused. During the recovering process of refrigerant, the recovered refrigerant was contaminated by compressor lubricant that accounted for about 30% in weight. It is necessary to separate the refrigerant from the recovered material contaminated by lubricant for recycling and reuse the refrigerant.

Optimization of Synthesis Condition and Determination of Residue for Polyamine Type Flocculant (폴리아민계 고분자 응집제의 합성조건 최적화 및 잔류물분석)

  • Choi, Soo-Young;Park, Lee-Soon;Im, Sung-Hyun;Ryoo, Jae-Jeong;Choi, Sang-June;Hwang, Won-Joo
    • Applied Chemistry for Engineering
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    • v.9 no.7
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    • pp.1043-1046
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    • 1998
  • Aluminium based inorganic flocculants are extensively used in this country in the removal of fine particles present in the raw water for the production of drinking water. These inorganic flocculants, however, have potential hazard of high residual aluminium ions in the treated waters, which is known to be one of the reasons of alzheimer's disease. Inorganic flocculants alone are sometimes incapable of treating water when there are excessive turbidity in the raw water sources due to flooding. A polyamine type polymeric flocculant has long been used to treat raw water in the drinking water production in the European countries and United State of America. The optimum reaction conditions such as mole ratio of epichlorohydrin(EPI) to dimethylamine(DMA), reaction temperature and time for each stage for the pilot scale preparation of polyamine from EPI-DMA was studied in this work. The variation of intrinsic viscosity and flocculating efficiency in the water treatment of the synthesized polyamines were evaluated. The residual materials after polymerization reaction were analyzed by gas chromatography to study the effect of variation of reaction conditions.

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Physico-chemical and Microbiological Analysis of Tap Water in the Apartment in Taegu City (대규모 음용수 저장시설의 수질평가)

  • Kim, Seck-Bhum;Kang, Pock-Soo;Chung, Jong-Hak
    • Journal of Yeungnam Medical Science
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    • v.5 no.1
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    • pp.69-75
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    • 1988
  • The drinking water in the apartment is stored in reservior tank and thereafter supplied each household. In case the drinking water is stored too long or insanitary, tap water might change in quality. This study was carried out to evaluate the physico-chemical and microbiological conditions of 36 samples of tap water of apartments compared to 18 samples of tap water of independence houses in Taegu City from May to October, 1987. Main findings are summarized as follows : PH values were within normal range in all samples. Samples less than 0.2ppm in residual chlorine accounted for 16.7% in the appartment and 5.6% in the independence house. Nitrite nitrogen was detected 2.8% of apartment samples only. Among the total of 54 samples, 11.1% of the apartment and independence samples were over the normal value in standard plate count. Samples more than 1.8 of most probable number(MPN) accounted for 27.8% in the apartment and 33.3% in the independence house. In result of test for residual chlorine, nitrite nitrogen, standard plate count, and MPN, the proportion of the samples revealed inappropriated in respect of drinking water standards. In case of all sorts of tests was 2.7% in apartment and nothing in independence houses, in case of 3 sorts of tests was 2.7% in apartment and 5.6% in independence houses, in case of 2 sorts of tests was 8.3% in apartment and 5.6% in independence houses, and in case of only 1 test was 25.0% in apartment and 22.2% in independence houses. Correlation between residual chlorine and standard plate count, and between standard plate count and MPN were observed. It was found that the more years since construction of apartment were, the worse tap water was in quality.

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Masking Effect of Chlorine on Algae-related Taste and Odor in Drinking Water Supplies (염소의 상수원 내 조류 이취미 Masking 효과)

  • Kim, Young-il;Lee, Yu-Jeong;Shin, Heung-Sup;Bae, Byung-Uk
    • Journal of Korean Society of Water and Wastewater
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    • v.22 no.2
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    • pp.227-232
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    • 2008
  • The masking effect of chlorine on algae-related taste and odor(T&O) compounds has long been an important issue for water suppliers. In this study, masking experiments with chlorine were performed on two kinds of treated water and one of raw water. After adding chlorine(0 to 0.8 mg/L) to water samples, odor intensity was evaluated by a newly developed sensory method(2-out-of-5 odor test) for three days along with the measurement of residual chlorine concentration. Even though the relationship between the residual chlorine concentration and odor reported by the sensory analysts was not always coincident, it was proved that residual chlorine more than a certain concentration could completely mask both added geosmin and naturally occurring T&O compounds. For the sand-filtered water spiked with 10 ng/L of geosmin, 0.12-0.18 mg/L of residual chlorine was necessary to achieve complete masking. In the case of GAC-filtered water, 10 ng/L of spiked geosmin was completely masked by 0.15-0.1 mg/L of residual chlorine. Combined ozone and GAC was not enough to treat raw water spiked with 300 ng/L of geosmin. In this experiment, sensory analysts were able to detect earthy or musty odors from the treated water. From a masking experiment with raw water taken from the Daechung Reservoir, it was found that fishy odor was more difficult to mask with chlorine than earthy odor. As the chlorine residual declined, the analysts began to notice the original odor and the fishy odor was noticed earlier than the earthy odor.

A Review Study on Major Factors Influencing Chlorine Disappearances in Water Storage Tanks (저수조 내 잔류염소 감소에 미치는 주요 영향 인자에 관한 문헌연구)

  • Noh, Yoorae;Kim, Sang-Hyo;Choi, Sung-Uk;Park, Joonhong
    • Journal of Korean Society of Disaster and Security
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    • v.9 no.2
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    • pp.63-75
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    • 2016
  • For safe water supply, residual chlorine has to be maintained in tap-water above a certain level from drinking water treatment plants to the final tap-water end-point. However, according to the current literature, approximately 30-60% of residual chlorine is being lost during the whole water supply pathways. The losses of residual chlorine may have been attributed to the current tendency for water supply managers to reduce chlorine dosage in drinking water treatment plants, aqueous phase decomposition of residual chlorine in supply pipes, accelerated chlorine decomposition at a high temperature during summer, leakage or losses of residual chlorine from old water supply pipes, and disappearances of residual chlorine in water storage tanks. Because of these, it is difficult to rule out the possibility that residual chlorine concentrations become lower than a regulatory level. In addition, it is concerned that the regulatory satisfaction of residual chlorine in water storage tanks can not always be guaranteed by using the current design method in which only storage capacity and/or hydraulic retention time are simply used as design factors, without considering other physico-chemical processes involved in chlorine disappearances in water storage tank. To circumvent the limitations of the current design method, mathematical models for aqueous chlorine decomposition, sorption of chlorine into wall surface, and mass-transfer into air-phase via evaporation were selected from literature, and residual chlorine reduction behavior in water storage tanks was numerically simulated. The model simulation revealed that the major factors influencing residual chlorine disappearances in water storage tanks are the water quality (organic pollutant concentration) of tap-water entering into a storage tank, the hydraulic dispersion developed by inflow of tap-water into a water storage tank, and sorption capacity onto the wall of a water storage tank. The findings from his work provide useful information in developing novel design and technology for minimizing residual chlorine disappearances in water storage tanks.

A Study on the Ozone Consumption Rate for Drinking Water Treatment Process with Ozone Application (오존의 정수처리 적용을 위한 오존소비인자에 관한 연구)

  • Kang, Tae-Hee;Oh, Byung-Soo;Kwon, Soon-Buhm;Sohn, Byeong-Yong;Kang, Joon-Wun
    • Journal of Korean Society of Environmental Engineers
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    • v.27 no.6
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    • pp.663-669
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    • 2005
  • The aim of this study was to investigate the ozone decay pattern for the effective application of ozone in drinking water treatment. In order to measure the ozone decomposition in water, ozone measuring instrument was developed with flow injection analysis (FIA) method. From the result of continuous residual ozone concentration in water, it was confirmed that the ozone decay pattern was divided with instantaneous ozone demand(I.D) and pseudo first-order rate($k_c$) phases, which were influenced by the variation of ozone dose. The empirical model obtained from I.D and $k_c$ values enabled us to predict the residual ozone concentration according to the reaction time, showing the high correlation between model and experimental values. The concentration of OH radical and $R__{ct}$ could be indirectly measured by OH radical probe compound. In both I.D and $k_c$ phases, the production pattern of OH radical could be observed, which was also affected by the variation of ozone dose. Finally, it was confirmed that the ozone consumption rate was varied according to the each drinking water treatment process and seasoning. Therefore, the optimum position and dosage of ozone have to be selected by considering various factors.