• Title, Summary, Keyword: COD reduction

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Production and Characterization of Extracellular Polysaccharide Produced by Pseudomonas sp. GP32 (Pseudomonas sp. GP32에 의해 생산된 세포 외 다당류의 생산 및 특성)

  • Lee, Myoung Eun;Lee, Hyun Don;Suh, Hyun-Hyo
    • Journal of Life Science
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    • v.25 no.9
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    • pp.1027-1035
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    • 2015
  • A strain GP32 which produces a highly viscous extracellular polysaccharide was conducted with soil samples and identified as Pseudomonas species. The culture flask conditions for the production of extracellular polysaccharide by Pseudomonas sp. GP32 were investigated. The most suitable carbon and nitrogen source for extracellular polysaccharide production were galactose and (NH4)2SO4. The optimum carbon/nitrogen ratio for the production of extracellular polysaccharide was around 50. The optimum pH and temperature for extracellular polysaccharide production was 7.5 and 32℃, respectively. In batch fermentation using a jar fermentor, the highest extracellular polysaccharide content (15.7 g/l) was obtained after 70 hr of cultivation. The extracellular polysaccharide produced by Pseudomonas sp. GP32 (designated Biopol32) was purified by ethanol precipitation, cetylpyridinium chloride (CPC) precipitation, and gel permeation chromatography. Biopol32, which has an estimated molecular weight of over 3×107 datons, is a novel polysaccharide derived from sugar components consisting of galactose, glucose, gulcouronic acid and galactouronic acid in an approximate molar ratio of 1.85 : 3.24 : 1.00 : 1.42. The solution of Biopol32 showed non-Newtonian characteristics. The viscosity of Biopol32 exhibited appeared to be higher at all concentration compared to that of zooglan from Zoogloea ramigera. An analysis of the flocculating efficiency of Biopol32 in industry wastewater (food, textile, and paper wastewater) revealed chemical oxygen demand (COD) reduction rates 58.4-67.3% and suspended solid (SS) removal rates 82.6-91.3%. Based on these results, Biopol32 is a possible candidate for industrial applications such as wastewater treatment.

Characteristics of Stormwater Treatment in Construction Site (건설 현장 내 비점오염원 처리 특성 평가)

  • Choi, Younghoa;Kim, Changryong;Kim, Hyosang;Oh, Jihyun;Jeong, Soelhwa
    • Journal of the Korean Geoenvironmental Society
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    • v.11 no.6
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    • pp.69-75
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    • 2010
  • Total suspendid solid (TSS) of non point source pollutants in construction site are in higher concentration than others (BOD, COD etc). Also, the TSS concentration is very sensitive to the rainfall intensity in early stage of construction. There are two methods for treatment of non point source pollutants, which are temporary treatment facility and filtering one. But they have disadvantages. Temporary facility system has very low efficiency and filtering system consumes high energy and takes up large footprint. This study shows how prefabricated flocculation/coagulation system is developped to cover the above weakness and evaluation of the system performance in construction site. The prefabricated flocculation/coagulation system has very high treatment efficiency comparing with temporary and filtering system and takes small footprint. Therefore, it expects that the system leads to prevention of pollution near construction site and reduction of public grievance. Proper coagulant dosage and sludge circulation facility application, controlling the height of sludge interfacial are necessary to maximize the system efficiency.

Characteristics of Particle Composition and Organic Matter Distribution for Tidal Flat Sediments in the Saemankeum Area (새만금 갯벌의 입도조성과 유기물질 분포특성)

  • YOU Sun-Jae;KIM Jong-Gu;CHO Eun-Il
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.36 no.1
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    • pp.49-54
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    • 2003
  • This study was conducted to evaluate characteristics of particle composition and organic matter distribution for tidal flat sediments in the Saemankeum area. The tidal flat sediments consist of predominantly sand and a little of silt, whereas the content of clay was very low. The analyzed values of particles of tidal flat sediments were in the range of $4.60\~10.90\;{\phi}$ for mean size and $-0.1\~1.75\;{\phi}$ for sorting and $-1.0\~0.92\;{\phi}$ for skewness and $0.27\~6.75\;{\phi}$ for kurtosis. The tidal flat sediments are interpreted as representing significant effect of the environmental change due to the construction of Saemankeum embankment. The ORP was in the range of -133$\~$200 (mean 73) mV. But 24 stations of the total stations showed reduction condition, The concentration of CODs was in the range of 17.54$\~$6,176.3 mg/kg. The ratio of C/S was 0.02$\~$0.45 (mean 0.24). And the Saemankeum tidal flat sediment was a little effected by input organic pollutants from upper site area. Conclusively, conservation of the Saemankeum tidal flat sediment was requested because it is for the growing fishery and low organic matter.

Assessment of Permissible Inflow Load for Water Quality Management in Yeoja Bay, Korea (여자만의 수질관리를 위한 허용유입부하량 산정)

  • Kim, Hyung-Chul;Lee, Won-Chan;Kim, Jong-Gu;Hong, Sok-Jin;Kim, Kyoung-Mi;Cho, Yoon-Sik;Park, Sung-Eun;Kim, Jin-Ho
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.17 no.4
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    • pp.345-356
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    • 2011
  • Based on the consideration of land based pollutant discharges from the basin and seawater quality related carrying capacity and the seawater quality improvement in receiving water bodies of Yeoja Bay where eutrophication and organic pollution are in progress, were evaluated. The permissible inflow loads of BOD, TN and TP by using the geographical features and box modelling method were estimated. As results, it is shown that the reduction rate of discharged BOD and TP loads were 39.3% and 30.8 %, respectively, however, 6.9% was estimated for TN. According to the pollutant loading in each tributary and generated load of the basin, it is given much weight on the land use group, and also was shown in discharged load estimation. This suggests that it is important to control nonpoint source pollutant such as livestock and land use groups as well as point source to contribute the proposition of the water quality improvement plan according to the characteristics of the bay.

A Strategy for Improving the Sewerage Systems of Two Rural Areas in Gyeonggi Province (경기도의 2개 시.군 사례를 통한 농어촌지역 하수도 정비 추진 방안)

  • Moon, Chul-Hwan;Ahn, Ji-Hoon;Jang, Mi-Jeong;Lee, Sang-Hyup;Cho, Young-Moo;Kim, Yun-Je
    • Journal of Korean Society of Environmental Engineers
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    • v.32 no.6
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    • pp.563-580
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    • 2010
  • In 2009 the Korea Ministry of Environment announced 'A Comprehensive Plan for the Improvement of Sewer Service in Rural Area' aiming at reduction of the sewer service gap between urban and rural areas as well as improvement in the residential environment of the rural area. According to the plan, the sewer system supply rate for the rural area is expected to reach up to 75% until 2015 with the budget of 4.7 trillion won (Korean currency). It is not certain, however, that the increase in the sewer system supply rate will accompany improvement of water quality in receiving water because several veiled problems that can occur in small-scale sewer treatment plants are poorly addressed in the plan. In this study, those issues for the small-scale sewer treatment plants and their solutions were discussed based on a case study in which we investigated 19 treatment facilities at two rural regions in Gyeonggi province. This study also included strategies useful for the plan. From the results of investigation, some problems, e.g., high hourly variations but low in flowrates and low mass loading were commonly identified. Although operation parameters in sewer treatment plants require to be modified depending on the mass loading, most of the plants were operated with the initial design parameters which causes the decrease of removal efficiency. In the intensive diagnosis, we arranged and applied solutions (e.g., flow equalization, air on/off time control, etc) to the two selected plants and found out improvement of effluent water quality, especially organic matters (COD and SS) and T-N with better denitrification performance.

Concentration of metallic elements in surface sediments at a waste disposal site in the Yellow Sea (황해 폐기물 투기해역(서해병) 표층 퇴적물의 금속원소 분포)

  • Koh, Hyuk-Joon;Choi, Young-Chan;Park, Sung-Eun;Cha, Hyung-Kee;Chang, Dae-Soo;Lee, Chung-Il;Yoon, Han-Sam
    • Journal of Environmental Science International
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    • v.22 no.7
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    • pp.787-799
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    • 2013
  • The aim of this study was to investigate the accumulation of metallic elements and the control effect of marine pollution caused by ocean dumping in the sediments at a waste disposal area in the Yellow Sea. In July 2009, concentrations of organic matter and metallic elements (Al, Fe, As, Cd, Cr, Co, Hg, Ni, Mn, Pb, and Zn) were measured in surface sediments at the site. The ignition loss (IL) in the surface sediments showed a mean value of 15.4%, about 1.5 times higher than the mean value of the sediments in the coastal areas of Korea. The chemical oxygen demand (COD) at some disposal sites exceeded 20 mg $O_2/g{\cdot}dry$, which signifies the initial concentration of marine sediment pollutants in Japan. The disposal sites contain higher concentrations of Cr, Cu and Zn than the sediments of bays and estuaries that might be contaminated. The magnitude of both metal enrichment factors (EF) and adverse biological effects suggest that pollution with Cr and Ni occurred due to the dumping of waste in the study area. In addition, the geoaccumulation index (Igeo) showed that the surface sediments were moderately contaminated. By the mid-2000s, when the amount of waste dumped at this site was the highest, the concentration of metallic elements was higher than ever recorded. On the other hand, in 2008-09, the need for environmental management was relatively low compare with the peak. As a result, the quality of marine sediment has been enhanced, considering the effect of waste reduction and natural dilution in the disposal area.

Treatment of N, P of Auto-Thermal Thermophilic Aerobic Digestion Filtrate with Struvite Crystallization (Struvite 결정화 반응을 이용한 고온 소화 여과액의 N, P 처리 특성)

  • Choo, Yeon-Duk;Kim, Keum-Yong;Ryu, Hong-Duck;Lee, Sang-Ill
    • Journal of Korean Society of Environmental Engineers
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    • v.33 no.11
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    • pp.783-789
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    • 2011
  • Recently, auto-thermal thermophilic aerobic digestion (ATAD) has a great attention for destruction of wasted sludge biomass in wastewater treatment plant. Reduction of sludge concentration has been successfully achieved with pilot scale ATAD and ceramic filtration process in field condition. However, high concentration of COD, total nitrogen (TN) and total phosphorus (TP) was observed in filtrate, which should be treated before recirculation of filtrate to biological wastewater treatment plant. This study was focused on removal of nitrogen and phosphorus contained in the filtrate of ATAD, using struvite crystallization method. The effect of operational and environmental parameters (such as, N, P and Mg ion concentration and molar ratio, pH, reaction time, agitation strength, seed dosage, and reaction temperature) on the treatment of TN and TP with struvite crystallization were evaluated. Magnesium (as $MgCl_26H_2O$) and phosphorus (as $K_2HPO_4$) ions were, if necessary, added to increase nitrogen removal efficiency by the crystal formation. Average concentration of $NH_4^+-N$ and $PO_4^{3-}-P$ of the filtrate were 1716.5 mg/L and 325.5 mg/L, respectively. Relationship between removal efficiencies of nitrogen and phosphorus and molar ratios of $Mg^{2+}$ and $PO_4^{3-}-P$ to $NH_4^+-N$ was examined. Crystal formation and nitrogen removal efficiencies were significantly increased as increasing molar ratios of magnesium and phosphorus to nitrogen. As molar ratio of $Mg^{2+}:PO_4^{3-}-P:NH_4^+-N$ were maintained to 2 : 1 : 1 and 2 : 2 : 1, removal efficiencies of nitrogen and phosphorus were 71.6% and 99.9%, and 93.8% and 98.6%, respectively. However, the effect of reaction time, mixing intensity, seed dose and temperature on the struvite crystallization reaction was not significant, comparing to those of molar ratios. Settled sludge volume after struvite crystallization was observed to be reduced with increase of seed dose and to be increased at high temperature.