• Title/Summary/Keyword: COD(chemical oxygen demand)

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Treatment of Contaminated Groundwater Containing Petroleum and Suspended Solids Using DAF and Mixed Coagulation Processes (DAF와 혼화응집공정을 이용한 현탁성 고형물 함유 유류 오염 지하수 처리)

  • Lee, Chaeyoung;Jang, Yeongsu
    • Journal of the Korean GEO-environmental Society
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    • v.11 no.8
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    • pp.25-32
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    • 2010
  • Contamination of soil and groundwater by the compounds of hydrocarbon petroleum has been widely accepted as the main cause that harms the environments and health. To remove those pollutants, absorbing clothes, activated carbons, or oil-water separation devices with the gravity method are employed for treatment. However, those materials and devices cannot remove the emulsion pollutants despite of their efficiency for removing free products. Therefore, we investigated the problems which occur during the groundwater treatment for the highly concentrated suspended solid particles, which can be resulted from excavation, and to propose methods to remove TPH(Total Petroleum Hydrocarbon). After coagulation experiment with high molecular polymers, the concentration of SS(Suspended Solids) and COD(Chemical Oxygen Demand) turned to satisfy the groundwater quality criteria within 5 minutes while the concentration of TPH failed to meet the water quality standard of effluent. Consequently, the water quality criteria for effluent could not be met by single DAF(Dissolved Air Flotation) process. However all water quality criteria could be satisfied after 20 minutes when coagulation reactions are carried out simultaneously in the DAF reactor.

Treatment of Oil Contaminated Groundwater Using DAF and Fenton Oxidation Process (DAF와 펜톤 산화 공정을 이용한 유류 오염 지하수 처리)

  • Lee, Chaeyoung
    • Journal of the Korean GEO-environmental Society
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    • v.11 no.10
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    • pp.49-55
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    • 2010
  • The oil spill occurred frequently due to probably the increased consumption of oil as the energy source and the raw materials of various chemicals. For the treatment of oil contaminated groundwater, DAF(Dissolved Air Flotation) is being used but the removal efficiency is low. Therefore it is necessary to reduce the free phase oil, oil-in water type or water-in oil type emulsified oil, and soluble oil which are the main sources of contaminated groundwater. In this study, treatment of contaminated groundwater was performed using the Fenton oxidation process. The optimum conditions for the removal of THP(Total Petroleum Hydrocarbon) were 3 of pH, 25mM of $H_2O_2$ concentration and 25mM of $Fe^{2+}$ concentration. THP and COD(Chemical Oxygen Demand) concentrations decreased less than 1.5mg/L and 40.0mg/L in 7 minutes using DAF and Fenton oxidation process. However it is necessary to install the settling basin as the sludge concentration increased approximately 5 times.

A study of Swine Wastewater Treatment using Photosynthetic Bacteria (광합성 세균을 이용한 돈분 폐수 처리에 관한 연구)

  • Choi, Kyung-Min;Park, Eung-Roh;Ju, Hong-Shin;Yang, Jae-Kyung;Lee, Ki-Young;Lee, Sung-Taik;Lee, Mu-Choon
    • Journal of the Korea Organic Resources Recycling Association
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    • v.4 no.2
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    • pp.11-17
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    • 1996
  • Photosynthetic bacteria, strains KN 1-1, KN 2-1 and KN 2-3 were isolated from nature, and were studied for swine wastewater treatment. Growth of those photosynthetic bacteria were increased to 2~3 fold in organic-acid added medium(sodium acetate 1g, sodium propionate 1g and sodium butyrate 1g in Lascelles basal medium $1{\ell}$) than cultivation in Lascelles basal medium, and amount of bacteriochlorophyll a were increased to 1.5~2 fold. Chemical Oxygen Demand(COD) in swine wastewater using photosynthetic bacteria, strains KN 1-1, KN 2-1 and KN 2-3 were reduced 80%, 89% and 75%, respectively.

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Electricity Generation from Dairy Wastewater Using Microbial Fuel Cell (미생물연료전지를 이용한 유가공 폐수로부터 전기생산)

  • Roh, Sung-Hee;Lee, Sung-Wook;Kim, Kyung-Ryang;Kim, Sun-Il
    • Applied Chemistry for Engineering
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    • v.23 no.3
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    • pp.297-301
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    • 2012
  • Microbial fuel cell (MFC) is the major of bio-electrochemical system which can convert biomass spontaneously into electricity through the metabolic activity of the microorganisms. In this study, we used an activated sludge as a microbial inoculum and then investigated the feasibility of using dairy wastewater as a possible substrate for generating electricity in MFC. To examine the performance of MFC as power generator, the characteristics on cell potentials, power density, cyclic voltammetric analysis and sustainable power estimation were evaluated for dairy wastewater. The maximum power density of $40\;mW/m^2$was achieved when the dairy wastewater containing 2650 mg/L COD was used, leading to the removal of 88% of the COD. The results from this study demonstrate the feasibility of using MFC technology to generate electricity while simultaneously treating dairy wastewater effectively.

Integrated Wet Oxidation and Aerobic Biological Treatment of the Wastewater Containing High Concentration of Phenol (고농도 페놀 폐수의 습식산화와 호기성 생물학적 통합처리)

  • Choi, Ho-Jun;Lee, Seung-Ho;Yu, Yong-Ho;Yoon, Wang-Lai;Suh, II-Soon
    • KSBB Journal
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    • v.22 no.4
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    • pp.244-248
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    • 2007
  • The treatment of a model wastewater containing high concentration, 10 $g/{\ell}$, of phenol in an integrated wet oxidation-aerobic biological treatment was investigated. Partial wet oxidation under mild operating conditions was capable of converting the original phenol to biodegradable organic acids such as maleic acid, formic acid and acetic acid, the solution of which was subjected to the subsequent aerobic biological treatment. The wet oxidation was carried out at 150$^{\circ}C$ and 200$^{\circ}C$ and the initial pH of 1 to 12. The high temperature of 200$^{\circ}C$ and the acidic initial condition in the wet oxidation led to effluents of which biodegradability was higher in the subsequent biological oxidation process, as assessed by chemical oxygen demand (COD) removal. Homogeneous catalyst of $CuSO_4$ was also used for increasing the oxidation rate in the wet oxidation at 150$^{\circ}C$ and initial pH of 3.0. However, the pretreatment with the catalytic wet oxidation resulted in effluents which were less biodegradable in the aerobic biological process compared to those out of the non-catalytic wet oxidation at the same operating conditions.

Effect of Algal Inoculation on COD and Nitrogen Removal, and Indigenous Bacterial Dynamics in Municipal Wastewater

  • Lee, Jangho;Lee, Jaejin;Shukla, Sudheer Kumar;Park, Joonhong;Lee, Tae Kwon
    • Journal of Microbiology and Biotechnology
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    • v.26 no.5
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    • pp.900-908
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    • 2016
  • The effects of algal inoculation on chemical oxygen demand (COD) and total nitrogen (TN) removal, and indigenous bacterial dynamics were investigated in municipal wastewater. Experiments were conducted with municipal wastewater inoculated with either Chlorella vulgaris AG10032, Selenastrum gracile UTEX 325, or Scenedesmus quadricauda AG 10308. C. vulgaris and S. gracile as fast growing algae in municipal wastewater, performed high COD and TN removal in contrast to Sc. quadricauda. The indigenous bacterial dynamics revealed by 16S rRNA gene amplification showed different bacterial shifts in response to different algal inoculations. The dominant bacterial genera of either algal case were characterized as heterotrophic nitrifying bacteria. Our results suggest that selection of indigenous bacteria that symbiotically interact with algal species is important for better performance of wastewater treatment.

Effects of Microwave Pretreatment on Mesophilic Anaerobic Digestion for Mixture of Primary and Secondary Sludges Compared with Thermal Pretreatment

  • Park, Woon-Ji;Ahn, Johng-Hwa
    • Environmental Engineering Research
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    • v.16 no.2
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    • pp.103-109
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    • 2011
  • This work experimentally determined the effect of thermal and microwave pretreatments on the anaerobic digestion of mixtures of municipal primary and secondary sludges in semi-continuous mesophilic digesters at hydraulic retention times (HRT) of 20, 15, 10, 7, and 5 days. The ratio of soluble chemical oxygen demand (COD) to total COD in thermally pretreated and microwaved sludges at $80^{\circ}C$ was 2.7 and 3.2 times higher than that of raw sludge, respectively. The volatile solids (VS) and COD removal efficiencies in all three digesters fed with raw (control), thermally pretreated (TM), and microwaved (MW) sludges decreased as the HRT was reduced. The highest relative improvement in VS removal compared to the control occurred at the HRT of 5 days in the TM and MW (29 and 41% higher than the control, respectively). At this HRT, improvement in the COD removal efficiencies in the TM and MW compared to the control was 28 and 53%, respectively. Improvements in biogas production compared with the control increased in both the TM and MW as the HRT was reduced to 5 days. The relative improvement in daily biogas production compared to the control from the TM and MW was 33 and 53% higher than the control at the HRT of 5 days, respectively. The results show that microwave pretreatment is more effective than thermal pretreatment in increasing the solubilization degree and mesophilic anaerobic biodegradability of sewage sludge.

Study on the Relationships among Water Quality Parameters in Agricultural Reservoirs (농업용 저수지의 수질항목간의 상관관계 조사)

  • 전지홍;함종화;윤춘경;황순진;김호일
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.44 no.3
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    • pp.136-145
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    • 2002
  • Monitoring data from agricultural reservoirs throughout the country were analyzed to evaluate the limiting factor fur algal growth and relationships between Chl-a, total phosphorus (TP), and total nitrogen (TN). Total 394 reservoirs ranging from below 500 ㎥ to over 50 million ㎥ in storage volume were monitored from 1990 to 2000 with respect to TP, W, Chl-a, and their annual mean values were used fur the analysis. Based on N/P ratio, the dominant limiting factor for algal growth was turned out to be phosphorus in agricultural reservoirs (about 83%). Therefore, the proper managements of phosphorus in the agricultural watershed appear to be crucial to prevent excessive on algal growth. The effects of phosphorus and nitrogen ware most eminent during the summer period. And the effect of nutrients on the algal biomass (Chl-a) development appeared to be greater in smaller the reservoirs than in larger ones. Generally, Chl-a and TP demonstrated a close relationship while that of Chl-a and TN showed less correlationship. Chl-a and chemical oxygen demand (COD) also showed a good relationship. Beth ratios of Chl-a / TP and Chl-a / COD relationships were within the range of literature values. Quantitative analysis of TP and COD is relatively convenient compared to that of Chl-a, and the relationship between TP and COD and Chl-a from this study could be used beneficially for water quality management of agricultural reservoirs and related water quality modeling.

Treatment of Wastewater Containing Ethanolamine in Secondary System of Nuclear Power Plant (Ethanolamine이 포함된 원자력발전소 2차계통 폐수처리)

  • Lee, Han Chul
    • Applied Chemistry for Engineering
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    • v.24 no.1
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    • pp.38-43
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    • 2013
  • ETA (ethanolamine), a pH control agent, has been used as an ammonia substitute in the secondary system of nuclear power plants since 2001. It is impossible to remove ETA from the wastewater treatment system in the nuclear power plant operating currently, because it is the non-biodegradable organics in terms of the environmental. The optimum process and chemicals for the removal of chemical oxygen demand (COD) & N with the field sample were investigated. More than 95% of Ammonium ions, contained much in wastewater, was removed with a diffused aeration system. COD could be removed over 90% through the process that includes the oxidation with mixed peroxidants (sodium persulfate/sodium percarbonate) followed by the physicochemical treatment with coagulants.

The Investigation of COD Treatment and Energy Consumption of Urban Wastewater by a Continuous Electrocoagulation System

  • DEDE SAGSOZ, Yesim;YILMAZ, Alper Erdem;EKMEKYAPAR TORUN, Fatma;KOCADAGISTAN, Beyhan;KUL, Sinan
    • Journal of Electrochemical Science and Technology
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    • v.13 no.2
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    • pp.261-268
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    • 2022
  • In this study, electrochemical treatment of urban wastewater with electrical conductivity of 1000 μS cm-1 and chemical oxygen demand of 250 mg L-1 was investigated using the variables of initial pH value, current density and flow rate. Electrocoagulation was used, in which aluminum and stainless steel were selected, as the electrochemical treatment process. The electrocoagulation process was operated in continuous mode. The data obtained in experimental studies show that the best COD removal efficiency occurred in experiments where the initial pH value was 6. The increase in current density from 5 A to 15 A decreased the removal efficiency from 79 to 67%. The increase in flow rate under constant current density also reduced the efficiency of removal as expected. In experiments in which current density and flow rate were examined together, the increase in flow rate allowed the application of higher current densities. This situation led to considerable reductions in energy consumption values, even if the COD removal efficiency did not significantly increase. The high COD removal obtained with the use of high flow rate and high current density indicates that the electrocoagulation process can be used for high flow rate municipal wastewater treatment.