• Journal of Korea Soil Environment Society
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• v.4 no.2
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• pp.193-201
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• 1999

This study was conducted to check the applicability of pilot-scale co-composting for the remediation of diesel contaminated soil during the winter. Nutrients and microbes were added to enhance the efficiency of bioremediation and fermenting composts were also added to stimulate the microbial activities. As a result. the soil pile was kept at adequate temperature for the bioremediation during the test period of 30∼40 days and initial concentration(2,340mg TPH/kg dry soil) was reduced to 216mg TPH/kg dry soil (approximately 91% removal). During the initial 10∼30 days, it was found that the TPH concentration and the microbial population were rapidly reduced and increased. respectively. The co-composting technology studied can be effectively applied to remediate the diesel contaminated soil during the winter.

• Journal of Korean Society of Water and Wastewater
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• v.10 no.2
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• pp.104-116
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• 1996

Anaerobic digestion is generally used for the treatment of volatile organic solids such as manure and sludge from waste water treatment plants. However, the reaction rate of anaerobic process is slow, and thus it requires a large reactor volume. To minimize such a disadvantage, physical and chemical pre-treatment is generally considered. Another method to reduce the reactor size is to adopt different reactor system other than CSTR. In this paper, the effects of heat pre-treatment and reactor configurations on the anaerobic treatability of volatile solids was studied. Carrot, kale, primary sludge, and waste activated sludge was chosen as the test materials, and the BMP method was used to evaluate the maximum methane production and first order rate constants from each sample. After the heat treatment at $130^{\circ}C$ for 30min., the measured increase in SCOD per gram VS was up to 394 mg/L for the waste activated sludge. However, the methane production potential per gram VS was increased for only primary and waste activated sludge by 17-23%, remaining the same for carrot and kale. The overall methane production process for the tested solids can be described by first order reactions. The increased in reaction constant after heat pre-treatment was also more significant for the primary and waste activated sludge than that for carrot and kale. therefore, the heat pre-treatment appeared to be effective for the solids with high protein contents rather than for the solids with high carbohydrate contents. Among the four reactor systems studied, CSTR, PFR, CSTR followed by PFR, and PFR with recycle, CSTR followed by PFR appeared to be the best choice considering methane conversion rate and the operational stability.

• Journal of Digital Convergence
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• v.11 no.5
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• pp.237-243
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• 2013

This study aims to examine the modified $A^2/O$ process is useful to reduce the environmental pollution caused by nutrient in wastewater. Specific results are as follows: The removal rate was evaluated at each time period, ie., 18h, 8h, 6h, and 3h after the reaction started. The anoxic rate was more than 94-97% from 18h to 6h but was less than 50% before 6h. Thus, the test of nitrification was done using 6h as the optimal anoxic retention time and the aerobic retention time set at 24h. When the flow change was 1:1, the average ammonia concentration inputted was $30mg/{\ell}$. Returned top nitric acid solution and the concentration of ammonia solution falling into the anoxic reactor was about 50％ of the initial concentration, and the flow change was 1:2, the concentration of ammonia falling into the anoxic reactor was about 62% of that of influxed ammonia. And the results of this study showed that the nitrogen removal rate can be improved by inputting untreated nitric acid and changing the flow of top nitrate solution using the modified $A^2/O$ method.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.2
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• pp.193-200
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• 2010

This study evaluated treatability of soluble Mn(II) using multifunctional sand media simultaneously coated with iron and manganese. In the preparation of IMCS(Iron and Manganese Coated Sand), 0.05 M Mn(II) solution and Fe(III) solution was mixed with sand at pH 7. The mineral type of IMCS was identified as the mixture of ${\gamma}-MnO_2$, goethite and magnetite($F_{e3}O_4$). The contents of Mn and Fe coated onto sand were 826 and 1676 mg/kg, respectively. The $pH_{pzc}$ of IMCS was measured as 6.40. The removal of soluble Mn(II) using IMCS and oxidants such as NaOCl and $KMnO_4$ was investigated with variation of the solution pH, reaction time and Mn(II) concentration in a batch test. The removal of Mn(II) on IMCS was 34% at pH 7.4 and the removals of Mn(II) on IMCS in the presence of NaOCl(13.6 mg/L) at pH 7 and $KMnO_4$(4.8 mg/L) at pH 7.6 were 96% and 89%, respectively. The removal of Mn(II) using IMCS and oxidants followed a typical cationic type, showing a gradual increase of removal as the solution pH increased. The removal of Mn(II) was rapid in the first 6 hrs and then a constant removal was observed. The maximum removed amount of Mn(II) on IMCS-alone and IMCS in the presence of oxidants such as NaOCl(13.6 mg/L) and $KMnO_4$(4.8mg/L) were 833.3, 1428.6 and 1666.7 mg/kg, respectively. Mn(II) removal onto the IMCS in the presence of oxidants was well described by second-order reaction and Langmuir isotherm expression.