• Journal of Environmental Science International
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• v.11 no.8
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• pp.819-827
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• 2002

Laboratory scale experiments were conducted to evaluate the performance of a biofilter for eliminating dimethyl sulfide(DMS). A commercial compost/pine bark nugget mixture served as the biofilter material for the experiments. The gas flow rate and DMS concentration entering the filter were varied to study their effect on the biofilter efficiency. The operating parameters, such as the residence time, inlet concentration, pH, water content, and temperature, were all monitored throughout the filter operation. The kinetic dependence of the DMS removal along the column length was also studied to obtain a quantitative description of the DMS elimination. High DMS removal efficiencies(>95％) were obtained using the compost filter material seeded with activated sludge. DMS pollutant loading rates of up to 5.2 and 5.5 g-DMS/m$^3$/hr were effectively handled by the upflow and downflow biofilter columns, respectively. The macrokinetics of the DMS removal were found to be fractional-order diffusion-limited over the 9 to 25 ppm range of inlet concentrations tested. The upflow column had an average macrokinetic coefficient(K$\_$f/) of 0.0789 $\pm$ 0.0178 ppm$\^$$\sfrac{1}{2}$//sec, while the downflow column had an average coefficient of 0.0935 $\pm$ 0.0200 ppm$\^$$\sfrac{1}{2}$//sec. Shorter residence times resulted in a lower mass transfer of the pollutant from the gas phase to the aqueous liquid phase, thereby decreasing the efficiency.

• Korean Journal of Environmental Agriculture
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• v.29 no.3
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• pp.232-238
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• 2010

The objective of this study was to investigate a small sewage treatment system. This system was developed to improve a nitrogen and phosphorus removal efficiency and generate less solid using upflow septic tank(UST) - aerobic filter(AF) system. The UST equipped with an aerobic filter, the filter was fed with both raw sewage and recycled effluent from the UST to induce the denitrification and solid reduction simultaneously. Overall removal efficiencies of COD and total nitrogen(TN) were above 96% and 73% at recycle ratio of 200%, respectively. Critical coagulant dose without the biochemical activity was found to be 40 mg/L. Removal efficiency of total phosphorus(TP) in influent was above 90% by chemical and biological reactions. Although the phosphorus concentration was low under the high alkalinity in raw sewage, the pH value was unchanged by the coagulant dose.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.3
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• pp.383-390
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• 2011

In this study, a process combined biofiltration with sulfur-utilizing autotrophic denitrification and membrane separation was proposed to examine the efficiency of nitrogen removal. As an experimental device, hollow-fiber module was installed in the center of reactor to generate the flux forward sulfur layer in the cylinder packed with granular sulfur. In addition, a simple module was installed in activated sludge aeration tank which inside and outside of sulfur-using denitrification module was covered with microfilter and the module was considered as an alternative of clarifier. The experiment for developing new MBR process was carried out for three years totally. As the results of first two-year experiment, successful nitrogen removal performance was revealed with lab-scale test and pliot scale plant using artificial wastewater and actual plating wastewater. In this year, pilot scale test using actual domestic wastewater was performed to prove field applicability. As the results, high-rate nitrogen removal performance was confirmed with about 0.19 kg ${NO_3}^--N/m^3$ day of rate. Also significant fouling and pressure increase were not found during the experiment. And, the production ratio of sulfate and the consumption ratio of alkalinity showed a slightly higher value about 311 mg ${SO_4}^{2-}/L$ and 369 mg $CaCO_3$/L, respectively. In conclusion, the developed MBR process can be utilized as an alternative for retrofiting existing wastewater plants as well as new construction of advanced sewage wastewater treatment plants, with cost-effective merit.

• Journal of Korean Society on Water Environment
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• v.20 no.4
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• pp.357-364
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• 2004

In this study, biodegradable organic matter was divided into a rapidly biodegradable fraction($BDOC_{rapid}$) and a slowly biodegradable fraction($BDOC_{slow}$) for various waters with different types of DOC. These fractions($BDOC_{rapid}$ and $BDOC_{slow}$) were defined by using a shaking incubation method modified from Carlson's method. Also, in this study, optimum incubation time and accuracy were investigated to determine $BDOC_{rapid}$ and $BDOC_{slow}$. When suspended bacteria obtained from raw water and BAC effluent, or attached bacteria from BAC was respectively used as an inoculum, the difference in total BDOC($BDOC_{total}$) was minimal. Therefore, total BDOC was determined in 7~8 days by the shaking method, which is comparable with Servais's method by which BDOC was determined in 28 days. In addition, the difference of BDOC between these two methods was within 7%. Although $BDOC_{rapid}$ and $BDOC_{slow}$ were effectively determined by a method defined by Klevens, the difference in optimal incubation time was significant for different water samples. However, when using the shaking method, optimal incubation time for $BDOC_{rapid}$ was found to be 3 days, therefore, the $BDOC_{rapid}$ was defined as the difference between $DOC_0$ and $DOC_{3days}$, and $BDOC_{slow}$ was defined as the difference between $BDOC_{total}$ and $BDOC_{rapid}$. As a conclusion, for determining the fraction of BDOC using the shaking method, the concentrations of an inoculurns and optimal incubation times used in this study were very effective.

• Korean Chemical Engineering Research
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• v.53 no.4
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• pp.482-488
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• 2015

Biological treatment is promising alternative to conventional air pollution control method. Bioreactors for air pollution control have found most of their success in the treatment of dilute and high flow waste air streams containing volatile organic compounds and odor. The studies of mass transfer in biotrickling filters for air pollution control were of importance in order to control and optimize the purification process. The objectives of this study were to develop the experimental methodologies to evaluate the mass transfer coefficients of gas/liquid(trickling liquid), gas/solid(biomass) and liquid/solid in three phase biotrickling filtration. Also, this study characterized the influence factors on mass transfer such as dynamic holdup volume, gas/liquid flow rate ratio, biomass weight in reactor and recirculation rate of trickling medium for each phase of biotrickling filter.

• Korean Chemical Engineering Research
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• v.53 no.4
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• pp.489-495
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• 2015

A fundamental mathematical model for mass transfer processes has been used to understand the air pollution control process in biotrickling filtration and to evaluate the mass transfer coefficients of gas/liquid (trickling liquid), gas/solid (biomass) and liquid/solid based upon experimental results and mathematical model calculations for selected operating conditions. The mass transfer models for the utilization of the steady-state mass balance for gas/liquid, and dynamic mass balance model for gas/solid & liquid/solid in biotrickling filters were established and discussed. The mass transfer model considered the reactor to comprise finite sections, for each of which dynamic mass balances for gas/solid and liquid/solid system were solved by numerical analysis code (numerical iteration). To determine the mass transfer coefficients ($K_La$) of gas/liquid, gas/solid & liquid/solid in a biotrickling filter, the calculation results based upon mass balance equation was optimized to coincide with the experimental results for the selected operating conditions. Finally, this study contributed the development of experimental methods and discussed the mathematical model to determine the mass transfer coefficients in a biotrickling filtration for air pollution control.

• Journal of Life Science
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• v.22 no.9
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• pp.1237-1242
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• 2012

The use of biological-activated carbon (BAC) processes in water treatment involves biofiltration, which maximizes the bacteria's capabilities to remove organic matter. In this study, the distribution of the bacterial community was assessed in response to different types of BAC processes applied downstream in the Nakdong River. The bacterial biomass and activity were $1.20{\sim}34.0{\times}10^7$ CFU/g and 0.61~1.10 mg-C/$m^3{\cdot}hr$ in coal-based BAC, respectively. The attachment of the bacterial biomass and the removal efficiency of the organic carbon were greatest with the coal-based activated carbon. The bacteria attached to each activated carbon material were detected in the order of Pseudomonas genus, Chryseomonas genus, Flavobacterium genus, Alcaligenes genus, Acinetobacter genus, and Spingomona genus. Pseudomonas cepacia was the dominant species in the coal-based materials, and Chryseomonas luteola was the dominant species in the wood-based material.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.773-778
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• 2011

Long-term continuous application of livestock by-products to agricultural land may adversely affect the soil characteristics and the crop yield. Five year term study from 2007 was carried out to assess the effects of repeated application of low-concentration swine slurry on soil chemical properties including phosphate and heavy metal contents and yield of tomato (Lycopersicon esculentum) and cucumber (Cucumis sativus L.) in a greenhouse. Treatments were conventional chemical fertilizers and three application rates of low-concentration swine slurry (Slurry composting and biofiltration, SCB): 50%, 100%, and 200% of recommended nitrogen fertilization. For swine slurry treatment of 50% nitrogen, deficient nitrogen was supplemented with urea fertilizer. The soil phosphorus and heavy metal contents after five year continuous application of swine slurry were not significantly higher than those of chemical fertilizer use. Repeated application of the swine slurry alone for five years resulted in relatively high soil exchangeable potassium and sodium compared with chemical fertilizer treatment. Contents of heavy metals in leaves of tomato and cucumber did not show significant difference among treatments. Yields of the crops for the swine slurry were not significantly different from that of chemical fertilizer. The results imply that continuous application of the swine slurry may not influence levels of soil phosphate and trace elements in greenhouse soils but could accumulate potassium and sodium in the soil.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.2
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• pp.184-191
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• 2007

Coal-, coconut- and wood-based activated carbons and anthracite were tested for an adsorption and biodegradation performances of nitrogenous chlorinated by-products such as chloropicrin, DCAN, DBAN and TCAN. In early stage of operations, an adsorption performance was a main mechanism for removal of nitrogenous chlorinated by-products, however as increasing populations of attached bacteria, the bacteria played a major role in removing nitrogenous chlorinated by-products in the activated carbon and anthracite biofilter. It was also investigated that the compounds were readily subjected to biodegrade. Whilst the coal- and coconut-based activated carbons were found most effective in adsorption of the compounds, the anthracite was worst in adsorption of the compounds. Highest populations and activity of attached bacteria were shown in the coal-based activated carbon. The populations and activity of attached bacteria decreased in the order: coconut-based activated carbon > wood-based activated carbon > anthracite. The attached bacteria were inhibited for removal of the compounds at temperatures below $10^{\circ}C$. The attached bacteria were more active at higher water temperatures$(20^{\circ}C\;<)$ but less active at love. water temperature$(10^{\circ}C\;>)$. The removal efficiencies of the compounds obtained using coal-, coconut- and wood-based activated carbons and anthracite were directly related to the water temperatures. In particular, water temperature was the most important factor for removal of the compounds in the anthracite biofilter because the removal of the compounds depended mainly on biodegradation. Therefore, the main removal mechanism of the compounds the main mechanism on the removal of the compounds using activated carbon was both adsorption and biodegradation by the attached bacteria. The observation suggests that using coal-based activated carbon is the best for removal of nitrogenous chlorinated by-products in the water treatment.

• Horticultural Science & Technology
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• v.33 no.4
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• pp.605-617
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• 2015

The ultimate goal of this research is to develop a botanical biofiltration system that combines a green interior, biofiltering, and automatic irrigation to purify indoor air pollutants according to indoor space and the size of biofilter. This study was performed to compare the stability of air flow characteristics and removal efficiency (RE) of fine dust within a wall-typed (vertical) botanical biofilter depending on humidifying cycle and to investigate RE of volatile organic compounds (VOCs) by the biofilter. The biofilter used in this experiment was designed as an integral form of water metering pump, water tank, blower, humidifier, and multi-level planting space in order to be suitable for indoor space utilization. As a result, relative humidity, air temperature, and soil moisture content (SMC) within the biofilter showed stable values regardless of three different humidifying cycles operated by the metering pump. In particular, SMCs were consistently maintained in the range of 27.1-29.7% during all humidifying cycles; moreover, a humidifying cycle of operating for 15 min and pausing for 45 min showed the best horizontal linear regression (y = 0.0008x + 29.09) on SMC ($29.0{\pm}0.2%$) during 120 hour. REs for number of fine dust (PM10) and ultra-fine dust (PM2.5) particles passed through the biofilter were in the range of 82.7-89.7% and 65.4-73.0%, respectively. RE for weight of PM10 passed through the biofilter was in the range of 58.1-78.9%, depending on humidifying cycle. REs of xylene, ethyl benzene, total VOCs (TVOCs), and toluene passed through the biofilter were in the range of 71.3-75.5%, while REs of benzene and formaldehyde (HCHO) passed through the biofilter were 39.7% and 44.9%, respectively. Hence, it was confirmed that the wall-typed botanical biofilter suitable for indoor plants was very effective for indoor air purification.