• Journal of The Korean Society of Agricultural Engineers
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• v.49 no.2
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• pp.75-86
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• 2007

This process which has a connection of biofilter and sulfur-limestone has been developed to treat organic substances including BOD, COD and SS etc. and to treat sulfur-limestone is for denitrification.. The whole process consists of chemical reaction tank, sedimentation tank, trickling filter, denitrification tank The trickling filter is equipped with a reactor filled with absorptive filter, and the sulfur denitrification tank is filled with sulfur-limestone mixed media. After setting up practical facilities whose capacity is 60 tons a day, we have observed the removal efficiencies of pollutants through 60 experiments during Summer and Winter seasons. The average concentration of polluted water was BOD for 3.6 mg/L, $COD_{Mn}$ for 11.3 mg/L, SS for 2.8 mg/L, T-N for 8.6 mg/L, and T-P for 0.8 mg/L, and the rate of treatment efficiencies 96.5%, 84.7%, 96.5%, 79.2%, and 80.8%, respectively was found through the experiments. The average treatment efficiency for BOD and $COD_{Mn}$ was 85.0% and 55.7%, respectively and the average removal efficiency for NH4+-N was 84.9% in the trickling filter. The removal efficiency in the denitrification tank is as follows; The removal rate of $NO_3^--N$ was as high as 93.2% within the compass of pH 6.3 to 7.3 through $16.8{\sim}37.0mg/L$ flown into $NO_3^--N$ and $0.1{\sim}8.3mg/L$ outflown. It had observed that this process has implemented highly efficient and advanced treatment without external carbon sources and internal recycle during its process. In conclusion, this process is suitable for a sewerage in a small village due to the merits of low power consumption and easy maintenance.

• Journal of Applied Biological Chemistry
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• v.51 no.6
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• pp.307-314
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• 2008

To explore the optimal conditions for the removal of $H_{2}S$ gas by biofiltration, various conditions, including inlet $H_{2}S$ concentration, flow rate, moisture, and cell number, were examined. Heterotrophic bacteria were isolated from the compost of the animal excreta. A strain that effectively removed $H_{2}S$ was selected and identified as Rhodococcus rhodochrous B261 by analysis of its 16S rDNA sequence. A cell number of $10^{7}\;cfu/g^{-}compost$ was sufficient to dominate the microbiota, and an effective removal was observed at $H_{2}S$ gas concentrations below 220 mg/L. The moisture content of 33-38% was suitable for activation of the microbial activity and delaying the desiccation. Higher flow rates resulted in lower removal rates of the $H_{2}S$ gas. Under the conditions of $10^7\;cfu/g^{-}compost$, $H_{2}S$ gas concentrations of 220 mg/L, and moisture content of 33-38%, the inlet $H_{2}S$ gas concentrations of 120 and 400 mg/L were completely removed for 34 and 12 days, respectively. The amount of sulfur removed was $2.99{\times}10^{-9}H_{2}S-S/cell$, which was suggested as the amount of sulfur removed by a single cell. The biofilter consisting of the compost and R. rhodochrous B261 could be suitable for a long-term biofilteration for the removal of $H_{2}S$ and other malodorous compounds.

• Journal of the Korean Applied Science and Technology
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• v.22 no.1
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• pp.21-27
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• 2005

This study was conducted to evaluate the biofiltration treatment characteristic for benzene vapor gas. Compost and calcium silicate porous material were used as biofilter fillers. Gas velocity and empty bed retention time were 15 m/hr and 4 min, respectively. Benzene gas removal efficiency of P-Bio (calcium silicate porous material with inoculation) was the highest and maintained in over 98%. After shock input of benzene gas, the removal efficiency of P-Bio biofilter was recovered within 2 days, while 5 days were taken in CP-Bio (compost + calcium silicate porous material mixture with inoculation) and CP (compost + calcium silicate porous material mixture without inoculation) biofilters. The removal efficiency of P-Bio biofilter was near 100% in the loading rate of <$85g/m^3$(filling material)/hr, It was shown that the maximum elimination capacities of P-Bio, CP-Bio, and CP biofilters were 95, 69, and $66\;g/m^3$(filling material)/hr, respectively. Microbial number of P-Bio, which the number was the lowest at start-up, was 3 orders increased on operational day 48. $CO_2$ was generated greatly in order of P-Bio, CP-Bio, and CP biofilters.

• Journal of Korea Soil Environment Society
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• v.4 no.1
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• pp.85-96
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• 1999

Biofiltration is an attractive technique for elimination of VOCs and odorous compounds from low-concentration, high-volume waste gas streams because of its simplicity and cost-effectiveness. The objective of this study was to estimate the removal characteristics of Odorous Compounds including $H_2$S, $NH_3$End BTEX in MSW landfill gases. This Study was conducted at Nanjido landfill site. A compost from the Nanjido composting facility was used as a filling material for biofiltration. Extracted landfill gases were injected into biofilter reactors after mixing with air. Experiments were performed in an incubator being set to $20^{\circ}C$ $H_2$S concentrations were monitored at the depths of 25, 50, 75 and 100cm from the bottom Of the biofilter reactors. 98% of $H_2$S was removed at the filling depth of only 25cm. NH$_3$removal rate was about 85%. Toluene removal rate was the highest among BTEX. Significant pH drop of a filling material was not observed during the biofilter operation of 1 month. Without mixing the landfill gas stream with all, the removal rate of $H_2$S decreased down to 30%.

• Journal of environmental and Sanitary engineering
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• v.21 no.3 s.61
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• pp.15-26
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• 2006

As traffic in city-centre around the world continues to increase, so levels of atmospheric pollutants continue to rise. High concentrations of NOx can have negative effects on human health, and we must find new ways to reduce their levels in the air we breathe. Nitrogen oxide gas (NOx), consisting of nitrogen monoxide (NO) and nitrogen dioxide $(NO_2)$ produced using $O_3$ oxidation, at a low concentration corresponding to that on roads as a result of exhaust from automobiles, was carried out to evaluate the removal characteristics of NOx through a laboratory-scale biofilter packed with soil as a packing material. A mixture media (yellow soil (30%): soil (40%): compost (10%): a used briquet (20%)) was applied. After about 1day of operation, the removal efficiency for $NO_2$ in all experiments with a constant condition ($25^{\circ}C$ and water humidity (60%)) was over 98%. The retention times of the section between phase I and phase II for formation and reduction of $NO_3$ NO and $NO_2$ on the initial $NO_3$ concentration was 50min $(O_3:195\;ppb),\;55min\;(O_3:925\;ppb),\;65min\;(O_3:1743\;ppb),\;70min\;(O_3:2616\;ppb),\;75min\;(O_3:3500\;ppb)$, respectively The soil biofilter system is a unique technology that purifies urban air by utilizing the natural processes that take place in the soil. Although some of the processes are quite complex, they can broadly be summarized as adsorption onto soil particles, dissolution into soil pore water, and biochemical.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.1
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• pp.34-39
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• 2005

Trichloroethylene (TCE) is an environmental contaminant provoking genetic mutation and damages to liver and central nerve system even at low concentrations. A practical scheme is reported using toluene as a primary substrate to revitalize the biofilter column for an extended period of TCE degradation. The rate of trichloroethylene (TCE) degradation by Pseudomonas putida F1 at $25^{\circ}C$ decreased exponentially with time, without toluene feeding to a biofilter column ($11\;cm\;I.D.{\times}95\;cm$ height). The rate of decrease was 2.5 times faster at a TCE concentration of $970\;{\mu}g/L$ compared to a TCE concentration of $110\;{\mu}g/L$. The TCE itself was not toxic to the cells, but the metabolic intermediates of the TCE degradation were apparently responsible for the decrease in the TCE degradation rate. A short-term (2 h) supply of toluene ($2,200\;{\mu}g/L$) at an empty bed residence time (EBRT) of 6.4 min recovered the relative column activity by $43\%$ when the TCE removal efficiency at the time of toluene feeding was $58\%$. The recovery of the TCE removal efficiency increased at higher incoming toluene concentrations and longer toluene supply durations according to the Monod type of kinetic expressions. A longer duration ($1.4{\sim}2.4$ times) of toluene supply increased the recovery of the TCE removal efficiency by $20\%$ for the same toluene load.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.2
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• pp.125-131
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• 2003

This study was carried out to develop INSUB(Indirected Aerated Submerged Biofilter) which can remove organics, nitrogen and phosphorus with an advanced treatment system. The results were as followed in laboratory model experiment. As for treatment of sewage, when economical efficiency was considered in practice, the highest removal efficiency was at 18hr of HRT, 1.017m/hr of superficial velocity and 40% of media packing ratio. Each removal efficiency for $COD_{cr}$, $COD_{Mn}$, $BOD_5$, T-N, and T-P was 90.6, 85.3, 95.0, 52.3 and 56.8%. To remove the nitrogen and phosphorus With high efficiency, first of all, denitrification have to be completed, then uptake of phosphorus have to completed. Therefor, mixture of anoxic and aerobic reactor was necessary for the high removal efficiency of nitrogen and phosphorus in INSUB.

• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.3
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• pp.136-144
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• 2001

Two organic materials, peat and rock wool were used for removal of $H_2S$ by a biofilter inoculated with night soil sludge. By gradually increasing the inlet load of $H_2S$, the complete removal capacity, which was defined as the inlet load of $H_2S$ that was complete removed, and the maximum removal capacity of $H_2S$, which was the value when the removal capacity leveled off for organic materials, were estimated. Both values for Rock wool are larger than peat, based on a unit dry weight of material. By using kinetic analysis, the maximum removal rate of $H_2S$, $V_m$, and the saturation constant, $K_s$, were determined for all packing materials and the values of $V_m$ for rock wool was found to be larger. By using the kinetic parameters, the removal rates for $H_2S$ were compared both packing materials, and rock wool showed better performance for the removal of $H_2S$ in the inlet concentration range of 0~200ppm.

• Journal of Korean Society of Water and Wastewater
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• v.13 no.1
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• pp.81-94
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• 1999

This study aims at a proposal of the plan that can improve raw water quality by an experimental study using influent water of Nak-dong river, which has been used as raw water for drinking in U-city, through the establishment of the submerged biofilter process PILOT PLANT of media packing channel method. From the analysis of removal efficiency for each water quality item of the collected sample, following results are obtained. First of all, the removal rate of suspended material, BOD, COD, T-N, TOC, turbidity, and $NH_3$ -N appear 82%, 78%, 42%, 15%, 57%, 43%, 54%, and 55% respectively and it is known that the submerged biofilter process of media packing channel method takes effects on water quality improvement from the above analysis results of water treatment efficiency. And the analyzed results for water temperature, residence time, and activities of microorganism, which can be the factors affect on water quality improvement, are as follows. 1) The removal rate variation of SS, BOD, and COD attendant on water temperature change is examined and it is known that the removal rate increases at $13^{\circ}C$ or above. 2) The removal rate of SS, BOD, and COD attendant on residence time is most active in the range of 0~18hr, 0~1.8hr, 0~2.7hr respectively, so it is found that the removal rate becomes smaller after 2.7hr. 3) From the examination of microorganism activity with the abundance of normal bacteria, it is found that the floating bacteria decrease as the flow distance from raw water inflow point of PILOT PLANT increases, and the adhesive bacteria have no concern with the flow distance. And it its known that the biomass of fine algae decreases as the flow distance from the raw water inflow point of PILOT PLANT increases from the examination with Chl-a.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.465-469
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• 2006

Two mesophilic trickling bed bioreactors filled with two different types of media, hydrophilic- and hydrophobic-cubes, were designed and tested for hydrogen production via anaerobic fermentation of sucrose. Each reactor consisted of a column packed with polymeric cubes and inoculated with heat-treated sludge obtained from anaerobic digestion tank. A defined medium containing sucrose was fed with changing flow rate into the capped reactor, hydraulic retention time and recycle rate. Hydrogen concentrations in gas-phase were constant, averaging 40% for all conditions tested. Hydrogen production rates increased up to $10.5 L{\cdot};h^{-1}{\cdot}L^{-1}$ of reactor when influent sucrose concentrations and recycle rates were varied. Hydrophobic media provided higher value of hydrogen production rate than hydrophilic media at the same operation conditions. No methane was detected when the reactor was under a normal operation. The major fermentation by-products in the liquid effluent of the both trickling biofilters were acetate and butyrate. The reactor filled with hydrophilic media became clogged with biomass and bio gas, requiring manual cleaning of the system, while no clogging occurred in the reactor with hydrophobic media. In order to make long-term operation of the reactor filled with hydrophilic media feasible, biofilm accumulation inside the media in the reactor with hydrophilic media and biogas produced from the reactor will need to be controlled through some process such as periodical backwashing or gas-purging. These tests using trickling bed biofilter with hydrophobic media demonstrate the feasibility of the process to produce hydrogen gas in a trickle-bed type of reactor. A likely application of this reactor technology could be hydrogen gas recovery from pre-treatment of high carbohydrate-containing wastewaters.