Complaints about foul odors are emerging as an issue, and the number of complaints is steadily increasing every year. Biofiltration is known to remove harmful or odorous substances from the atmosphere by using microorganisms, and full-scale biofilters are being installed and operated in various environmental and industrial facilities. In this study, the current status and actual odor removal efficiency of full-scale biofilters installed in publicly owned treatment facilities such as sewage, manure, and livestock manure treatment plants were investigated. In addition, the effects of design and operating factors on their efficiency were also examined. As a result, it was found that odor prevention facilities with less than 30% odor removal efficiency based on complex odors accounted for 40%-50% of the biofilters investigated. In investigating the appropriate level of operating factors on odor removal efficiency, it was found that compliance with the recommended values p lays a significant role in improving odor removal efficiency. In the canonical correlation analysis for the on-site biofilter operation and design data, residence time and humidity were found to be the most critical factors. The on-site biofilter operation and design data were analyzed through canonical correlation analysis, and the residence time and humidity maintenance were found to be the most important factors in the design and operations of the biofilter. Based on these results, it is necessary to improve the odor removal efficiency of on-site biofilters by reviewing the effectiveness of the operation factors, improving devices, and adjusting operating methods.

In this study, the removal performance of high-concentration H2S and complex odors was evaluated for bio-filters installed in sewage treatment plants and manure treatment plants. The amount of odor generation according to temperature was found to be higher in summer than in spring. It was found that the longer the empty bed retention time of the bio-filter, the higher the odor removal efficiency. Therefore, in order to effectively remove odors, it is necessary to maintain a sufficiently long residence time when designing a bio-filter. In addition, a case in which a bio-filter and a wet pre-treatment system were combined to remove high-concentration odors was studied. The result showed that the wet pre-treatment was effective in removing high-concentration odors. In particular, most of the hydrogen sulfide could be adequately removed by wet pre-treatment.

Two lab-scale trickle-bed type biofilters with a single fungal species (Aspergillus fumigatus, Acidomyces acidophilus, respectively) have been studied to investigate the simultaneous removal of inorganic (hydrogen sulfide) and organic (butyl acetate) compounds. The biofilter with Aspergillus fumigatus treated simultaneously two different compounds with removal capacity of 1,511 mgS/m3/hr and 6,324 mgC/m3/hr; and the biofilter inoculated with Acidomyces acidophilus had the removal capacity of 1,254 mgS/m3/hr and 6,045 mgC/m3/hr. Stable operational performance was observed in both biofilters under an acidic condition of pH 2 to 4. Based on pseudo-first-order removal rates as a function of depth in the biofilter, Aspergillus fumigatus showed a twice faster rate of hydrogen sulfide removal than Acidomyces acidophilus, 15.9% (Aspergillus fumigatus) and 17.9% (Acidomyces acidophilus) of total sulfur removed were oxidized to produce sulfates, and 77.8% (Aspergillus fumigatus) and 79.4% (Acidomyces acidophilus) were accumulated in the form of S0 through the bed in both biofilters, respectively.

바이오 의약품 생산과정의 대부분 공정에서 분리막이 사용되고 있다. 분리막 공정은 다른 공정의 전처리, 공정 자 체의 불순물 분리, 바이러스 제거, 목표 생성물 농도 조절 및 완충 용액 교환 등에 사용된다. 인체에 사용하는 바이오 의약품 의 바이러스 오염은 심각한 임상 결과와 직결되는 민감한 문제이기 때문에 바이러스 필터는 제품의 효능과 안정성을 보장하 기 위해 중요한 역할을 한다. 바이러스 필터는 일반적으로 표면 개질된 PVDF, PES, CRC 등 다양한 고분자로 만들어진 복합 다층 구조를 가지고 있다. 제조업체에 따라 대칭(symmetric) 또는 비대칭(asymmetric) 등 다른 기공 구조와 형태를 가지고 있 으며, 주름막, 평판 시트 또는 중공사 형태로 사용된다. 바이러스 필터는 Asahi Kasei 를 비롯해 Millipore, Pall, Sartorius 등 몇몇 해외 업체들이 독점적으로 국내에 공급하고 있다. 바이러스 필터를 대체하려면 검증작업을 통해 규제기관의 승인을 받 는 등 상당한 시간과 비용이 소요된다. 최근 일본의 수출규제로 국산화가 중요해진 만큼 제거 성능 고도화 등 선제적으로 기 술자립도를 높여가야 한다.

A lab-scale biofilter with fungal growth has been studied to investigate the removal of gas-phase hydrogen sulfide. The biofilter inoculated initially with the aerobic activated sludge was operated for 100 days under acidic condition, and 0.36 L/d of the buffered nutrient with 0.05 g/L Chloramphenicol and Gentamicin was injected into the biofilter. The critical removal capacity of hydrogen sulfide was up to 22 g/m³/h. The pH of the effluent liquid was stable at pH 1.5-2, corresponding to the volatile suspended solids of 20-50 mg/L. In microbial analysis through the plate count method, it was found that fungi were dominant over bacteria. The fungi isolated from biomass in the bilfilter were identified as Acidomyces acidophilus and Aspergillus fumigatus. Sulfate and thiosulfate were also detected in liquid samples, as a result of the biological sulfur oxidation in the biofilter bed. For the analysis of sulfur mass balance, the accumulated mass of sulfate and thiosulfate reached up to 67.5% of inlet sulfur. Sulfur was also detected on the biomass collected from the biofilter through Scanning electron microscopy/Energy dispersive X-ray spectroscopy.

In order to reduce odor and methane emission from the landfill, open biocovers and a closed biofilter were applied to the landfill site. Three biocovers and the biofilter are suitable for relatively small-sized landfills with facilities that cannot resource methane into recovery due to small volumes of methane emission. Biocover-1 consists only of the soil of the landfill site while biocover-2 is mixed with the earthworm casts and artificial soil (perlite). The biofilter formed a bio-layer by adding mixed food waste compost as packing material of biocover-2. The removal efficiency decreased over time on biocover-1. However, biocover-2 and the biofilter showed stable odor removal efficiency. The rates of methane removal efficiency were in order of biofilter (94.9%)>, biocover-1(42.3%)>, and biocover-2 (37.0%). The methane removal efficiency over time in biocover-1 was gradually decreased. However, drastic efficiency decline was observed in biocover-2 due to the hardening process. As a result of overturning the surface soil where the hardening process was observed, methane removal efficiency increased again. The biofilter showed stable methane removal efficiency without degradation. The estimate methane oxidation rate in biocover- 1 was an average of 10.4%. Biocover-2 showed an efficiency of 46.3% after 25 days of forming biocover. However, due to hardening process efficiency dropped to 4.6%. After overturn of the surface soil, the rate subsequently increased to 17.9%, with an evaluated average of 12.5%.

A biofilter filled with sintered glass media and wood bark media were developed and tested. Acetic acid and ammonia added in brewery wastewater were used as an artificial odor source. The Reynolds’ number (NRe) was below 130 in the loading range of 3~5 m3/m2-min, while the pressure drop was less than 6 mmH2O. The average removal efficiency of acetic acid was 87.6% and 71.5% at surface loading rate of 3.1 m3/m2-min and 4.4 m3/m2- min, respectively. The acetic removal capacities were 8.1~14.3 g/m3-min with the mass loading rates of 11.7~22.4 g/m3-min, indicating very high performance. However, the acetic removal capacity was sharply decreased at the mass loading rate of 20 g/m3-min. The average removal rate of ammonia was 38% and 25% at the surface loading rates of 3.1 m3/m2-min and 4.4 m3/m2-min, respectively. The ammonia removal capacity was 0.47~0.88 g/m3-min in the range of 11.7~22.4 g/m3-min mass loading rates. The intensity of complex odor was also decreased based on the findings in the measurement using the direct olfactory method and the GC analysis.

Characteristics of commercial antimicrobial filter media for bioaerosol removal were estimated. A chitoasn/ medium filter, a catechin/HEPA filter, a silver/HEPA filter, a copper/pre filter, a electret cabin filter and a non-electret cabin filter were used for estimation. Filtration efficiency and antimicrobial efficiency was tested using Escherichia coli and Staphylococcus epidermidis. The electret cabin filter and the chitosan/medium filter showed the highest filtration and antimicrobial efficiency, respectively.

In this study, we attempt to analyze biofilter"s removal efficiency for volatile organic compounds from paint factory. this experiment conducted in a pilot plant with microorganisms immobilized polyurethane foam. 7 main components (Toulene, MEK, MIBK, o-Xylene, m-Xylene, Butyl acetate, Ethyl benzene) emitted from factory ventilation opening were analyzed. During the test period, the biofilter treated VOCs in 5 seconds (EBCT) and pressure drop was less than 30 ㎜H₂O/m in media. Removal efficiencies of all components were between 80~90% in 10 days of operation and higher than 94% after 40 days. The result of this experiment shows that biofilter can be useful technology for VOCs removal in the paint industry.

Pyridine could be successfully removed in the polyurethane(PU) biofilter inoculated with activated sludge treating industrial wastewater. The elimination capacity for pyridine in the PU biofilter was approximately 27 g m⁻³ h⁻¹ at the tested loading range, The pH value of drainage was increased due to the accumulation of ammonia which was one of the metabolites of pyridine, Four pyridine-degrading bacteria were isolated from the PU biofilter, and they were closely related with Rhodococcus pyridinivorans(98~99% similarity). The specific growth rate of the isolate in the medium supplemented with pyridine as a sole carbon and energy source were ranged from 0.038 h⁻¹ to 0.051 h⁻¹.

In this study, we attempted to analyze removal efficiency of odorous compounds emitted from Grit chamber and night soil treatment facility using biofilter with microbial catalyst. Air dilution method was used for mixed odor gases analysis. UV-vis spectrophotometer for ammonia and Hydrogen sulfide, Methyl mercaptan, Dimethyl sulfide, Dimethyl disulfide were measured using GC/PFPD. Sample gases were collected at the inlet and outlet of biofilter. The analysis result showed that average concentration of major odorous compounds were ammonia with 5,100 ppb and hydrogen sulfide with 797 ppb from grit chamber and ammonia with 1,407 ppb and hydrogen sulfide with 2,475 ppb from night soil treatment facility. Hydrogen sulfide was the most influential compound of malodor based on odor quotient index. The average dilution threshold of odor was 923 at grit-chamber and 1,267 at night soil treatment facility. The removal efficiency of odorous compounds from sewage treatment facility were more than 94% using polyurethane foam biofilter within empty bed contact time 3sec. The emitted concentration to the atmosphere was satisfied with the criterion of the offensive odor control law.

Biofilters are a wide-spread technology over physical and chemical methods for the treatment of odor compounds because many lab and field-scale operations have demonstrated effective treatments for gas streams contaminated with a low concentration of various odor compounds. Therefore, biofilter processes are classified as one of the best available control technologies in Europe. However, biofilter performance can not be reliable when they are operated at dynamic loading conditions over an extended period. Several methods have been proposed and implemented to overcome some operational problems such as nutrient depletion and clogging. In spite of these efforts, conventional biofilters require improvement to effectively control high concentrations of odor compounds. As a results, additional attempts to resolve the problems and expand biofilter application range are being studied.

The purpose of this study is to estimate the performance of various biofilter media using ammonia. The results can be summarized as follows: 1) The removal of ammonia using various biofilter media was performed, and inorganic media was proved to be better than the organic media. 2) From the inorganic media, fibril form was most superior. 3) Because fibril form is expensive, PU was determined to be the optimum biofiler media for ammonia removal.

Bioaerosols are airborne particles of biological origins including viruses, bacteria, fungi, and all varieties of living materials. In suitable hosts, bioaerosols are capable of causing acute or chornic diseases that may be infectious, allergenic, or toxigenic. Bioaerosols from outdoor air accumulate on filters of heating, ventilating and air conditioning (HVAC) system in large quantities and are able to multiply there under certain conditions. In this study, silver was coated on activated carbon fiber (ACF) filters by an electroless plating method, and their efficacy for bioaerosols removal was tested. Physical filtration and biological antimicrobial test were performed. SEM and XRD analyses were used to characterize the morphology and components of ACF filters. Electroless silver-plated ACF filters showed antimicrobial efficiency, whereas pure ACF filters did not. It was found that electroless silver plating did not influence the physical filtration efficiency of ACF filters.