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.

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.

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.

The objective of this study was to investigate the response characteristics and performance of a biofilter in the removal of ammonia, as a malodor compound. A trickle-bed type biofilter was applied for this study, and operated at the ammonia loading rate of 0.97-15.52 g/m3·h. The results of the experiment indicate that the critical loading rate of ammonia to the biofilter was 10.7 g/m3·h and the elimination capacity was 11.6 g/m3·h. The analysis of nitrogen mass balance in the reactor indicates that inlet nitrogen as gas phase was converted through the biofilter into NH4 + (41.5% by mass), NO2 - (43%), and NO3 - (15%) as the available form of nitrogen in the effluent liquid. Free ammonia concentration in the effluent liquid was estimated as being in the range from 0.14 to 2.93 mg/L (average 1.7 mg/L) during the experimental period.

본 논문은 음식물쓰레기의 퇴비화에 타당성을 위한 총론적인 논문이다, 또한 다양한 연구논문들을 조사함으로써 음식물 쓰레기의 퇴비화를 통해 얻어진 최종산물이 휘발성 유기화합물 및 냄새제거를 위한 바이오필터로서 적합성을 제고해 보고자 하였다. 우선 음식물쓰레기는 높은 유기물 함유량을 가지고 있어 퇴비화에 적합하지만 반면 높은 수분함량과 물리적으로 낮은 강도로 인해 퇴비화 과정을 어렵게 할 수 있다. 많은 연구자들에 의해 퇴비를 이용한 바이오필터링에 대한 연구가 진행중임에도 불구하고, 명확한 메커니즘의 규명이 되어 있지 않고 있으며 특히 음식물쓰레기에 대한 연구는 미비한 실정이다. 따라서 본 논문에서는 특히 음식물쓰레기 퇴비의 바이오필터로서의 사용가능성에 대한 기본적이고 중요한 자료를 제공하고자 한다.

The purpose of this experimental research was focused to improve the quality of the effluent and the yielded sludge when the papermill wastewater was treated by the indirect aerated submerged biofilter as a second treatment method of papermill wastewater. Changing the various experimental factors(Nutrient additions or not, HRT, F/M ratio, recirculation ratio, etc) with indirect aerated biofilter, the results obtained are as follows. 1. Because of the microbes concentration could be sustained to $9,000mg/l$ in submerged biofilter and then the volumetric organic loads could be increased to $2.7kg-BOD/m^3/day$(that of activated sludge is $0.8kg-BOD/m^3/day$), the reactor volume can be reduced to one third of the activated sludge treatment. 2. Because of the yield coefficient(Y) and the endogenous decay coefficient(kd) were revealed 0.4 and 0.07/d, the yielded sludge volume was reduced by for compared with that of the activated sludgg process. 3. The concentration of the sloughed sludge in the reactor was 2.62~4.01%, so the thickener could be omitted in the papermill wastewater sludge treatment process. 4. When the operating was conducted at HRT of 4hrs, the treatment efficiencies of BOD and COD were obtained 80% and 70%, Therefore operating time can be reduced to one half of the activated sludge treatment.

The final goal of this research is to develop a miniaturized botanical biofilter using a wick-typed automatic humidifier for stabilizing soil moisture content (SMC) and purifying indoor air pollutants by the biofilter. This new biofilter equipped with wick-typed automatic humidifier was manufactured as more compacted design removing an absorption tower-typed humidifier compared with the previous big-sized biofilter made in 2015. This study was performed to compare changes of SMCs among floors depending on the number of wicks installed on the humidifier within the novel biofilter, and to compare changes of SMCs and plant growth parameters before and after planting Spathiphyllum wallisii ‘Mauna Loa’ on the biofilter. SMCs among floors depending on the number of wicks were similar, and all regression lines of SMCs showed almost horizontal lines because of long-term stability on SMCs. Comparing plant growth parameters of S. wallisii ‘Mauna Loa’ before planting and at 30 days after planting on the biofilter, all growth parameters were not statistically significant. Thus, SMCs of the biofilter were more stabilized using this humidifying appar

This study was carried out to investigate the formaldehyde (FA) filtration pattern of additional media for indoor biofilter system. Dry pellet type activated carbon (PAC), activated clay (ACL), zeolite, diatomite, pumice and loess ceramic ball were tested. In the case of dry filter media, formaldehyde purification efficiency was the most excellent with activated clay and then was good with the activated carbon, diatomite, zeolite, and pumice order. PAC and ACL decreased the FA concentration with exponential pattern resulted from dynamic balance between emission and purification. Zeolite, diatomite, pumice, and loess ceramic ball showed high filtration rate at initial time and then increased FA concentration result from breakthrough. PAC, zeolite and diatomite could be recommended as additional filter media for biofilter system considering FA filtration and breakthrough characteristics. FA filtration and breakthrough characteristics were improved with wet media except PAC and ACL. In particular, purification performance improvement and breakthrough mitigation were higher in pumice and loess ceramic balls. PAC+ZEO mixing showed the most high purification performance and breakthrough mitigation in all mixing methods. Thus mixture of PAC with zeolite and vertical mixing could be recommended as additional filter media to improve the FA purification ability and pressure drop with indoor air biofilter system.

Biofilters are widely used for treating various types of wastewater and also recently in controlling non-point source (NPS) pollution including piggery stormwater. Gravels are common substrates employed in this type of biofilters. In this study, three parallel woodchip based biofilters with different thickness of woodchip layer were constructed and operated for about 300 days in 2013. Sampling was conducted every 2 days. The water temperature, pH, electric conductivity (EC), turbidity and DO were measured in situ. Other water quality parameters were analyzed in accordance with the Standard Methods for the Examination of Water and Wastewater (APHA et al. 1995). On one hand, with less woodchip media packed in the biofilter, better removal of TN, TP, NH4-N, TCOD was achieved. On the other hand, almost all NO3-N were removed regardless of the thickness of woodchip. In addition, with deeper thickness of woodchip media in the biofilter, more increased alkalinity and released organic matters were observed at the effluent. Alkalinity is important in biological nitrogen processes, especially in the reactions of ammonia transformation into nitrate (nitrification). Organic matters released from woodchip served as the carbon source to derive denitrification. It seems that only small amount of the woodchip were sufficient to achieve nice removal of nitrogen and phosphorus. Therefore, the amount of the woodchip could be a key in designing a woodchip biofilter.

바이오필터는 미생물의 대사작용을 통해 가스상 오염물질을 제거하는 생물학적 공정이다. 생물학적 공정은 친환경적이며, 2차 오염물질이 생기지 않기 때문에 악취가 발생하는 시설에 많이 적용되고 있다. 바이오필터의 운전성능 측면에서 충전담체는 매우 중요한 인자이다. 본 연구는 세라믹 재질의 담체를 Biofilter와 TBAB(Trickle Bed Air Biofilter)에 적용하여 암모니아를 대상으로 제거 특성을 확인하였다. 본 실험의 Biofilter와 TBAB는 995mL의 아크릴 소재로 제작된 반응기를 이용하였다. 세라믹 재질의 담체는 하수슬러지로 접종시킨 후 500mL를 반응기에 충전하여 실험을 실시하였다. 반응기에 유입되는 공기의 유량은 0.8L/min로 주입되었으며, 영양분은 7mL/day와 80mL/day로 Biofilter와 TBAB에 각각 하였다. 암모니아의 초기 농도는 142ppm(9.6g/m³･hr)으로 주입하였으며, 최대 320ppm(21.5g/m³･hr)까지 단계적으로 농도를 상승시켜 임계부하량 및 최대제거성능을 파악하였다. 유입 및 유출되는 암모니아는 인도페놀법을 이용하여 분석을 실시하였다. 바이오필터는 총 70일 동안 운전되었으며, 운전 후 세라믹 담체의 표면 변화를 확인하기 위하여 사용전의 세라믹 담체와 함께 SEM(Scanning electron microscope) 및 EDS(Energy Dispersive X-ray Spectroscopy)를 분석하였다. 본 연구의 실험결과 TBAB와 Biofilter는 운전초기에 불안정한 제거성능을 보였지만 TBAB의 경우 순응기간(15일)을 지난 후 99% 이상의 처리효율을 보여주었으며, Biofilter의 경우 93%의 처리효율이 확인되었다. 단계적으로 암모니아의 유입 농도를 상승시켜 주입한 결과 TBAB는 270ppm(18.1g/m³･hr)까지 98% 이상의 효율이 확인되었으며, 암모니아 농도를 320ppm(21.5g/m³･hr)으로 주입한 결과 처리효율이 94% 수준으로 낮아졌다. Biofilter의 경우 암모니아 농도 270ppm에서 82%의 처리효율이 확인되었으며, 암모니아 농도를 320ppm으로 상승시켜 주입한 결과 처리효율이 71%로 낮아졌다. 단계적인 농도 상승을 통해 세라믹이 충전된 TBAB와 Biofilter의 임계부하량(Critical load) 결과는 각각 13g/m³･hr와 6g/m³･hr이며, 최대제거성능(Elimination capacity)은 21g/m³･hr와 15g/m³･hr로 나타났다. 세라믹 표면을 SEM으로 관찰한 결과 TBAB와 Biofilter에 사용된 세라믹의 표면은 사용 전의 세라믹과 보다 상대적으로 거친 표면이 관찰되었으며, 표면의 성분 변화를 EDS로 확인한 결과 사용 전의 세라믹에서 확인되지 않은 성분인 인(P)이 확인되었다. 인은 미생물이 포함하고 있는 원소로 생물학적 반응기에 사용된 담체 표면에 생물막(Biofilm)이 형성되었기 때문에 세라믹 표면에 인의 성분이 확인되었다고 사료된다.