Earticle

본 연구에서는 합성섬유로 충진된 바이오필터(FBF)와 우드칩으로 충진된 필터(WBF)로 구성된 수직흐름형 습지공정(BFS)의 처리성능을 평가하였다. BFS 시스템에서 단독 필터를 사용한 것보다 두개의 필터를 직렬로 결합한 경우 특히 질소제거에 탁 월한 성능을 나타내었다. FBF 공정에서는 암모니아 질소 100%가 활발한 질산화 반응을 통하여 질산성 질소로 전환되었으며 후속 WBF에서 77%의 질산성 질소가 제거되어 우드칩이 제공하는 탄소가 탈질반응에 큰 영향을 끼치는 것으로 판명되었다. 바이오필터의 성능은 유입특성에 상관없이 독립적인 성능을 보였으며 인 제거에도 효과가 있었으나 종종 용출징후가 나타났으 며 현장적용시에는 이와 같은 사항을 유념해야할 것으로 보인다. 한편 회귀식 분석결과 운전시간에 따른 바이오 필터내부의 미생물 증식상태를 간접적으로 암시해 주었다. 본 연구결과 질소제거 측면에서 본 연구에서 제안하고 있는 여재를 이용한 수직 흐름형 직렬식 습지 공정은 전형적인 수직-수평흐름 습지와 비교하여 비용측면에서 많은 장점을 가지고 있다.

Two vertical flow biofilters in series (BFS) employing synthetic fiber (FBF) followed by woodchip (WBF) was investigated in order to assess its potential as an alternative to the typical vertical-horizontal flow configuration in removing nonpoint source pollutants specifically nutrients and organics. These lab-scale column biofilters were operated for 176 days alongside three other columns that were added for control and sampling purposes. The biofilter columns were fed with either a semi-artificial piggery stormwater or artificial stormwater with specific ammonia and nitrate contents. Results reveal that the BFS was more effective than a single biofilter in removing pollutants especially nitrogen. FBF was found to remove up to 100% of ammonia from the stormwater with corresponding increase in nitrate in the outflow which shows evidence of active nitrification. Meanwhile, the succeeding vertical WBF was able to subsequently remove 77% of the nitrate. The effective reduction of nitrate in a vertical flow biofilter was believed to be due to the use of woodchip which can provide a carbon source that is required for denitrification. However, further investigation is needed to support this claim. Nonetheless, the study shows the potential of vertical flow BFS as a nitrogen removal mechanism especially in areas where enough land space for horizontal flow biofilters is limited.

생물학적 고도처리공법은 수계에 유입되는 영양물질 제거에 상당한 효과를 거두고 있다. 그러나 고농도의 염분으로 생 물학적 처리 효율에 악영향을 미치는 음식물폐수, 수산물가공폐수, 매립지 침출수 등에 대한 연구는 거의 이루어지고 있 지 않는 실정이다. 본 연구에서는 Biofilter Process을 이용하여 염분을 함유하고 있는 폐수의 질산화에 미치는 영향을 염 분 농도, pH를 중심으로 검토하였다. 그 결과, 염분 농도 2,000~55,000 mg·NaCl/L에서는 질산화가 염분의 영향을 받지 않는 것으로 나타났으나, 염분 농도 80,000 mg·NaCl/L에서는 질산화율이 11.4%에 그쳐 상당한 영향을 받는 것으로 나타 났다. NaCl 30,000 mg/L, T-N 500 mg/L의 조건하에서 질산화에 미치는 pH의 영향을 검토한 결과, 중성영역의 경우 질 산화 반응으로 인한 반응기의 pH가 약 6이하로 감소되고 질산화율이 약 50% 이하를 나타내었다. 염기성영역의 경우는 질산화 반응에도 불구하고 반응기의 pH는 약 7.0으로 유지되고 질산화율이 약 80% 이상으로 나타났다. 산성영역의 경 우에는 반응기의 pH가 크게 감소하고 질산화도 거의 이루어지지 않았다. 한편, 운전기간 동안 pH를 중성영역으로 조절 한 결과 질산화 효율이 99%이상으로 높은 값으로 나타났다. 이상의 결과로 부터 운전기간 동안에 중성이상의 pH로 유 지하는 것이 질산화에 효과적인 것을 알았다.

Biologically advanced treatment process is widely used for high concentration wastewater treatment, and it has a considerable effect on the removal of nutrients flowing into the water environment. However, the research for food wastewater, fish processing wastewater, landfill leachate and the like, their high salinity adversely affecting the biological treatment efficiency, has rarely been conducted. This study investigated the influence of salinity on the nitrification of wastewater carrying high organic concentration using the Biofilter Process. Nitrification was not affected with low salinity concentration of 2,000~55,000 mg·NaCl/L, however, it was affected with salinity concentration of 80,000 mg·NaCl/L, resulting the reduction of nitrification rate to 11.4%. The initial neutral pH of the wastewater, including NaCl 30,000 mg/ L and TN 500 mg/L, dropped to 6 or less as nitrification went along and reduced to 50%. In the case of basic region, the pH of the reactor was maintained at about 7.0 despite the nitrification reaction and the nitrification rate was about 80% or more. In the acidic region, the pH of the reactor was greatly decreased and nitrification was hardly achieved. As the pH level during the operation period was adjusted to the neutral region, the nitrification efficiency was higher than 99%. It could be postulated that for the effective nitrification, the pH of influent water needed to be adjusted to neutral or higher and maintained during nitrification process.

Absorbent Biofilter Systems (ABS), composed of an anaerobic septic tank, a pump chamber and an absorbent biofilter tank, have been found to economically provide rural on-site wastewater treatment. This study was conducted to assess the potential of ABS effluent as an alternative water resource for agricultural and environmental use, with respect to the removal of pathogenic microorganism and their fertilization effect. A pilot scale ABS was used to compare its removal efficiency of pathogens from effluent water. Overall, more than 95 percent of Salmonella and E. coli were removed. This result demonstrates that a significant reduction in the pathogenic microorganism of effluents can occur in ABS, which implies the feasibility for the use of ABS effluent in agriculture and environment, with the provision of a further simple disinfection step, in order to satisfy the WHO guidelines for the microbiological quality in agriculture. In addition, because of the abundant nutritional content of ABS effluent, the substitution effect of fertilizer (N, P and K) in paddy irrigation, i.e. 2/3 for nitrogen, l/3 for phosphorus and 1/5 for potassium would be expected. Based on the experimental data, the ABS effluent could be used as a new alternative water resource for paddy irrigation, as well as for environmental purposes, such as supplying water to ecological parks in rural villages.

Objectives: This study was conducted to investigate the removal of high odor concentration from swine wastewater treatment facility by full scale biofilter using liquid with deodorant mixed with earthworm cast and distillery sludge. Methods: The supply of the culture liquid to the microorganism on the media in the biofilter increases the activity and growth of biomass. The experimental equipment was biofilter tower with treatment capacity of 90 m 3/min. The experimental conditions included gas flow of $60m^3/min$, retention time of 20 sec, and gas/liquid ratio of 67. Results: With changing season from winter to summer, the inlet odor concentration of ammonia increased from 2.5 ppm to 29 ppm, and of hydrogen sulfide from 21 ppm to 91 ppm, respectively. The odor treatment system with biofilter using the culture liquid was stable when the high loading rate increased and showed excellent removal grade with an average of 96.7% for ammonia, and an average of 93.7% for hydrogen sulfide. The pH and SCOD in the recirculating culture liquid near the bottom of the biofilter tower decreased with operation time, but its influence on the odor removal rate was negligible, because the organic matter (SCOD) was replaced by some culture liquid supplied 2-4 times per day. Conclusions: The biofilter using culture liquid could successfully remove high odor concentration which was generated from swine wastewater treatment facility.

This study was performed to evaluate the need for heating wastewater to enhance treatment efficiency of organic matter (BOD, SS) during cold winter in newly developed Absorbent Biofilter System (ABS) which was established in the Suwon Campus of the Seoul National University. Treatments consisted of non-heating (2000 year) and heating(2001, 2002 year), and sampled data were analyzed during cold winter period as well as post winter period to investigate the influence of heating after winter season. Even the average air temperature showed only $0.4^{\circ}C$ difference between two experimental years, the difference in the average effluent temperature during cold winter period between heating and non-heating experiment was approximately $11^{\circ}C$. The average effluent concentration of organic matter in non-heating treatment exceeded the Korean standards for water quality of discharged effluent in riparian area (BOD and SS 10 mg/L); however, the standards were met in case of heating treatment during both winter and post winter period. Therefore, the need fur heating wastewater during cold winter season in ABS was justified. On the other hand, there was no improvement of treatment efficiency in T-N and T-p, but we observed the more activated nitrification as increasing the wastewater temperature. Because the average underground temperature was $5^{\circ}C$ higher than the average air temperature during cold winter period, we recommend that the ABS can be established in the underground rather than on-ground for saving the heating cost.

A pilot study was performed to examine the feasibility of UV disinfection system and the reactivation of indicator microorganisms (TC, FC, E. coli) after UV irradiation for agricultural reuse of reclaimed water. Photoreactivation and dark repair enable UV-inactivated microorganisms to recover and may reduce the efficacy of UV inactivation, which might be drawbacks of the UV disinfection method. The effluent of biofilter for 16-unit apartment house was used as input to the UV disinfection system, and average SS and BOD concentration were 3.8 and 5.7 mg/L, respectively, and the mean level of total coliform was in the range of $1.0\times10^4$ MPN/100mL. UV disinfection was found to be effective and it reduced mean concentration of indicator microorganisms (total coliform, fecal coliform, and E. coli) to less than 100 MPN/100mL within 60s exposure using 17, 25, and 40W lamps. Two UV doses of 6 and 16 mW$\cdot$s/$\textrm{km}^2$ were applied and microorganisms reactivation was monitored under the dark, photoreactivating light, and solar irradiation. Microorganisms reactivation was observed in the UV dose of 6 mW$\cdot$s/$\textrm{km}^2$, and numbers increased up to 5% at the photoreactivating light and 1% at the dark. However, microorganisms were inactivated rather than reactivated at the solar radiation and numbers decreased to non-detectible level about below 2 MPN/100mL in 4 hours. In the case of 16 mW$\cdot$s/$\textrm{km}^2$, microorganism reactivation was not observed indicating that UV dose might affect the reactivation process such as photoreactivation and dark repair. Therefore, concerns associated with microorganism reactivation could be controlled by sufficient UV dose application. Agricultural reuse of reclaimed water might be even less concerned due to exposure to the solar irradiation that could further inactivate microorganisms. The pilot study result is encouraging, however, sanitary concern in water reuse is so critical that more comprehensive investigation is recommended.

Air pollution posed a public concern to communities in a global scale. Hence, this study explored the potential of coconut spathe fibers as air filter media in order to reduce pollution level. Coconut spathe fibers (CSF) were cleaned and cut to 7cm by 7cm of thickness 0.5cm. Air filters were made up of the coconut pouch sandwiched between two metal plates. Metal plates were ridden with evenly distributed 1cm diameter holes and 1cm apart. Filters were constructed in triplicates and tested against air pollution. The free-acceleration test for in-use compression-ignition motor vehicles based on European Emission Standards pursuant to Section 21 of Republic Act 8749 (Philippine Clean Air Act of 1999) was employed. Smoke Opacity Measurement (SOM) was done to the assess air quality before and after filtration as a function of thickness using the free acceleration principle. Light- absorption coefficient () of the exhaust gases was measured with a digital opacimeter. Three replications were done. Mean values were reported and statistically analyzed using SPSS software. Test was performed to quantify the amount of air pollutants that impair visibility, including aerosols and particulate matters, in the gaseous exhaust.. Results suggest that car exhaust smoke after passing through CSF filters became relatively transparent light. This study illustrates the potential of coconut spathe fibers as an alternative natural air filter system for air pollution control.

A bacterial strain isolated from a compost-packed biofilter after 100 days of operation was identified as Rhodococcus pyridinovorans PYJ-1, with a similarity of 99%. This strain removed benzene, toluene and m-xylene (BTX) at 2～30 mg/L within 6～20 hrs in batch cultures. Optimum pH and temperature for BTX removal were pH 7 and 32℃. This strain also removed a mixture of BTX at component concentrations of 2～5 mg/L.

In this study, two integrated system, composed of UV-photocatalytic reactor loaded with different photocatalyst media and fluidized biofilter in series, were constructed to compare their efficiency for the treatment of real textile wastewater. The real textile wastewater containing various dyes, surfactants, polyvinyl alcohol(PVA), hydrolyzed polyester and other recalcitrant organic substances, was fed to a fluidized biofilter, after which the fluidized biofilter-treated wastewater entered into UV/photocatalytic process. The return-sludge obtained from a textile wastewater treatment facility located in Daegu, was immobilized at the fluidized media in the biofilter and the photocatalytic reactor was filled with TiO2 coated-1) porous silica media or 2) glass bead media. For the case of TiO2 coated-porous silica media, the COD values of feed, biofilter-treated wastewater and the effluent from photocatalytic reactor were 1800ppm, 350-380ppm and 200-300ppm, respectively. For the case of TiO2 coated-glass beads media, the COD values of feed, biofilter-treated wastewater and the effluent from photocatalytic reactor were 1800ppm, 350-380ppm and 315-340ppm, respectively. Thus the COD removal efficiency of the integrated system with TiO2 coated-porous silica bead media was maintained at 83-89% while the COD removal efficiency of the integrated system with TiO2 coated-glass bead media was maintained at 79-86%. Moreover, for the case of TiO2 coated-porous silica media, the ADMI color values of feed, biofilter-treated wastewater and the effluent from photocatalytic reactor were 1300, 500-630 and 230-550ppm, respectively. For the case of TiO2 coated-glass bead media, the ADMI color values of feed, biofilter-treated wastewater and the effluent from photocatalytic reactor were 1300, 500-630 and 550ppm, respectively. Thus the color removal efficiency of the integrated system with TiO2 coated-porous silica bead media was maintained at 58-82% while the color removal efficiency of the integrated system with TiO2 coated-glass bead media was maintained at 58%. It is suggested that the type of TiO2 coated-media is important to determine the characteristics on the whole integrated system

본 연구에서는 신 개념의 바이오필터 시스템인 RDBF를 이용하여 기상의 styrene을 제거하고자 하였다. 다양한 운전조건에서 시스템의 성능을 평가하고, 진공흡입을 통해 과다성장 미생물을 제어하고자 하였다. RDBF에서는 sheet 형태의 충진 담체를 사용하므로 영양원 및 공기의 균일한 공급이 가능하였고, 빠른 속도로 균일한 미생물 층을 담체 표면에 형성할 수 있었다. 또한 기-액 접촉면적을 증대 시켜 95% 이상의 안정적이고 높은 styrene 분해 효율과 125g/m3․h의 높은 제거 용량을 가질 수 있게 해주었다. 하지만 우수한 성능은 미생물의 과다성장에 따른 기공의 폐쇄현상 때문에 오래 지속되지 않았고 반응기의 성능과 안정성은 급속히 저하되었다. 이를 해결하기 위해 진공흡입을 통한 미생물 제거를 시도하였으나 제한적인 효과만을 확인하였다. 향후 RDBF 반응기의 상업화를 위해서는 보다 효율적인 미생물 제어 방법이 개발될 필요가 있다.

A new type of biofilter, a rotating drum biotrickling filter (RDBF), was developed and operated for the removal of styrene from industrial waste gas. The porous polyurethane foam sheet was used as a packing materials for the RDBF and a pure culture of Gram-positive bacterium Brevibacillus sp. SP1 was used as an inoculum. The reactor showed a short start-up period of 18 days, during which uniform biofilms were developed on the packing. During a steady operation at an incoming styrene concentration of 200 ppmv and a retention time of 0.5 min, a high and stable removal of styrene over 95% was observed. The maximum elimination capacity was estimated to be 125 g/m3․hr. The outstanding performance was attributed to an efficient gas-liquid mass transfer and the appropriate supply of nutrient solution to the biofilm microorganisms on the packing by the rotation of the drum.

휘발성 황화합물 중 생물학적으로 가장 난분해성으로 알려져 있는 DMS에 대한 분해능이 우수한 신균주를 분리․동정하여 Gordonia sihwaniensis PKL-1로 명명하였다. 이 균주는 DMS 초기농도가 35 mg/L 이상일 때에도 우수한 분해능을 보였고, 회분식 배양에서 최대 비분해속도 는 0.0016 mg/(mg-protein)․hr이었고, 최적의 온도와 pH는 각각 25℃와 pH는 7이였다.

Biodegradation of dimethyl sulfide (DMS) was studied in a batch culture using Gordonia sihwaniensis PKL-1 isolated from a compost biofilter after 100 days of operation for the removal of volatile organic compounds. Optimal pH and temperature for the removal of DMS were 7 and 25°C, respectively. The Michaelis-Menten kinetic constants for DMS removal,  and  , were 0.0016 mg/(mg-protein)․hr, and 8.05 mg/L, respectively.