Abstract
In this study, three different biological activated carbons (BACs) were prepared from activated carbons made of each coal (F400, Calgon), coconut (Samchully) and wood(Pica, Picabiol) which were run for two and half years in the pilot plant. The attached bio-film microorganisms in and on the BACs were isolated and identified. The results showed that nine different bacteria species (Chryseomonas luteola, Stenotrophomonas maltophilia, Pseudomonas vesicularis, Aeromonas hydrophila, Spingomonas paucimobilis, Agrobacterium radiobacter, Pseudomonas fluorescens, Spirillum spp., and Pasteurella haemolytica) were isolated and identified, the dominant species was Pseudomonas sp. that had occupied 56.5%. More specifically, it was observed that the populations of the microorganisms deceased in the order: Pasteurella haemolytica (18.9%) > Chryseomonas luteola (4.0%) > Agrobacterium radiobacter (3.5%) > Aeromonas hydrophila (2.0%) in and on the BACs. After isolating of 9 species of biofilm microorganisms, the growth curve for the biomass was investigated. During 24~96 hours, the biomass has the highest concentration, and activity of the biomass was the best to uptake geosmin as carbon resources. The operation temperatures for investigating the biodegradation of geosmin were set at $4^{\circ}C$ and $25^{\circ}C$. Pseudomonas vesicularis, Pseudomonas fluorescens, Agrobacterium radiobacter and Stenotrophomonas maltophilia played a maior role in removing the target compound as geosmin. However, geosmin was not biodegraded well by Chryseomonas luteola, Spingomonas paucimobilis, and Spirillum spp.. It is also interesting to evaluate kinetics of biodegradability of geosmin. The first-order rate constants for biodegradability of geosmin at $4^{\circ}C$ and $25^{\circ}C$ were $0.00006{\sim}0.0002\;hr^{-1}$ and $0.0043{\sim}0.0046\;hr^{-1}$ respectively. Higher water temperature produced better geosmin removal rates. When concentrations of geosmin increased from 10 to 10,000 ng/L, the rate constants for biodegradability of geosmin increased from 0.0003 to $0.0882\;hr^{-1}$. As described earlier, higher geosmin concentration in the reactor produced higher rate constant.
3가지 재질의 생물활성탄 부착 박테리아들을 부리 동정한 결과 총 9종류의 부착 박테리아가 동정되었다. Pseudomonas 속이 차지하는 비율이 평균 56.5%로 나타나 가장 높은 우점비율을 나타내었고, 다음으로 Pasteurella속 18.9%, Chryseomonas 속 4.0%, Agrobacterium속 3.5%, Aeromonas속 2.0% 순으로 검출되었다. 순수 분리된 9종의 박테리아들의 성장곡선을 조사한 결과 24~96시간 내에 최대의 생체량을 나타내어 geosmin을 유기탄소원으로 활용하는 능력이 뛰어난 것으로 조사되었다. $4^{\circ}C$와 $25^{\circ}C$의 운전조건에서 geosmin에 대한 생분해능을 조사한 결과 Pseudomonas vesicularis, Pseudomonas fluorescens, Agrobacterium radiobacter 및 Stenotrophomonas maltophilia 등이 뛰어난 생분해율을 나타낸 반면 Chryseomonas luteola, Spingomonas paucimobilis, Spirillum spp. 등은 비교적 낮은 geosmin 생분해능을 나타내었다. Geosmin의 생분해능은 수온이 $4^{\circ}C$일 경우 생분해율 속도상수가 $0.00006{\sim}0.00020\;hr^{-1}$의 범위에서 $25^{\circ}C$에서는 $0.0043{\sim}0.0046\;hr^{-1}$의 범위로 나타나 수온 상승에 따라 큰 폭으로 증가하였으며, 또한 투입된 geosmin의 농도가 10~10,000 ng/L로 증가할수록 생분해율 속도상수도 $0.0003{\sim}0.0882\;hr{-1}$로 증가하였다.
