• Journal of Microbiology and Biotechnology
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• 제29권1호
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• pp.91-104
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• 2019

The taxonomic and functional characteristics of bacterial communities in the pre-chlorinated rapid filters and ozonated biological activated carbon (BAC) filters were compared using Illumina MiSeq sequencing of the 16S rRNA gene and community-level physiological profiling (CLPP) based on sole-carbon-source utilization patterns. Both the rapid filters and BAC filters were dominated by Rhizobiales within ${\alpha}-proteobacteria$, but other abundant orders and genera were significantly different in both types of filter. Firmicutes were abundant only in the intermediate chlorinated rapid filter, while Acidobacteria were abundant only in the BAC filters. Bacterial communities in the rapid filter showed high utilization of carbohydrates, while those in the BAC filters showed high utilization of polymers and carboxylic acids. These different characteristics of the bacterial communities could be related to the different substrates in the influents, filling materials, and residual disinfectants. Chlorination and ozonation inactivated the existing bacteria in the influent and formed different bacterial communities, which could be resistant to the oxidants and effectively utilize different substrates produced by the oxidant, including Phreatobacter in the rapid filters and Hyphomicrobium in the BAC filters. Bradyrhizobium and Leptothrix, which could utilize compounds adsorbed on the GAC, were abundant in the BAC filters. Ozonation increased taxonomic diversity but decreased functional diversity of the bacterial communities in the BAC filters. This study provides some new insights into the effects of oxidation processes and filling materials on the bacterial community structure in the biological filters of drinking water treatment plants.

• 한국환경과학회지
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• 제16권6호
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• pp.671-675
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• 2007

The objective of this study was to clarify the characteristics of the removed micropollutant since the breakthrough of adsorption ability was occurred in biological activated carbon(BAC) process. The removal efficiency of DOC (Dissolved Organic Carbon) was 36 % in the breakthrough of BAC occurred by NOM (Natural Organic Matter). The most of removal DOC was found out the adsorbable and biodegradable DOC (A&BDOC). But it was not clear to remove by any mechanism because A&BDOC have simultaneously the adsorption of activated carbon and biodegradation by microorganism in BAC. The removal of bromophenol was examined with BAC and rapid sand filter, for investigation of DOC removal mechanism in the breakthrough of BAC. In this experiment, BAC filter has been operated for 20 months for the treatment of reservoir water. The BAC filter was already exhausted by NOM. Bromophenol, adsorbable and refractory matter, was completely removed by BAC filter. Therefore, it might be removed by the adsorption in BAC. Adsorption isotherms of bromophenol were compared to two BACs which was preloaded with 500 daltons and 3,000 daltons of NOM. BAC preloaded with 3,000 daltons of NOM was not decreased to the adsorbability of bromophenol but BAC preloaded with 500 daltons of NOM was greatly decreased to it. These result indicated that NOM of low molecular weight can be removed by adsorption after a long period of operation and the breakthrough by NOM in BAC. Therefore, micropollutants might be removed through adsorption by saturated BAC.

• 환경위생공학
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• 제17권4호
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• pp.47-52
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• 2002

This study was carried out to examine the characteristics of dual media filter with BAC and sand on a pilot scale which was installed in T Water Treatment Plant of Seoul. The conclusions drawn from experimental results are as follows : For the BAC-Sand filter, the preceded gravity sand filter did not largely affect the removal of organics and turbidity causing matters, tut the frequency of backwashing was explicitly reduced to two times with the stable growth of microorganisms. The biomass on media in case of existence of preceded sand filter was 1.4 times higher than that of nonexistence. In case of backwashing with water, the time needed to comply with below 10NTU took 22, 10, and 5 minutes respectively with the expansion ration of 1.2, 1.5 and 1.8. The higher the expansion ration was, the shorter the backwashing time was.

• 상하수도학회지
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• 제9권4호
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• pp.107-114
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• 1995

The raw drinking water quality is getting worse because of the winter drought and the conventional treatment system is'nt suitable to obtain the satisfied quality of water. So, the advanced water system, BAC(Biological Activated Carbon) process is said to be effective to remove dissolved organics and ammonia nitrogen. In our study, the BAC pilot plant using Nak-dong river water is tested in low temperature. Following results are found from the study. The ammonia nitrogen removal rate of BAC system using wood-based carbon (PICABIOL) was 99% in $6^{\circ}C$ temperature. Chlorine dosage in wood-based BAC effluent was reduced to 67% of that in sand filtered wate. It resulted from the removal of ammonia nitrogen. Also, THM formed by chlorine addition in wood-based BAC effluent was decreased to 65% of that in sand filtered water. In the case of dual-filter, the removal efficiency of ammonia nitrogen was increased 30% more than in conventional sand filter. According to this result, the ammonia nitrogen load to BAC system could be lessened by the use of dual-filter.

• 대한환경공학회지
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• 제31권5호
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• pp.378-381
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• 2009

본 연구에서는 BAC 공정을 장기간 운전하면서 유입수중의 $Br^-$ 농도변화에 따른 THMFP 제거율을 평가하였다. BAC 공정을 장기간 운전하면서 THMFP 구성종별로 제거능을 살펴본 결과, $CHCl_3$ 생성능의 경우는 계절변화에 따른 유입수중의 $Br^-$ 농도변화에 따라 관계없이 우수한 제거능을 나타내었으나, 브롬계 THM 생성능의 경우는 유입수중의 $Br^-$/DOC 비가 증가할수록 제거율은 저하되었다. 또한, BAC 공정에서의 THMFP 구성종별로 제거특성을 살펴본 결과, 유입수의 $Br^-$/DOC 비가 높은 경우에 EBCT가 증가할수록 $CHCl_3$ FP의 제거율은 증가하였으나 브롬계 THMFP의 경우는 EBCT가 증가할수록 감소하는 경향을 나타내었고, THMFP 구성종의 브롬원자 개수가 많아질수록 제거율은 감소하였다.

• 한국환경과학회지
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• 제24권12호
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• pp.1551-1558
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• 2015

In Korea, many drinking water treatment plants (DWTPs) have introduced and are going to introduce biological activated carbon (BAC) process to treated dissolved organic matter (DOM) in water which are difficult to control by conventional water treatment processes. Even though more decade have passed since introduced BAC in Korea, most of BAC operating method was followed to the modified sand filter operating manuals. In case of BAC backwashing, many DWTPs set the periods of backwashing about 3~5 days. In this study, we have collected data to set the proper BAC backwashing periods from both pilot-plant and real DWTPs. We had measured heterotrophic plate count (HPC), turbidity, water temperature, dissolved organic carbon (DOC) and headloss from just after backwashing to the next backwashing time for two years. Considering water quality factors, the BAC run time from backwashing to the next backwashing could extend more 30 days without water quality deterioration if the head loss do not reach the limited level which depends on each BAC facilities' condition. It means the BAC treated water could be saved in the proportion of extended the backwashing period to the existing backwashing period.

• 한국환경과학회지
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• 제23권6호
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• pp.1101-1109
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• 2014

In this study we followed biofilm formation and development in a granular activated carbon (GAC) filter on pilot-scale during the 12 months of operation. GAC particles and water samples were sampled from four different depths (-5, -25, -50 and -90 cm from surface of GAC bed) and attached biomass were measured with adenosine tri-phosphate (ATP) analysis and heterotrophic plate count (HPC) method. The attached biomass accumulated rapidly on the GAC particles of top layer throughout all levels in the filter during the 160 days (BV 23,000) of operation and maintained a steady-state afterward. During steady-state, biomass (ATP and HPC) concentrations of top layer in the BAC filer were $2.1{\mu}g{\cdot}ATP/g{\cdot}GAC$ and $3.3{\times}10^8cells/g{\cdot}GAC$, and 85%, 83% and 99% of the influent total biodegradable dissolved organic carbon ($BDOC_{total}$), $BDOC_{slow}$ and $BDOC_{rapid}$ were removed, respectively. During steady-state process, biomass (ATP and HPC) concentrations of middle layer (-50 cm) and bottom layer (-90 cm) in the BAC filter were increased consistently. Biofilm development (growth rate) proceed highest rate in the top layer of filter (${\mu}_{ATP}=0.73day^{-1}$; ${\mu}_{HPC}=1,74day^{-1}$) and 78%~87% slower in the bottom layer (${\mu}_{ATP}=0.14day^{-1}$; ${\mu}_{HPC}=0.34day^{-1}$). This study shows that the combination of different analytical methods allows detailed quantification of the microbiological activity in drinking water biofilter.

• 대한환경공학회지
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• 제31권4호
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• pp.308-323
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• 2009

생물활성탄 공정은 정수처리에서 획기적인 공정으로 평가받고 있으며, 전 세계적으로 많은 정수장에서 BAC 공정을 채택하여 운전하고 있다. BAC 공정의 장점은 활성탄에 흡착된 오염물질들이 활성탄 표면에서 서식하고 있는 다양한 미생물 집합체(생물막)에 의해 생물분해되어 자연적으로 활성탄의 재생이 이루어져 활성탄 사용기간의 연장을 유도하여 정수처리 비용을 감소시킬 수 있다는 것이다. 또한, 유입수중의 생분해 가능한 유기물질들을 제거하여 배 급수관망에서 미생물의 재성장을 억제하는데 탁월하다. 그러나 BAC 공정의 효율이 활성탄 표면에 형성되어 있는 생물막에 의해 제한되어지는 문제점도 있다. 본 논문에서는 GAC에서 BAC로의 전환, BAC 생물막의 특성, 오염물질의 제거 메카니즘, BAC 공정에 영향을 미치는 인자들, BAC 공정의 제어 및 BAC 공정의 모델링에 대해 크게 여섯 부분으로 상세하게 기술하였다.

• 한국물환경학회지
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• 제18권4호
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• pp.355-363
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• 2002

A demonstration plant was carried out to investigate the removal efficiency of $NH_3-N$ and $KMnO_4$ consumption depending on the existence of pre-chlorination for the ozonation and activated carbon process in the S water treatment plant which is located at the middle of Keum River. The averge removal efficiency of $KMnO_4$ consumption for $O_3/GAC$ processes with pre-chlorination and $O_3/BAC$ processes without pre-chlorination were 48.6% and 50% respectively. It is similar to removal effect of $KMnO_4$ consumption for GAC and BAC process depending on the existence of pre-chlorination. Otherwise, the removal of THMFP for GAC and BAC process was 58% and 68% respectively. $NH_3-N$ was not almost removed by sand filter and ozonation, but the average removal efficiency in the BAC process was about 31%. Especially, $NH_3-N$ was not almost removed by $O_3/BAC$ processes at the low temperature (below $$10^{\circ}C$$) in the winter season, $O_3/BAC$ processes have the advantage of removal of organic substance when it is compared to pre -chlorination followed by $O_3/GAC$ processes. Pre-chlorination followed by $O_3/GAC$ processes were required to remove $NH_3-N$ in the winter season because the removal of $NH_3-N$ was almost ineffective by $O_3/BAC$ process.

• 상하수도학회지
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• 제23권2호
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• pp.189-198
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• 2009

Tastes and odor in water caused by geosmin and 2-MIB are the major customer complaints for water utilities. Therefore, control of geosmin and 2-MIB is a worldwide concern. In this study, the effects of biofilter media type (three different activated carbons and anthracite), empty bed contact time (EBCT) and temperature on the removal of geosmin and 2-MIB in BAC filters were investigated. Experiments were conducted at three different water temperatures (5, 15 and $25^{\circ}C$) and four different EBCTs (5, 10, 15, and 20 min). The experimental results indicated that the coal based BAC retained more bacterial biomass on the surface of the activated carbon than the other BACs, and increasing EBCT or increasing water temperature also increased the geosmin and 2-MIB removal in BAC filters. To achieve above 50% of removal efficiency for geosmin and 2-MIB in a BAC filter, above 10 min EBCT at $5^{\circ}C$ and 5 min EBCT at above $15^{\circ}C$ were required. The kinetic analysis for the biodegradation of geosmin and 2-MIB indicated a first-order reaction rate at various water temperatures. Data obtained from the BAC filters at various temperatures were also used to evaluate pseudo first-order rate constants for geosmin and 2-MIB. The half-lives evaluated at 5, 15, and $25^{\circ}C$ for geosmin and 2-MIB ranged from 2.39 to 10.31 min and 3.35 to 13.97 min, respectively, which can be used to assist water utilities in designing and operating BAC system.