• Journal of Korean Society on Water Environment
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• v.20 no.4
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• pp.357-364
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• 2004

In this study, biodegradable organic matter was divided into a rapidly biodegradable fraction($BDOC_{rapid}$) and a slowly biodegradable fraction($BDOC_{slow}$) for various waters with different types of DOC. These fractions($BDOC_{rapid}$ and $BDOC_{slow}$) were defined by using a shaking incubation method modified from Carlson's method. Also, in this study, optimum incubation time and accuracy were investigated to determine $BDOC_{rapid}$ and $BDOC_{slow}$. When suspended bacteria obtained from raw water and BAC effluent, or attached bacteria from BAC was respectively used as an inoculum, the difference in total BDOC($BDOC_{total}$) was minimal. Therefore, total BDOC was determined in 7~8 days by the shaking method, which is comparable with Servais's method by which BDOC was determined in 28 days. In addition, the difference of BDOC between these two methods was within 7%. Although $BDOC_{rapid}$ and $BDOC_{slow}$ were effectively determined by a method defined by Klevens, the difference in optimal incubation time was significant for different water samples. However, when using the shaking method, optimal incubation time for $BDOC_{rapid}$ was found to be 3 days, therefore, the $BDOC_{rapid}$ was defined as the difference between $DOC_0$ and $DOC_{3days}$, and $BDOC_{slow}$ was defined as the difference between $BDOC_{total}$ and $BDOC_{rapid}$. As a conclusion, for determining the fraction of BDOC using the shaking method, the concentrations of an inoculurns and optimal incubation times used in this study were very effective.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.12
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• pp.1274-1279
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• 2006

The formation characteristics of $BDOC_{rapid}$ and $BDOC_{slow}$ with different ozone dosages for 3 different kinds of waters from Maeri raw water in the down stream of Nakdong river, Hoidong reservoir water in Busan City and treated Maeri raw water(sand filtered) has been investigated in this study. The ozone dosages for producing maximum $BDOC_{total}$ in the Maeri raw water, Hoidong reservoir water and sand filtered water of Maeri were 0.9, 1.1 and 1.4 $mgO_3$/mgDOC respectively. It could be concluded that the ozone dosages for formations of maximum $BDOC_{total}$ were determined by characteristics of water. The ozone dosages for producing maximum $BDOC_{rapid}$ in the Maeri raw water, Hoidong reservoir water and sand filtered water of Maeri were 0.9, 0.9 and 1.0 $mgO_3$/mgDOC respectively that were same or lower than the used ozone dosages for producing maximum $BDOC_{total}$. $BDOC_{slow}$ was being formated and increased continuously with the higher ozone dosages which were the used ozone dosages for maximum formation of $BDOC_{total}$ and $BDOC_{rapid}$. For the best results of a pre-treatment of biofiltration, the optimum ozone dosage ranges in formation of $BDOC_{rapid}/BDOC_{total}$ were $0.6{\sim}1.0\;mgO_3$/mgDOC that were lower than the ozone dosage ranges of $0.9{\sim}1.4\;mgO_3$/mgDOC for the maximum formation $BDOC_{total}$. The reported results indicated that the best and effective ways from economic and technical points of view to determine the optimum ozone dosages of the pretreatment of biofilteration process were investigating and classifying BDOC.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.10
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• pp.909-918
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• 2009

As a part of dissolved organic matter, dissolved organic carbon (DOC) or biodegradable DOC (BDOC) fraction in particular is one of important issues in water treatment. Due to role as a nutrient source for bacteria, BDOC, therefore, may cause regrowth problems in water distribution system. The main objectives of this study were to investigate the possibility to minimize the concentration of BDOC in advance water treatment process. DOC in water is fractionized into four fractions such as AnBDOC (adsorbable and non-biodegradable DOC) which possesses adsorption properties but no biodegradation ability; nABDOC (biodegradable and non-adsorbable DOC) which has biodegradation properties but no adsorption ability; ABDOC (adsorbable and biodegradable DOC) which has adsorption properties and biodegradable characteristic; and non-removal DOC (nAnBDOC) which do not have either adsorbability or biodegradability. BAC process was effective for adsorbable DOC (AnBDOC+ABDOC) removal. However, in some cases, the removal ratio of adsorbable DOC was not sufficient. BDOC removal rate is very low or irremovable. Thus, for the control of residual DOC, it is necessary to change the operation condition by BAC process. From the analysis results of DOC fractions, water treatment processes appeared to be effective because it could grasp a remarkable amount of biodegradable, adsorbable and non-removal DOC. The concentration of AOX in non-prechlorination process was reduced from 7.1 ${\mu}g$/L to 0.51 ${\mu}g$/L in BAC process followed by ozonation.

• Journal of environmental and Sanitary engineering
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• v.16 no.3
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• pp.34-41
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• 2001

It is well known that bioassay on the low organic matters in water have developed from the two methods. One is assimilable organic carbon(AOC) that makes use of the maximum growth biomass of the pure strains for the standard substrates, the other is biodegradable dissolved organic carbon(BDOC) that determines the fraction of dissolved organic carbon(DOC) available for microbial utilization. The purpose of this study was to upgrade the measurement method of BDOC in natural water or drinking water. BBOC was determined by means of the bacterial growth and the DOC decrease at the same time. The origin inoculums were used to the suspended bacteria from Han River water, The initial optimum biomass and incubation time for initial DOC were induced by variation of nutrient repression and inoculums. The time reached to minimum DOC was selected as incubation time. The initial optimum biomass for Han river water was about 1000~5000 CFU/mL, respectively. In a sufficient biomass, suitable incubation time was about 3~5 day. It was indirectly calculated BDOC on maximum growth rate by measuring growth yield of indigenous bacteria. But it was difficult to adapt growth yield coefficient because of irregular bacterial growth. The measured 3 day BDOC was close to BDOC calculated with our proposed experimental equation between DOC and BDOC. It shows that the quantification of BDOC with this experimental equation can be used indirectly.

• Journal of Korean Society of Water and Wastewater
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• v.12 no.3
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• pp.21-29
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• 1998

The ozone/GAC process, sometimes termed BAC(Biological Activated Carbon) appeared to be effective for the removal of soluble organic matters in the drinking water Chabrol is a simple model for the simulation like as the variation of HPC and BDOC in the BAC tower. This study were carried out to calibrate of HPC and BDOC and to evaluate $H_1$ and $H_2$ of ozone-treated water with Chabrol model. BDOC values of the ozone-treated water and BAC effluent are analyzed using method of Levi and Joret. As the ozone-treated water and BAC Effluent are incubated, the HPC are increased up to 0.24 mgC/l and 0.09 mgC/l respectively. $H_1$ and $H_2$ of the ozone-treated water is 0.3 mgC/l and 0.349 mgC/l respectively and Chabrol model for BAC tower can be calibrated.

• 수도
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• v.24 no.4 s.85
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• pp.79-87
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• 1997

In an effort to prevent the formation of DBPs from disinfection and the microbial regrowth in distribution systems, the ozonation followed by biological filtration process in drinking water treatment train has been recently developed as an alternative process to reduce effectively water-born organic matter as precursor. There are, however, insufficient for the consistent information and data about the relation between ozone dosage based on organic surrogate parameter, TOC or DOC and effect of ozonation on BDOC formation. This study is to review critically for the effect of ozonation on biodegradability on the basis of published technical papers including the output from author's research laboratory. It truned out that : 1. ozonation in the presence of organic matter has a tendancy to increase in BDOC content, 2. the rate of BDOC formation was maximum below 1mg $O_3/mg$ DOC of ozone dose, but about maximum content of BDOC was obtainable at the range from 1.5mg $O_3/mg$ DOC to 2mg $O_3/mg$ DOC, 3. from above 1mg $O_3/mg$ DOC, the rate of BDOC formation became slow down, 4. from above 2mg $O_3/mg$ DOC, BDOC formation was quantitatively negligible, In conclusion, it needs further systematic study and research concerned to biodegradability and treatability by ozonation in terms of organic characteristics and experimental conditions because it was hard to find out the consistent experimental data comparable each other that were performed by numbers of research authors.

• Journal of environmental and Sanitary engineering
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• v.13 no.1
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• pp.166-173
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• 1998

This study was to investigate the effects of preozonation on the waterborne organic removal by the biologically active GAC fluidized bed on a laboratory scale. The raw water to be treated comes from midstream of Han river. As the ozone dose was increased in the range of $1~3{;\}mgO_{3}/mgDOC$, it produced BDOC from 1.82 to 2.65 times. And BDOC formation can be expressed as [BDOC] = 0.74 + 0.21[DOC] ($R^{2}{\;}={\;}0.8399$). The effects of combination of ozonation followed by BACFB (Biological Activated Carbon Fluidized Bed) process were analyzed. At the ozone doze of $1~3{\;}mgO_{3}/mgDOC$, the large fraction of BDOC was removed by BACFB, but parameter revealed only around 10% reduction.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.2
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• pp.205-213
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• 2007

We have studied NOM(natural organic matters) adsorption and biodegradation on 3 kinds of activated carbon and a anthracite. Coal based activated carbon showed the highest DOC(dissolved organic carbon) adsorption capability and roconut(samchully), wood (pica) in the order among the 3 kinds of activated carbon(F400). The biomass amount and activity also showed on coal, wood and coconut based activated carbon in the order. Over 15 minutes EBCT(empty bed contact time) needed to achieve 10 to 17% average removal efficiency and $18\sim24%$ maximum removal efficiency of NOM biodegradation in biofilter using anthracite. Hydrophobic and below 10,000 dalton NOM was much easier to adsorb into the activated carbon than hydrophilic NOM, THMFP(trihalomethane formation potential) and BDOC (biodegradable dissolved organic carbon)$_{slow}$ were much easier than HAA5FP(haloacetic acid 5 formation potential) and $BDOC_{rapid}$ to adsorb into the activated carbon. Hydrophilic and below 1,000 dalton NOM was much easily biodegraded and HAA5FP and $BDOC_{rapid}$ was easier than THMFT and $BDOC_{slow}$ to biodegrade in the biofilter.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.8
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• pp.533-540
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• 2012

The concentration of organic compounds was analyzed at each step of BAC (biological activated carbon) process though BDOC (biodegradable dissolved organic carbon) total/rapid/slow. Further, bacteria communities and biomass concentrations measured DGGE (denaturing gradirnt gel electrophoresis) and ATP (adenosine triphosphate) methods were analyzed. The bed volume of steady state is different based on assessment of organic compounds removal. Bed volumes at steady state in DOC, $BDOC_{rapid}$ and $BDOC_{total/slow}$ removal were around 27,500, 15,000 and 32,000, respectively. A biomass didn't change after the bed volume reached 22,500 according to analyzing HPC (heterotrophic plate count) and ATP concentration of bacteria. The concentration of HPC and ATP were $3.3{\times}10^8$ cells/g and $2.14{\mu}g/g$, respectively. The number of the DGGE band were only 5 at the bed volume 8,916, but increased up to 11 at the bed volume 49,632. As operation time increase, bacterial group were more diversity. Four bacteria species including Pseudomonas fluorescens, the uncultured bacterium similar to Acinetobacteria, uncultured Novosphingobium sp. and Flavobacterium frigidarium have detected from the early stages and Proteobacteria group were dominantly detected.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.2
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• pp.159-168
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• 2018

Climate change is believed to increase the amount of dissolved organic matter in surface water, as a result of the release of bulk organic matter, which make difficult to achieve a high quality of drinking water via conventional water treatment techniques. Therefore, the natural water treatment techniques, such as managed aquifer recharge (MAR), can be proposed as a alternative method to improve water quality greatly. Removal of bulk organic matter using managed aquifer recharge system is mainly achieved by biodegradation. Biodegradable dissolved organic carbon (BDOC) and assimilable organic carbon (AOC) can be used as water quality indicators for biological stability of drinking water. In this study, we compared the change of BDOC and AOC with respect to pretreatment methods (i.e., ozone or peroxone). The oxidative pretreatment can transform the recalcitrant organic matter into readily biodegradable one (i.e., BDOC and AOC). We also investigated the differences of organic matter characteristics between BDOC and AOC. We observed the decreases in dissolved organic carbon (DOC) and the tryptophan-like fluorescence intensities. Liquid chromatographic - organic carbon detection (LC-OCD) analysis also showed the reduction of the low molecular weight (LMW) fraction (15% removed, less than 500 Da), which is known to be easily biodegradable, and the biopolymers, high molecular weight fractions (66%). Therefore, BDOC consists of a broad range of organic matter characteristics with respect to molecular weight. In AOC, low molecular weight organic matter and biopolymers fraction was reduced by 11 and 6%, respectively. It confirmed that biodegradation by microorganisms as the main removal mechanism in AOC, while BDOC has biodegradation by microorganism as well as the sorption effects from the sand. $O_3$ and $O_3+H_2O_2$ were compared with respect to biological stability and dissolved organic matter characteristics. BDOC and AOC were determined to be about 1.9 times for $O_3$ and about 1.4 times for $O_3+H_2O_2$. It was confirmed that $O_3$ enhanced the biodegradability by increasing LMW dissolved organic matter.