• 한국지하수토양환경학회지:지하수토양환경
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• 제27권6호
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• pp.37-46
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• 2022

As the amount of livestock wastewater increases, ammonia contamination in surface water and groundwater is also increasing, and its treatment is urgently needed. In this study, indigenous soil bacteria was utilized for ammonia removal in artificial wastewater and associated removal mechanisms and efficiencies were evaluated. Two batch reactors were configurated to contain natural soil and artificial wastewater at 1:10 mass ratio, and incubated for 84 and 168 hours, respectively. The results showed that ammonia was completely removed within 48 and 72 hours in the first and second reactors, respectively. There were no significant changes in ammonia concentrations in the control groups without soil. Nitrate was formed in the reactors, indicating that the main removal mechanism of ammonia was nitrification by nitrifying bacteria. Nitrate was further converted to nitrogen gas by denitrification in the anaerobic environment, which was caused by consumption of oxygen during the nitrification process.

• 한국물환경학회지
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• 제29권1호
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• pp.1-6
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• 2013

This study was focused on improving nitrification efficiencies of M-dephanox (Modified-Dephanox) process. Rotating biological contactor (RBC) was used instead of floating sponge type media in nitrification reactor. High ammonia removal efficiencies were observed in nitrification reactor, regardless of organic loading from contactor of M-dephanox process. Denitrification efficiencies were also increased to maintain low $NO_3-N$ concentration in effluent. This enhanced phosphate release in anaerobic contactor and resulted in high removal efficiencies of phophorus. Average removal efficiencies of $TCOD_{Cr}$ and $SCOD_{Cr}$ were 93.8% and 81.6%, respectively, while those of TKN and ${NH_4}^+-N$ were 80.9% and 74.4%, respectively. As for phosphorous treatment, the average removal efficiencies of TP and OP were 94.7% and 94.3%, respectively. Also, effect of operating temperature on nitrogen removal was examined. Average removal efficiency of TN was 65.8 % at $15^{\circ}C$ or below (at average temperature of $13.3^{\circ}C$), while that was 82.8% at $15^{\circ}C$ or above (at average temperature of $21.9^{\circ}C$).

• KSBB Journal
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• 제22권4호
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• pp.191-196
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• 2007

본 연구는 급속한 산업 발전으로 인해 일어난 많은 수질오염 문제 중 생활하수의 처리방법에 관심을 기울여 생물막 공법을 이용하였는데, 이는 소규모 오폐수 처리장치에서 운전과 유지가 간단하고 활성슬러지 공정보다 넓은 부지를 필요로 하지 않기 때문이다. 생물막 공법 중 생물여상법의 변법을 적용한 Pilot 규모의 상향류식 충전탑형 반응기로 내부의 담체로는 폐토기와 폐비닐을 넣어 혐기조와 호기조를 구성하였고, 생활 오수로는 식당 오수를 이용하여 Lab.-Scale 실험 후 Pilot-Scale로 Scale-up하여 100여일 간에 걸쳐 실험을 수행하였다. 실험은 연속 포기시 일정 HRT에서 유기물과 질소, 인 제거율을 살펴보았다. 실험결과 $BOD_5$와 SS의 평균 제거율은 각각 94.33%와 87.77%로 높은 제거율을 보였으나, $COD_{Cr}$은 81.46%로 목표 제거율 90% 이상에 미치지 못하였고, T-N과 T-P도 각각 71.92%와 21.10%로 예상보다 약간 낮았다. 특히 $COD_{Cr}$와 T-N의 제거율은 지난 Lab.-Scale 때보다 약 10% 정도의 감소를 하여 Pilot-scale에 내외적인 문제가 작용한 것으로 보였다.

• 한국수소및신에너지학회논문집
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• 제17권4호
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• pp.379-388
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• 2006

Two mesophilic trickling bed bioreactors filled with two different types of media, hydrophilic- and hydrophobic-cubes, were designed and conducted for hydrogen production under the anaerobic fermentation of sucrose. Each bioreactor consisted of the column packed with polymeric cubes and inoculated with heat-treated sludge obtained from anaerobic digestion tank. A defined medium containing sucrose was fed by the different hydraulic retention time(HRT), and recycle rate. Hydrogen concentrations in gas-phase were constant, averaging 40% of biogas throughout the operation. Hydrogen production rate was increased till $10.5\;L{\cdot}h^{-1}{\cdot}L^{-1}$ of bioreactor when influent sucrose concentrations and recycle rates were varied. At the same time, the hydrogen production rate with hydrophobic media application was higher than its hydrophilic media application. No methane was detected when the reactor was under a normal operation. The major fermentation by-products in the liquid effluent of the both trickling biofilters were acetate, butyrate and lactate. In order to run in the long term operation of both reactor filled with hydrophilic and hydrophobic media, biofilm accumulation on hydrophilic media and biogas produced should be controlled through some process such as periodical backwashing or gas-purging. Four sample were collected from each reactor on the opposite hydrogen production rate, and their bacterial communities were compared by terminal restriction fragment length polymorphism (T-RFLP) analysis of PCR products generated using bacterial 16s rRNA gene primers (8f and 926r). It was expressed a marked difference in bacterial communities of both reactors. The trickling bed bioreactor with hydrophobic media demonstrates the feasibility of the process to produce hydrogen gas. A likely application of this reactor technology can be hydrogen gas recovery from pre-treatment of high carbohydrate-containing wastewaters.

• 유기물자원화
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• 제10권1호
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• pp.87-95
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• 2002

슬러지의 용해율 증가 및 생분해율 향상을 위해 전처리 방법별 처리조건 및 회분, 연속실험을 실시하였다. 용해효과실험에서 SCOD 기준 용해율 효과는 온도무고정 초음파처리(35분)가 가장 높고, 다음으로 알칼리처리(pH13), 열처리($200^{\circ}C$, 30min), 온도고정 초음파처리(60분)순서였다. 초기 회분실험에서 적정 혼합비율은 가스생성량을 기준하여 종오니 : 기질비가 4 : 6일 때(유기물 부하량$3.48kg/m^3{\cdot}day$) 가장 효과적이었다. 회분실험에서 가스발생량은 열처리($200^{\circ}C$, 30min)가 가장 높고, 다음으로 초음파처리(온도 무조정), 알칼리처리(pH9), 초음파처리(온도조정)순서였다. 연속실험은 회분실험에서 가장 효과적인 열처리($200^{\circ}C$, 30min) 시료를 이용하였다. pH는 열처리 (pH 7.2~7.3)가 무처리 (pH 6.9~7.0)시료에 비해 다소 높은 값을 나타내었다. HRT가 길수록 유출수의 pH가 상승하는 경향을 나타내고 있고, 이는 유기물부하의 감소에 따른 생성유기산의 농도저하와 유기산의 가스로의 전환에 의해 생성된 $N_2$가스의 완충작용에 기인한다고 생각된다. 반응조내의 SCOD 농도는 전처리 시료가 무처리에 비해 약 2.5배 높고, 또 HRT는 짧을수록 높았다. 용해성 단백질 및 탄수화물 농도도 전처리 시료가 무처리 시료에 비해 각각 2배 및 3.3배 높았다. 가스 생성량은 열처리시료가 무처리 시료에 비해 약 2배 높아, 열처리가 소화효율 향상에 효과적임을 알 수 있었다. 가스 생성량은 HRT 7day일 때 가장 유리했다. 그러나 HRT 2.5day 일 때 가스 생성량은 무처리 시료에 비해서도 낮은 값을 나타내어 혐기성 세균이 고농도로 축적된 유기산의 저해를 받았기 때문이라고 생각된다.

• Journal of Microbiology and Biotechnology
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• 제17권2호
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• pp.253-261
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• 2007

Molecular and cultivation techniques were used to characterize the bacterial communities of biobead reactor biofilms in a sewage treatment plant to which an Aerated Up-Flow Biobead process was applied. With this biobead process, the monthly average values of various chemical parameters in the effluent were generally kept under the regulation limits of the effluent quality of the sewage treatment plant during the operation period. Most probable number (MPN) analysis revealed that the population of denitrifying bacteria was abundant in the biobead #1 reactor, denitrifying and nitrifying bacteria coexisted in the biobead #2 reactor, and nitrifying bacteria prevailed over denitrifying bacteria in the biobead #3 reactor. The results of the MPN test suggested that the biobead #2 reactor was a transition zone leading to acclimated nitrifying biofilms in the biobead #3 reactor. Phylogenetic analysis of 16S rDNA sequences cloned from biofilms showed that the biobead #1 reactor, which received a high organic loading rate, had much diverse microorganisms, whereas the biobead #2 and #3 reactors were dominated by the members of Proteobacteria. DGGE analysis with the ammonia monooxygenase (amoA) gene supported the observation from the MPN test that the biofilms of September were fully developed and specialized for nitrification in the biobead reactor #3. All of the DNA sequences of the amoA DGGE bands were very similar to the sequence of the amoA gene of Nitrosomonas species, the presence of which is typical in the biological aerated filters. The results of this study showed that organic and inorganic nutrients were efficiently removed by both denitrifying microbial populations in the anaerobic tank and heterotrophic and nitrifying bacterial biofilms well-formed in the three functional biobead reactors in the Aerated Up-Flow Biobead process.

• 한국환경과학회지
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• 제21권12호
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• pp.1495-1501
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• 2012

In this study, an experiment was conducted on influent water with low concentrations of organic matter, such as river water or secondary treatment water of a sewage treatment plant, according to HRT changes by using aerobic biofilm. In the biofilm process, as the biofilm increases in thickness, the inner membrane can be low in oxygen transfer rate and become anaerobic conditions, while the detachment of biomass from biofilm occurs. To overcome these limitations in the detachment of microorganisms in biofilm, the yarn, which was made from poly propylene(PP), was weaved and manufactured into a tube. Then, a test was carried out by injecting air so that the interior of the biofilm could create aerobic conditions. The results of the experiment showed that the removal efficiency of $TCOD_{cr}$ reached 66.1~81.2% by HRT 2hr, and 50.9 ~61.8% after HRT 1 hr. The removal efficiency of $SCOD_{cr}$ was 45.9 to 55.1% by HRT 1hr, and 26.1% in HRT 0.5hr, showing the highest removal efficiency in HRT 1hr. The SS removal efficiency was at 81.8 to 94.6%, and the effluent SS concentration was very low, indicating less than 2.2 mg/L in all HRT's. As a result, the $SCOD_{cr}$ and $NH_4{^+}$-N that were removed per specific surface area and attached to microbial biofilm showed the highest efficiency in HRT 1hr with 8.37 $gSCOD_{cr}/m^2{\cdot}d$, 2.93 $gNH_4{^+}-N/m^2{\cdot}d$. From the result of reviewing the characteristics of biofilm growth, microorganisms were found to be attached, and increased by 36 days. Later, they decreased in number through detachment, but showed a tendency to increase again 41 days later due to microbial reproduction.

• Asian-Australasian Journal of Animal Sciences
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• 제28권6호
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• pp.816-826
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• 2015

The present experiment evaluated the influence of moisture level and anaerobic fermentation on aerobic stability of total mixed ration (TMR). The dynamic changes in chemical composition and microbial population that occur after air exposure were examined, and the species of yeast associated with the deterioration process were also identified in both non-fermented and fermented TMR to deepen the understanding of aerobic deterioration. The moisture levels of TMR in this experiment were adjusted to 400 g/kg (low moisture level, LML), 450 g/kg (medium moisture level, MML), and 500 g/kg (high moisture level, HML), and both non-fermented and 56-d-fermented TMR were subjected to air exposure to determine aerobic stability. Aerobic deterioration resulted in high losses of nutritional components and largely reduced dry matter digestibility. Non-fermented TMR deteriorated during 48 h of air exposure and the HML treatment was more aerobically unstable. On dry matter (DM) basis, yeast populations significantly increased from $10^7$ to $10^{10}cfu/g$ during air exposure, and Candida ethanolica was the predominant species during deterioration in non-fermented TMR. Fermented TMR exhibited considerable resistance to aerobic deterioration. Spoilage was only observed in the HML treatment and its yeast population increased dramatically to $10^9cfu/g$ DM when air exposure progressed to 30 d. Zygosaccharomyces bailii was the sole yeast species isolated when spoilage occurred. These results confirmed that non-fermented and fermented TMR with a HML are more prone to spoilage, and fermented TMR has considerable resistance to aerobic deterioration. Yeasts can trigger aerobic deterioration in both non-fermented and fermented TMR. C. ethanolica may be involved in the spoilage of non-fermented TMR and the vigorous growth of Z. bailii can initiate aerobic deterioration in fermented TMR.

• 대한환경공학회지
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• 제31권2호
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• pp.139-146
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• 2009

본 연구에서는 두부공장에서 발생된 폐수를 이용한 생물학적 수소생성 특성과 미생물의 군집 변화를 살펴보았다. 두부 폐수는 산 또는 알카리 조건에서 전처리 된 후 수소생성량을 비교 하였으며, 산처리와 열처리를 병행하여 전처리 하였을 때 가장 왕성한 수소생산을 보였으며, Gompartz 방정식을 이용한 수소가스 발생량($P_h$)은 약 661.01 mL이고 최대 수소 생성율($R_h$)은 12.21 mL/g dry wt biomass/hr 이였다. 16S rDNA의 PCR-DGGE 결과 대부분 군집은 Streptococcus sp. 미생물로 규명되었으며 수소생성에 기여도가 큰 미생물은 Streptococcus gallolyticus sub sp.으로 판단되었다.

• 대한환경공학회지
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• 제35권8호
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• pp.564-570
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• 2013

산성광산배수처리를 위한 국내 대부분의 처리시설은 자연정화법을 사용하고 있으며 이들 중 일부 처리장에서는 고농도의 망간이 유출되고 있는데 이는 망간산화를 위해 높은 pH (>9)가 요구되기 때문이다. 본 연구는 망간처리 공정 중 경제성을 높일 수 있는 생물학적 망간처리의 가능성을 타진하는데 그 목적이 있으며 망간산화미생물은 Pseudomonas sp. MN5를 이용하였다. 회분식 실험을 통해 수질조건에 따른 영향을 분석한 결과 pH 7에서 최고산화속도는 $10.4mg/L{\cdot}h$로 나타났다. 망간산화미생물을 담지한 연속류 실험결과 운전 초기 망간 농도는 42 mg/L에서 6 mg/L 이하로 크게 감소하였지만 망간산화미생물의 산소소비에 의한 혐기조건 형성으로 망간의 재용출 현상이 나타났다.