• Journal of Microbiology and Biotechnology
• /
• 제24권7호
• /
• pp.879-887
• /
• 2014

Bacteria that mediate the anaerobic oxidation of ammonium (anammox) have been detected in natural ecosystems, as well as various wastewater treatment systems. In this study, sludge from a particular landfill leachate anaerobic treatment system was selected as the incubation seed for anammox microorganism enrichment owing to its possible anammox activity. Transmission electron microscopy observation, denaturing gradient gel electrophoresis analysis, and cloning/sequencing techniques were applied to identify the diversity of anammox microorganisms throughout the incubation. During the early stage of operation, the diversity of anammox microorganisms was similar to the original complex microbes in the seed sludge. However, as incubation time increased, the anammox microorganism diversity within the system that was originally dominated by Candidatus (Ca.) Brocadia sp. was replaced by Ca. Anammoxoglobus propionicus. The domination of Ca. Anammoxoglobus propionicus produced a stable removal of ammonia (70 mg-N/l) and nitrite (90 mg-N/l), and the total nitrogen removal efficiency was maintained at nearly 95%. The fluorescence in situ hybridization results showed that Ca. Anammoxoglobus propionicus was successfully enriched from $1.8{\pm}0.6%$ initially to $65{\pm}5%$ after 481 days of operation. Therefore, the present results demonstrated the feasibility of enriching Ca. Anammoxoglobus propionicus from leachate sludge, even though the original cell count was extremely low. Application of this seldom found anammox organism could offer an alternative to current ammonia-nitrogen treatment.

• 농업과학연구
• /
• 제48권3호
• /
• pp.589-596
• /
• 2021

Nitrogen applied to soil is highly prone to leaching and volatilization leading to gaseous emissions of nitrous oxide (N₂O) and ammonia (NH₃) which are of great environmental concern. Usage of biochar to reduce the discharge of nitrogen to the environment has attracted much interest in the recent past. Biochar is produced by pyrolyzing various biomasses under oxygen-limited conditions. Biochar is a carbonized material with high adsorptive powers for not only plant nutrients but also heavy metals. The objective of this study was to investigate the adsorption characteristics of NH₄-N onto biochar made from pine needles. The biochar was produced at various pyrolysis temperatures including 300, 400 and 500℃ and holding times of 30 and 120 minutes. The Langmuir isotherm was used to evaluate the adsorption test results. The chemical properties of the biochar varied with the pyrolysis conditions. In particular, the pH, EC and total carbon content increased with the increasing pyrolysis conditions. The rate of adsorption of NH₄-N by the biochar decreased with the increasing pyrolysis conditions. Of these conditions, biochar that was pyrolyzed at 300℃ for 30 minutes showed the highest adsorption rate of approximately 0.071 mg·g^-1. Thus, the use of biochar pyrolyzed at low temperatures with a short holding time can most efficiently reduce ammonia emissions from agricultural land.

• 한국어류학회지
• /
• 제22권3호
• /
• pp.147-153
• /
• 2010

대구 치어(평균 36.5 g)의 수온 (9, 11 그리고 $13^{\circ}C$)에 따른 절식 (fasting)과 식후(post-prandial) 총암모니아성 질소 (total ammonia nitrogen, TAN) 배설의 일간 패턴과 배설률을 조사하였다. 실험어는 10일 이상 실험 수온에서 순치한 후 각 실험 수온 조건의 암모니아 배설 측정 시스템으로 옮겨 TAN 배설률을 측정하였다. 절식 TAN 배설은 72시간 절식 후 측정하였고, 식후 TAN 배설은 상품 사료(단백질 함량 40.6%)를 하루에 두 번(08:00, 16:00h), 7일간 공급한 뒤 측정하였다. 실험어 사육수조 유입수와 배출수를 2시간 간격으로 24시간 동안 채수하여 TAN을 분석하였으며, 모든 실험 조건은 3반복으로 실시하였다. 절식 및 식후 TAN 배설 모두 수온 상승에 따라 증가하였다 (p<0.05). 절식 시 시간당 평균 TAN 배설률은 수온 9, 11 그리고 $13^{\circ}C$에서 각각 9.3, 11.0 그리고 $11.9mg\;TAN\;kg\;fish^{-1}\;h^{-1}$이었고, $11^{\circ}C$와 $13^{\circ}C$가 $9^{\circ}C$에 비해 유의적으로 높았다 (p<0.05). 식후 시간당 평균 TAN 배설률의 경우 수온 9, 11 그리고 $13^{\circ}C$에서 각각 23.0, 31.6 그리고 $45.4\;mg\;TAN\;kg\;fish^{-1}\;h^{-1}$으로 나타났다. 최대 평균 TAN 배설률은 최초 사료 공급 10시간 후 나타났으며, 수온 9, 11 그리고 $13^{\circ}C$에서 각각 38.0, 52.9 그리고 $77.5\;mg\;TAN\;kg\;fish^{-1}\;h^{-1}$이였다. 수온 9, 11 그리고 $13^{\circ}C$에서 섭취한 질소에 대한 TAN 배설 비율은 각각 43.9, 46.4 그리고 48.4%로 나타나 $11^{\circ}C$와 $13^{\circ}C$가 $9^{\circ}C$에 비해 유의적으로 높았다(p<0.05). 이상의 결과에서 수온은 대구 치어의 질소 대사에 유의한 영향을 미치는 것으로 나타났다.

• 한국습지학회지
• /
• 제20권4호
• /
• pp.417-423
• /
• 2018

축산 지역 하류에 위치한 농업용 저수지의 강우시 유입, 유출수 분석을 통해 축산지역의 강우 유출 특성과 저류지에 의한 축산계 비점 오염물질의 저류형 시설에 의한 유출 저감 효율을 분석하였다. 급경사지에 위치한 한우 축산 지역의 비점 오염물질 유출은 주로 초기세척현상에 의해 발생됨을 알 수 있었으며 강우시의 유입수 농도는 비강우시에 비해 SS농도가 가장 높게 발생하고 있으며 T-P도 4배 이상 증가하는 양상을 보인다. 반면 총질소는 평균 30% 증가하는 것으로 나타나는데 질소항목으로 보면 질산성 질소는 거의 변화가 없는 반면에 암모니아성 질소가 2배 이상 증가하고 있다. 저류형 비점 제거시설 효율 분석 결과 비강우시 총인 제거효율이 53%로 가장 높고 부유물질은 37% 제거되고 있다. 유기물질은 10% 내외, 총질소는 5% 이내로 제거되며 부영양화로 녹조가 번성하는 하절기에는 오히려 유출수의 질소농도가 더 높아지는 경우도 빈번히 발생하고 있다. 강우시의 유입수 농도는 비강우시에 비해 SS농도가 가장 높게 발생하고 있으며 T-P도 4배 이상 증가하는 양상을 보인다. 강우시 부유물질의 제거효율은 60%로 나타나고 있으며 총인은 22% 제거되어 비강우시에 비해 제거효율은 감소하고 있다. 환경부의 비점제거시설 기준보다 9배 이상의 용량을 지니고 있지만 비점 전용 시설로 활용되지 못하는 탓에 장마철에 거의 만수 상태로 담수하여 비점제거 효율에 있어서는 충분한 효과를 보이지 못하고 있는 것으로 나타나 저수지의 용량 뿐 아니라 수문관리 등 유지관리도 비점 제거효율에 영향을 미치는 중요 인자로 분석되었다.

• 한국물환경학회지
• /
• 제22권2호
• /
• pp.203-208
• /
• 2006

A continuous feed and cyclic draw SBR process was developed to overcome flow rate fluctuation and to maximize organic matters utilization efficiency for nitrogen and phosphorus removal. The developed SBR process was operated with two parallel reactors. Influent was supplied to one reactor which was not obligately aerated. At the same time, the other reactor was just aerated without supplying influent. In addition this mode was changed periodically. Cycle time was 6hr and aeration time ratio($t_{aer}/t_{total}$) was 0.33, respectively. $COD_{cr}$ and SS removal efficiencies of 95% or higher were achieved. Nitrogen removal was so greatly influenced by influent $COD_{cr}/T-N$ ratio. At influent $COD_{cr}/T-N$ ratio of 5.7, removal efficiencies of ammonia-N, T-N and T-P were 96%, 78% and 55%, respectively. Influent $COD_{cr}/T-N$ of 4 or higher ratio was necessary to achieve 60% or higher nitrogen removal. Organic matters of influent was efficiently utilized in denitrification reaction and consumed COD has a good correlation with removed T-N(about 6.5 mgCOD/mgTN). Continuous feed and cyclic draw SBR process could be one of alternative processes for the removal of nutrients in rural area where $COD_{cr}/T-N$ ratio was low and fluctuation of flow rate was severe.

• Asian-Australasian Journal of Animal Sciences
• /
• 제27권1호
• /
• pp.46-54
• /
• 2014

This study was conducted to investigate the effects of eucalyptus (E. Camaldulensis) crude oils (EuO) supplementation on voluntary feed intake and rumen fermentation characteristics in swamp buffaloes. Four rumen fistulated swamp buffaloes, body weight (BW) of $420{\pm}15.0$ kg, were randomly assigned according to a $2{\times}2$ factorial arrangement in a $4{\times}4$ Latin square design. The dietary treatments were untreated rice straw (RS) without EuO (T1) and with EuO (T2) supplementation, and 3% urea-treated rice straw (UTRS) without EuO (T3) and with EuO (T4) supplementation. The EuO was supplemented at 2 mL/h/d in respective treatment. Experimental animals were kept in individual pens and concentrate mixture was offered at 3 g/kg BW while roughage was fed ad libitum. Total dry matter and roughage intake, and apparent digestibilites of organic matter and neutral detergent fiber were improved (p<0.01) by UTRS. There was no effect of EuO supplementation on feed intake and nutrient digestibility. Ruminal pH and temperature were not (p>0.05) affected by either roughage sources or EuO supplementation. However, buffaloes fed UTRS had higher ruminal ammonia nitrogen and blood urea nitrogen as compared with RS. Total volatile fatty acid and butyrate proportion were similar among treatments, whereas acetate was decreased and propionate molar proportion was increased by EuO supplementation. Feeding UTRS resulted in lower acetate and higher propionate concentration compared to RS. Moreover, supplementation of EuO reduced methane production especially in UTRS treatment. Protozoa populations were reduced by EuO supplementation while fungi zoospores remained the same. Total, amylolytic and cellulolytic bacterial populations were increased (p<0.01) by UTRS; However, EuO supplementation did not affect viable bacteria. Nitrogen intake and in feces were found higher in buffaloes fed UTRS. A positive nitrogen balance (absorption and retention) was in buffaloes fed UTRS. Supplementation of EuO did not affect nitrogen utilization. Both allantoin excretion and absorption and microbial nitrogen supply were increased by UTRS whereas efficiency of microbial protein synthesis was similar in all treatments. Findings of present study suggested that EuO could be used as a feed additive to modify the rumen fermentation in reducing methane production both in RS and UTRS. Feeding UTRS could improve feed intake and efficiency of rumen fermentation in swamp buffaloes. However, more research is warranted to determine the effect of EuO supplementation in production animals.

• Asian-Australasian Journal of Animal Sciences
• /
• 제24권12호
• /
• pp.1718-1728
• /
• 2011

Two experiments were conducted to investigate the in vitro ability of keratinase to hydrolyze soybean glycinin and ${\beta}$-conglycinin and to evaluate the in vivo effects of keratinase when included in corn-soybean diets with different levels of crude protein and fed to nursery pigs. In experiment 1, a saturated keratinase solution (1 ml) was added to two blank controls of either glycinin or ${\beta}$-conglycinin resulting in the hydrolysis of 94.74% glycinin and 88.89% ${\beta}$-conglycinin. In experiment 2, 190 pigs (8.3${\pm}$0.63 kg BW) were allotted to one of four treatments in a 2${\times}$2 factorial arrangement on the basis of body weight, and sex was balanced among the pens. The effects of crude protein (19 vs. 22%) and keratinase (0 vs. 0.05%) were studied. Each treatment was applied to six pens with seven (two pens) or eight pigs per pen. Pigs were fed the experimental diets for 21 d. Weight gain and feed conversion ratio were improved (p<0.05) with keratinase supplementation while feed intake was reduced (p<0.05). Keratinase supplementation increased (p<0.05) the apparent total tract digestibility of dry matter, energy, crude protein and phosphorus. Keratinase supplementation also increased n-butyric acid in the cecum and colon, lactobacilli and total anaerobe counts in the colon as well as the ratio of villus height to crypt depth in the ileum. Additionally, fecal score, ammonia nitrogen and branch chain volatile fatty acids in the colon, E. coli and total aerobe counts in the colon, crypt depth in the jejunum and ileum as well as serum interleukin-1 and interleukin-6 concentrations were also decreased (p<0.05) by keratinase supplementation. A reduction in dietary crude protein decreased (p<0.05) colon ammonia nitrogen concentration and cecal propionic acid and branch chain volatile fatty acid concentrations. In addition, cecal E. coli counts, colon total anaerobe counts, ileal crypt depth, and serum interleukin-1 and interleukin-6 concentrations were also decreased (p<0.05) with the reduction of dietary crude protein. With the exception of fecal scores, there were no significant interactions between crude protein and keratinase. This study provides evidence that dietary keratinase supplementation improved nursery pig performance by improving intestinal morphology and ecology, thus improving nutrient digestibility and alleviating the inflammatory response.

• 한국수산과학회지
• /
• 제35권1호
• /
• pp.21-26
• /
• 2002

Package 형태로 설계하고 제작된 pilot scale 순환여과식 양식시스템에 틸라피아를 $2\%$의 사육밀도로 수용하여 사육조의 각종 수질인자의 변화를 측정하고 회전원판 반응기, floating bead filter, 포말분리기 등의 순환수 처리효율을 검토하여 순환여과식 양식시스템의 개시운전시 발생하는 현상을 고찰하고 순환수 처리장치의 안정화에 소요되는 시간을 측정하고자 하였다. 평균 어체중 392.8g의 나일 틸라피아 173마리를 수용하여 일간 보충수를 사육조 용적의 $10\%$를 사용하여 14일간 어류사육을 실시하여 생물학적 순환수 처리장치인 회전 원판 반응기의 효율 변화를 검토하였다. 암모니아성 질소는 사료 투입 직후부터 증가하여 7일 후 부터는 $0.3gm^3$ 정도의 농도를 보였다. 사료 투입 후 3일이 경과하면서부터 아질산성 질소, 7일 이후부터 질산성 질소가 증가하였으며 12일이 경과하면서 시스템의 아질산성 질소의 농도가 감소하여 회전원판 반응기가 숙성되었다 총 무기질소는 사료 투입 후 10일이 경과하면서 $30g/m^3$ 정도의 일정한 농도를 유지하였다. 사육조 내의 용존 산소농도는 $4{\~}5g/m^3$의 안정된 농도를 유지하였으며 pH와 총알칼리도는 질산화 반응기의 숙성에 따라 어류생장에 영향을 미치지 않는 범위에서 감소하였다 총 부유 고형물과 화학적 산소 요구량은 보충수와 거의 동일한 수질을 유지할 수 있었다. 회전원판 반응기는 암모니아 제거와 동시에 용존산소 폭기 효율도 나타내었고 floating bead filter는 고형물 제거뿐 아니라 질산화에도 뛰어난 효율을 보였으며 회전 원판 반응기는 사료 투입 후 2일, floating bead filter는 4일째부터 암모니아 제거가 시작되었다.

• 센서학회지
• /
• 제29권2호
• /
• pp.93-99
• /
• 2020

A colorimetric paper sensor was used to detect volatile nitrogen-containing compounds emitted from spoiled salmon filets to determine their freshness. The sensing mechanism was based on acid-base reactions between acidic pH-indicating dyes and basic volatile ammonia and amines. A sensing layer was simply fabricated by drop-casting a dye solution of bromocresol green (BCG) on a polyvinylidene fluoride substrate, and its color-change response was enhanced by optimizing the amounts of additive chemicals, such as polyethylene glycol, p-toluene sulfonic acid, and graphene oxide in the dye solution. To avoid the adverse effects of water vapor, both faces of the sensing layer were enclosed by using a polyethylene terephthalate film and a gas-permeable microporous polytetrafluoroethylene sheet, respectively. When exposed to basic gas analytes, the paper-like sensor distinctly exhibited a color change from initially yellow, then to green, and finally to blue due to the deprotonation of BCG via the Brønsted acid-base reaction. The use of ammonia analyte as a test gas confirmed that the sensing performance of the optimized sensor was reversible and excellent (detection time of < 15 min, sensitive naked-eye detection at 0.25 ppm, good selectivity to common volatile organic gases, and good stability against thermal stress). Finally, the coloration intensity of the sensor was quantified as a function of the storage time of the salmon filet at 28℃ to evaluate its usefulness in monitoring of the food freshness with the measurement of the total viable count (TVC) of microorganisms in the food. The TVC value increased from 3.2 × 10⁵ to 3.1 × 10⁹ cfu/g in 28 h and then became stable, whereas the sensor response abruptly changed in the first 8 h and slightly increased thereafter. This result suggests that the colorimetric response could be used as an indicator for evaluating the degree of decay of salmon induced by microorganisms.

• 상하수도학회지
• /
• 제13권2호
• /
• pp.55-65
• /
• 1999

AF(anaerobic filter)/BAF(biological aerated filter) system and UASB(upflow anaerobic sludge blanket)/BAF system, of which system effluents were recirculated to the anaerobic reactors in each system, were operated in order to investigate the performance in simultaneous removal of organics and nitrogen in high-strength dairy wastewater. Advanced anaerobic treatment processes of AF and UASB were evaluated on applicability as pre-denitrification reactors, and BAF was also evaluated on the performance in oxidizing the remaining organics and ammonia nitrogen. At system HRTs of 4.0 to 4.5 days and recirculation ratios of one to three, the AF/BAF system could achieve more than 99% of organics removals and 64 to 78% of total nitrogen removals depending upon the recirculation ratio. Although the UASB/BAF system also showed more than 99% of organics removals, total nitrogen removals in the UASB/BAF system were 53 to 66% which are lower than those in the AF/BAF system at the corresponding recirculation ratios. Optimum recirculation ratios considering simultaneous removal of organics and nitrogen and cost-effectiveness, were in the range of two to three. The upflow AF packed with crossflow module media, as a primary treatment of the anaerobic reactor/BAF system, showed better performances in denitrification, SS removals, and gas production than the UASB. Higher loading rate of suspended solids from the UASB increased the backwashing times in the following BAF. Especially, at a recirculation ratio of three in the UASB/BAF system, the increase in head loss due to clogging in the BAF caused frequent backwashing, at least once d day. The BAF showed the high nitrification efficiency of average 99.2% and organics removals more than 90% at organics loading rate less than $1.4KgCOD/m^3/d$ and $COD/NH_3-N$ ratio less than 6.4. It was proved that the simplified anaerobic reactor/BAF system could maximize the organics removal and achieve high nitrogen removal efficiencies through recirculation of system effluents to the anaerobic reactor. The AF/BAF system can, especially, be a cost effective and competitive alternative for the simultaneous removal of organics ana nitrogen from wastewaters.