• Animal Bioscience
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• 제35권9호
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• pp.1390-1399
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• 2022

Objective: The objective of this study was to evaluate the effects of dietary supplementation of Schizosaccharomyces pombe (S. pombe) -expressed phytase on growth performance, apparent ileal digestibility, organ indexes, meat quality, toe ash, and footpad lesions score in broiler chicks. Methods: A total of 390 one-day-old broiler chicks were randomly assigned to 5 groups based on the initial body weight (42.15±0.17 g), there were 6 replicate cages per treatment and 13 birds (mixed sex) per cage. The experimental period was 45 days, including 4 periods (starter, days 1 to 10; grower, days 11 to 24; finisher 1, days 25 to 38; finisher 2, days 39 to 45). Dietary treatments were based on a corn-soybean meal-basal diet and supplemented with 500, 750, 1,000, and 1,500 FTU/kg S. pombe-expressed phytase. One phytase unit (FTU) was defined as the amount of enzyme that catalyzes the release of one micromole phosphate from phytate per minute at 37℃ and pH 5.5. Results: The inclusion of increasing levels of phytase in the diet linearly increased the body weight gain during days 1 to 10 (p = 0.001), 25 to 38 (p = 0.016), 39 to 45 (p = 0.018), and 1 to 45 (p = 0.004), feed intake during days 25 to 38 (p = 0.032), feed conversion ratio during days 1 to 10 (p = 0.001), 39 to 45 (p = 0.038), and 1 to 45 (p = 0.012), carcass weight (p = 0.035), toe ash (p<0.001), and apparent ileal phosphorus digestibility (p = 0.049). However, the footpad lesions score (p = 0.040) decreased linearly with the increase in phytase levels in the diet. Conclusion: Dietary supplementation of S. pombe-expressed phytase was beneficial to the growth performance, toe ash, apparent ileal phosphorus digestibility, and footpad lesions of broiler chicks in a dose-dependent manner.

• 한국환경농학회지
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• 제32권1호
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• pp.9-16
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• 2013

주암호내 복내 저수구역에서 서식하는 자생식물체들이 침수시 주암호 수질에 미치는 영향을 파악하기 위하여 복내 저수구역이 침수되기 전인 2010년 8월의 영양염류(질소 및 인) 최대 흡수량과 침수 후 다시 침수이전 수위로 회복된 2011년 2월에 남은 식생의 영양염류 잔존량 차이를 이용하여 산술적인 영양염류 용출량을 산정하였다. 2010년 8월에 침수되기전 복내 저수구역내 식생의 면적은 987,872 $m^2$이었다. 침수전인 2010년 8월에 복내 저수구역내 식생의 분포면적별 T-N의 흡수량은 물억새가 247 kg/total reservoir area, 이삭사초가 11,340 kg/total reservoir area로 분포면적이 넓은 이삭사초의 T-N 흡수량이 물억새에 비해 많았으며, T-P의 흡수량도 1,231 kg/total reservoir area로 이삭사초가 가장 많았다. 침수 후 2011년 2월에 조사된 상부지역 물억새의 T-N 및 T-P의 잔존량은 각각 34 및 11 kg/total reservoir area로 침수 전에 비해 감소하였고, 이삭사초의 T-N 및 T-P의 잔존량은 각각 491 및 68 kg/total reservoir area로 물억새와 비슷한 경향으로 침수 전에 비해 감소하였다. 이상의 결과를 종합하여 복내 저수구역내 식생의 T-N 및 T-P의 총 용출량을 산정한 결과 T-N 용출량은 복내 저수구역 총 식생면적(987,872 $m^2$)당 12,212 kg, T-P 용출량은 총 식생면적당 1,324 kg이었다. 따라서 복내 저수구역내 자생식물은 침수시 수중에서 분해되면서 식물체내 질소 및 인이 용출되어 주암호의 수질오염을 가중시킬 수 있는 한 요인이 될 수 있으므로 호소내 수질개선을 위해서는 저수구역내 식물체의 관리방안이 필요할 것으로 판단된다.

• 한국환경과학회지
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• 제20권7호
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• pp.845-855
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• 2011

The aim of this paper is to correlate the release characteristics of marine and lake sediment with their vicinal oxic conditions. We performed lab-scale simulation experiments using field sediment and water in order to compare the release concentrations and the release rates one another. To provide a few different kinds of oxic environments we used natural air flow and some oxygen releasing compounds such as $CaO_2$ and $MgO_2$. In case of phosphates, in each oxic condition, removal of phosphorus via biological activity and that via salt precipitation with the metal ions lowered the release rates. The behavior of the nitrogen-origin salts seemed to greatly depend on the typical biological actions - growth of biomass, nitrification, and partial denitrification. Generally speaking, the control of releases of $NH_3$-N, $PO_4$-P, T-N and T-P was successful under the oxic conditions meanwhile COD, nitrates and nitrites were difficult to reduce the releases into the bulk water because of the considerable microbial oxidation. Based on typical diffusive mass transfer kinetics the changes of concentrations of the nutrients were computed for qualitative and quantitative comparisons.

• 한국물환경학회지
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• 제20권1호
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• pp.42-47
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• 2004

This study was accomplished to develope an advanced wastewater treatment process using high MLSS in anoxic tank aimed to improve nutrient removal and to reduce wasting sludge. It was operated with 4 Modes with varing solid concentration and internal recycle ratios. Mode I, II, III was operated 1.0~1.5% MLSS concentration at anoxic tank with 50% sludge recycle rate, however, each internal recycle rate were 100%, 200%, 300% and Mode IV was operated 1.5~2.0% MLSS concentration at anoxic tank with 50% sludge recycle rate and 100% internal recycle rate. The COD removal efficiency didn't show any big difference from Mode I to IV. The average COD removal rate was over than 90%. The T-N removal rate was 73%, the highest rate in all mode. The 36% of SCOD is used for the denitrification and phosphorus release in the anoxic tank. Specific denitrification rate was 3.5mg $NO_3{^-}-N/g$ Mv/hr and denitrification time was 0.7hr. As MLSS concentration is higher in anoxic tank as denitrification time would be shorter. The T-P removal rate was average 70%. The phosphorus release accomplished from the anoxic tank because the anaerobic condition was prevalent in the anoxic due to the prompt completion of denitrification. Sludge production was 0.28 kgVSS/kg $BOD_{removed}$ under the 1.5% MLSS and 17 day SRT. It is prominent result which has 40% sludge reduce comparing with traditional activate sludge system.

• 한국환경과학회지
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• 제14권9호
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• pp.861-871
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• 2005

This study was carried out to get more operational characteristics of Anoxic(anaerobic)-Oxic-Anoxic-Oxic $(AO)_2$ sequencing batch biofilm reactors (SBBRs) at the low TOC concentration, The operating time in anoxic (anaerobic) time to oxic time was I : I. Experiments were conducted to find the effects of the aeration time distribution on the organic matters and nutrients removal. Three lab-scale reactors were fed with synthetic wastewater based on glucose as carbon source. During studies, the operation mode was fixed. The first aeration time to the second aeration time in SBBR-I was 2 : 3, and those in SBBR-2 and SBBR-3 were I : 4 and 3 : 2, respectively. The organic removal efficiency didn't show large difference among three reactors of different aeration time distribution. However, from these study results, the optimum aeration time distribution in the first and the second aeration time for biological nutrient removal was shown as 3 : 2. The release of phosphorus was inhibited at the second non-aeration period because of the low TOC concentration and the nitrate produced by the nitrification at the first aeration period.

• 한국환경보건학회지
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• 제40권4호
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• pp.322-329
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• 2014

Objectives: The purpose of this study was to investigate the effect of BIO-CLOD on advanced wastewater treatment for enhanced removal efficiency and meeting the stringent discharge water requirements of wastewater treatment plants. Methods: Two experimental apparatuses consisting of anaerobic, anoxic and aeration tanks were operated. One included a BIO-CLOD cultivation tank. Organic and nutrient parameters and removal efficiency were analyzed by pH, BOD, CODcr, SS, T-N and T-P. Results: The average removal efficiencies of BOD, COD and SS from the apparatus with BIO-CLOD tank installation were 95.5%, 88.6% and 92.9%, respectively, and these were higher than the results from the apparatus without BIO-CLOD. The average TP removal efficiency with BIO-CLOD tank marked 56.0%, higher than the 47.3% from the apparatus without one. BIO-CLOD showed a higher performance for TN removal at 49.6%, compared to the result without BIO-CLOD of 34.3% Conclusion: By reaction with BIO-CLOD, ammonia removal was effective in the aeration tank, as was phosphorus release in the anaerobic tank. Phosphorus luxury uptake and nitrification in aeration tank proceeded smoothly. The application of BIO-CLOD can improve the decrease of odor and settleability of activated sludge in a wastewater treatment plant, as well as increase the removal efficiency of organic and nutrient materials in water.

• BMB Reports
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• 제36권6호
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• pp.597-602
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• 2003

Acid phosphatases (APases) play a role in the release of phosphate in organic complexes in soil. We investigated tissue- and isoform-specific responses of APases to phosphorus (P) deficiency in three rice genotypes; Dasan-byeo, Sobi-byeo, and Palawan. The levels of shoot APase activity per protein were similar in the three genotypes. They significantly decreased with P deprivation that was longer than seven days. Root APase activity per protein was two- to three-fold higher in Dasan than in Sobi and Palawan. In all genotypes the APase activity increased in P-deficient plants, but the increase was higher in Sobi and Palawan. After 21 days of P deprivation, secreted APase activity increased more than eight-fold in Dasan and two-fold in Sobi and Palawan. Isoform profiles of shoot and root APases were most diverse in Dasan. The activities of the major isoforms in P-deficient shoots decreased in all three genotypes. Depending on the genotypes, further increases in constitutive isoforms and new induction of one to four isoforms occurred in P-deficient roots. The results indicate that tissue and genotype differences in the response of APase to P deficiency are primarily facilitated by the different responses of the isoforms.

• 물과 미래
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• 제22권1호
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• pp.117-125
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• 1989

본 연구는 활성슬러지공법을 변형시킨 무산소일염기일호기반응조를 사용해서 질산화일탈질소반응 및 인의 방출인초과축적반응을 유도하여 합성페수의 유기물, 질소 및 인을 동시에 제거하였다. 무질소조, 무염기 및 호기호 각각에 대한 반응특성을 조사하기 위해 실험실규모의 반응조가 운영되었으며 MLSS농도를 5000, 4200, 3300, 2600, 1900mg/l로, 변화시켜 COD제거율에 대한 생물학적 동력학계수를 결정하였다. 연구결과, 유기물 및 영양염이 변형된 슬러지공법에 의해 동시에 제거될 수 있음을 알았고, ortho-p 제거효율은 66%∼99%로 높게 나타났다.

• 한국수산과학회지
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• 제35권4호
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• pp.348-355
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• 2002

To know characteristics of water quality in Saemankeum area, we were investigated the water quality of surface layer from July of 1999 to June of 2000. The concentrations of COD and chlorophyll a were in the range of $0.64\~6.40$ (mean 1.96)mg/L, $1.95\~51.55$ (mean 11,07)$mg/m^3$, respectively. The annual mean concentrations of DIN, DIP were found to be 21.182 $\mu$g-at/L and 0,655 $\mu$g-at/L respectively, which were exceeding second grade of seawater quality standard. The nitrogen ratio to the phosphorus was lower than 1. Therefore, nitrogen was playing an important role in phytoplankton growth as limiting factor in study area. Mean values of eutrophication index were exceeding 1, which was the eutrophication criteria. Especially Mankyung and Dongjin estuary were shown over 10 as eutrophication index. Therefore, Saemankeum area could be evaluated to possibility area for eutrophication. Released rate for ammonia nitrogen and phosphate phosphorus from sediments were 62.92 ${\mu}g-at/m^3/hr$ and 6.71 ${\mu}g-at/m^3/hr$, respectively.

• Advances in environmental research
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• 제5권4호
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• pp.251-262
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• 2016

The biodegradability and decomposition efficiencies increase with the pre-treatment of sludge in a digestion process. In this study, the feasibility of ultrasound coupled with potassium permanganate oxidation as a disintegration method and digestibility of aerobic reactor fed with disintegrated sludge with ultrasound coupled potassium permanganate were investigated. The first stage of the study focused on determining the optimum condition for ultrasonic pre-treatment for achieving better destruction efficiency of sludge. The second part of the study, the aerobic digestibility of sludge disintegrated with ultrasound and potassium permanganate oxidation alone and combined were examined comparatively. The results showed that when 20 min of ultrasonic pre-treatment applied, the specific energy output was 49384 kJ/kgTS with disintegration degree of 58.84%. During the operation of aerobic digester, VS/TS ratios of digesters fed with disintegrated sludge decreased indicating that disintegration methods could obviously enhance aerobic digestion performance. The highest reduction in volatile solids was 75% in the digester fed with ultrasound+potassium permanganate disintegrated sludge at the end of the operation compared to digester fed with raw sludge. Total Nitrogen (TN) and Total Phosphorus (TP) levels in sludge supernatant increased with this combined method significantly. Besides, it promoted the production of ${\bullet}OH$, thus enhancing the release of Carbon (C), Nitrogen (N) and Phosphorus (P) from the sludge. Disintegration with all methods used in this study could not improve Capillary Suction Time (CST) reduction in disintegrated digesters during the operation. The results demonstrated that the combined ultrasound treatment and potassium permanganate oxidation method improves the biodegradability compared to control reactor or their single application.