• Fire Science and Engineering
• /
• v.29 no.6
• /
• pp.13-19
• /
• 2015

This study was performed to test the combustive properties of Pinus rigida specimens treated with phosphorus (P) and nitrogen (N) additives. Each Pinus rigida specimen was painted three times with 15 wt% P-N additive solutions at room temperature. After drying the treated specimens, the combustion properties were examined using a cone calorimeter (ISO 5660-1). The time to ignition (TTI) for the treated specimens was 90 to 148 s except for the specimen treated with PP/$4NH_4^+$, and the time to flameout (TF) was 556 to 633 s, which was longer than that of virgin plate. While the The specimens treated with P-N additives showed 12.5 to 43.4% higher mean heat release rate ($HRR_{mean}$) and 11.8 to 43.1% higher total heat release (THR) than virgin plate. The effective heat of combustion (EHC) was by 2.9 to 17.5% lower than that of virgin plate. It can thus be concluded that the combustion-retardation properties were partially improved compared to those of virgin plate.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2003.11b
• /
• pp.51-52
• /
• 2003

질소제거의 경우 포기 60min인 경우 90% 이상의 제거율을 보였으나, 인 제거를 위해 굴곡점 시간 이후 30분 이상의 비포기 상태를 유지하였을 때 낮은 제거율이 나타났다.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.25 no.6
• /
• pp.1006-1015
• /
• 1996

This study was carried out to investigate the effects of dietary calcium-salt, estrogen-treatment, and estrogen/calcium treatment on calcium, phosphorus and nitrogen metabolism. Female Sprague-Dawley rats with a body weight of 250~280g were underwent ovariectomy or sham-operation. The ovariectomized rats were divided into 9 different experimental groups including the saline-treated group, the estrogen-treated group, the high calcium salt-treated group, and the estrogen/calcium treated groups and fed for 6 weeks. Each group daily intake and excretion of calcium, phosphorus and nitrogen were measured and apparent digestibility and balance were also studied. The results were as follows: The excretion level of winn calcium was significantly higher the ovariectomized rats than the sham-operation group(p<0.01) and reduced with estrogen treatment but this difference was not statistically significant. Fecal loss of calcium was higher the ovariectomized rats than the sham-operation group(p<0.001). When the estrogen was treated, fecal loss was decreased and then apparent digestibility of calcium was increased. Calcium balance was significantly higher the high calcium treated groups than the control diet groups. The excretion level of urinary Phosphorus was higher the ovariectomized rats than sham-operation group, while these showed to be decreased in the calcium salt, the estrogen and the estrogen/calcium treated groups(p<0.01). Fecal loss of phosphrous was higher in the ovariectomized rats. When the estrogen was treated, the fecal loss was decreased in the avariectomized rat than that of other groups. The excretion level of urinary nitrogen was higher the ovariectomized rats than the sham-operation, while these showed to be decreased in the estrogen, the estrogen/calcium, and the estrogen gradually reduction/calcium intensification. Fecal loss of nitrogen was decreased in tile estrogen treated group. The results in this study showed that high calcium, estrogen/calcium and estrogen gradually reduction/calcium intensification in the ovariectomized rats enhanced calcium balance compared to the ovariectomized rats without calcium treatment, but little effects on the phosphorus and nitrogen balance.

• KSBB Journal
• /
• v.15 no.1
• /
• pp.14-21
• /
• 2000

In this study, algae cultivation using the photobioreactor has been applied to remove the nitrogen and phosphorus compounds in the wastewater of the livestock industry. The optimal ratio of nitrate and ortho-phosphate concentration was found for the enhancement of removal efficiency. To achieve the high density culture of algae, the photobioreactor consisted of optical fibers wes developed to get the sufficient light intensity. The light could be illuminated uniformly from light source to the entire reactor by the optical fibers. The structured kinetic model was proposed to describe the growth rate, consumption rate of nitrates and ortho-phosphates in algae culture. The self-organizing fuzzy logic controller incorporated with genetic algorithm was constructed to control the semi-continuous wastewater treatment system. The proposed fuzzy logic controller was applied to maintain the nitrated concentration at the given set-point with the control of wastewater feeding rate. The experimental results showed that the self-organizing fuzzy logic controller could keep the nitrate concentration and enhance algae growth.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2006.05a
• /
• pp.1400-1404
• /
• 2006

생물학적 질소, 인 제거 공정(이하 BNR)의 운전에 있어서 최적 유입수의 C/N(COD/TKN)비, SRT 및 온도의 범위 및 정량적 수치 등은 유기물 뿐 만아니라 질소, 인의 처리 효율에 있어서 매우 중요하다. 특히, 외국과 다른 저농도 유기물 특성을 보이는 국내 하수에 대해서는 BNR 공정의 선택과 설계 및 운전인자의 선별이 무엇보다도 중요한 역할을 한다. 본 연구에서는 IAWQ에서 제시한 ASM No.2d를 기초로 하여 만들어진 전산모형인 Envirosim사의 Biowin 프로그램을 시뮬레이션 도구로 활용하여, 국내 하수에 비교적 적용하기 용이한 A2/O 공정과 MUCT 공정에 대한 유기물, 질소 및 인처리 효율을 비교하고 유입수의 C/N와 SRT 및 온도에 따른 질소, 인 처리 특성과 유출수의 거동 등을 파악하였다. 시뮬레이션 결과, 국내 하수에서는 A2/O 보다는 MUCT 공정이 질소, 인 처리효율이 더 크게 나타났다. 온도와 SRT가 일정한 상태에서 C/N비는 7이상에서 TKN과 TP제거효율이 양호하게 나타났고, 온도와 C/N비를 일정한 조건에서는 SRT가 7일을 넘어서면 효율이 급격히 낮아지는 현상을 관찰할 수 있었다. 온도조건 실험에서는 $20^{\circ}C$이하, 특히 국내 하수처리장에 BNR 적용시 설게조건인 $13^{\circ}C$에 근접해서는 TKN의 제거효율은 급격히 떨어지는 반면에 인 제거효율이 상승하는 것으로 나타났다.

• Journal of Korean Society of Environmental Engineers
• /
• v.35 no.6
• /
• pp.449-455
• /
• 2013

The effect of recycling ratio and fixed media on nitrate and phosphate removal was investigated in a pilot-scale wastewater treatment unit using synthetic wastewater. Addition of fixed media increased nitrate removal from 45 to 58% while no noticeable change was observed for Chemical Oxygen Demand (COD) and phosphate removal (<5%). Nitrate removal efficiency also enhanced (Ca 7%) when the influent wastewater flow was doubled (2Q), however phosphate removal was decreased from 40.9 to 26.6% with the increasing recycling rate. The attached biomass analysis showed the presence of bacteria (73.4 $mg/cm^2$) on the surface of added media in anoxic reactor. Pseudomonas aeruginosa a common denitrifying bacterium dominated the bacterial growth (58%) in the anoxic reactor which was determined using Fluorescence In Situ Hybridization (FISH) analysis.

• Environmental engineer
• /
• v.19 s.186
• /
• pp.66-73
• /
• 2002

우리나라 하수의 특성이 유기물 농도가 질소 농도에 비하여 매우 낮기 때문에 외국의 종속영양 탈질 공법을 그대로 적용하기가 힘들며 적용한다 할지라도 외부탄소원을 넣어야 하므로 경제적인 처리는 불가능하다. 산업폐수의 경우에 있어서도 유기물농도가 질소농도에 비하여 낮은 폐수의 경우는 값비싼 외부탄소원을 넣어주어야 한다. 따라서 폐수 특성에 맞는 효율적이고 경제적인 질소화합물 제거 기술의 개발은 불가피하다. 따라서 종속영양탈질공정의 경제성 문제 및 기존의 황탈

• Environmental engineer
• /
• s.183
• /
• pp.70-77
• /
• 2001

우리나라 하수의 특성이 유기물 농도가 질소농도에 비하여 매우 낮기 때문에 외국의 종속영양 탈질 공법을 그대로 적용하기가 힘들며 적용한다 할지라도 외부탄소원을 넣어야 하므로 경제적인 처리는 불가능하다. 산업폐수의 경우에 있어서도 유기물농도가 질소농도에 비하여 낮은 폐수의 경우는 값비싼 외부탄소원을 넣어주어야 한다. 따라서 폐수 특성에 맞는 효율적이고 경제적인 질소 화합물 제거 기술의 개발은 불가피하다. 따라서 종속영양탈질공정의 경제성 문제 및 기존의 황탈

• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.1
• /
• pp.121-132
• /
• 2000

This study is to investigate the performance of a new BNR process using predenitrification scheme focusing on nitrogen removal and the possibility of adapting a computer simulation scheme in BNR process development. By using a pre-denitrification basin, higher $COD/NO_3-N$ ratio could be sustained in this BNR process. The results of the investigation showed a SDNR value of 9.04mg/gMv/hr. In the anoxic tank, the average value of SPRR of 6.25mgP/gMv/hr was observed to be very sensitive to SCOD load of influents. By calibrating internal parameters (stoichiometric and kinetic parameters) of the simulation model, the results of simulation for various BNR processes gave good agreement with observed data. The major adjustment was given with three parameters, maximum specific growth rate of heterotrophic biomass, short chain fatty acid (SCFA) limit, and phosphorous release rate. With the series of simulations on varying operational conditions, the simulation by computer program can be a useful tool for process selection, and design and operation of municipal wastewater treatment plant.

• Journal of the Korean Society for Environmental Technology
• /
• v.19 no.6
• /
• pp.493-502
• /
• 2018

The purpose of this study was to develop EM media for water treatment and to remove nitrogen and phosphorus which cause water algae boom in water system. The ideal mixing ratio of raw material such as clay: zeolite: vermiculite: activated carbon for manufacturing the EM media was 10: 2.5: 0.1: 2, and the calcination temperature was $700^{\circ}C$. The comparison of the physical properties of manufactures using distilled water and EM activated liquid as the material mixture are as follows. Porosity and density of EM media were 39.98 % and $1.13kg/m^3$, adsorption efficiencies of nitrogen and phosphorus were 69.3 % and 38.9 %. In contrast, porosity and density of distilled water media were 37.80 % and $1.11kg/m^3$, and adsorption efficiencies of nitrogen and phosphorus were 62.5 % and 37.8 %. The adsorption rate of nitrogen and phosphorus in the EM media was higher than that of the distilled water made one by 6.8 % and 1.1 %, respectively. The adsorption characteristics of the media to nitrogen and phosphorus could be expressed by the Freudlich adsorption isotherm. The change of calcination time did not affect the adsorption efficiency of phosphorus and nitrogen when EM media was formed, but it was considered that it affects the strength of media. Nitrogen removal efficiency was the best record in 4 hours of calcination time and 3 hours of calcination time in phosphorus removal efficiency.