• Environmental Engineering Research
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• 제19권2호
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• pp.175-184
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• 2014

Weirs are conventional structures that control water level and velocity in streams to facilitate water resource management. Despite many weirs built in streams, there is little information how weirs change hydrology regime and how that translates to sediment and phosphorus (P) responses. This study evaluated the influence of weirs on P retention and mobilization in an urban tributary of the Han River in Korea. Total P concentrations in sediments upstream of weirs were higher than the downstream site, mainly due to the increase of potentially available fractions (labile P and aluminum- and iron-bound P) (p < 0.05). Equilibrium phosphorus concentrations ($EPC_o$) were lower than soluble reactive phosphorus (SRP) concentrations of stream waters, but there was an increasing trend of sediment $EPC_o$ upstream of weirs compared to the downstream site (p < 0.001) indicating a greater potential for P release upstream of weirs. Sediment core incubation showed that SRP release rates upstream of weirs were higher than the downstream site under anoxic conditions of the water column (p < 0.01), but not under oxic conditions. SRP release rates under anoxic conditions were greater than that measured under oxic conditions. Un-neutral pH and increased temperature could also enhance SRP release rates upstream of weirs. We conclude that weirs can increase P retention within stream sediments and potentially promote significant P releases into waters, which in turn cause eutrophication.

• 한국물환경학회지
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• 제18권2호
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• pp.213-220
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• 2002

In this study the effects of initial pH, temperature, dissolved oxygen concentration, and sediment depth on the release of phosphorus from sediment in Lake Sihwa were investigated. No phosphorus release occurred at $10^{\circ}C$ for all pH values. DO concentrations were decreased and equilibrium was obtained 4-8 days after phosphorus release started. The DO concentrations were less than 1 mg/L. Sediment depth had little effect on phosphorus release rate. In order to control the released phosphorus, raw sludge and chalk were used. Results showed that a portion of phosphorus was removed by adsorption to chalk and raw sludge. About 90 % phosphorus removal was observed using sludge and calcinated chalk from the water sample in Lake Sihwa.

• 한국환경보건학회지
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• 제26권4호
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• pp.97-104
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• 2000

The purpose of this is made an examination of phosphorus loading model for eutrophication response in the Yongsan lake. For the model, we measured the total amount of nutrients derived from the Yongsan river watershed, inflow rate to the Yongsan lake, water quality, and water budget from January to December in 1999. The total amount of precipitation in the Yongsan river watershed was 4,951.7$\times$10$^{6}$ ㎥/y and inflow amount was 2,569.7$\times$10$^{6}$ ㎥/y, therefore the outflow rate of the Yongsan river watershed was 51.9%. The develop loading of total nitrogen was 86,928.1kg/d and that of total phosphorus was 22,007.6kg/d at the Yongsan river watershed, But, as the inflow loading of total nitrogen was 33,962kg/d and the inflow loading of total phosphorus was 2,218kg/d to the Yongsan lake. so each infolw rate was 39.0% and 10.1%. The hydraulic residence time was 34days, total phosphorus loading [L(P)] on the surface area was 23.398g/㎥/y, the hydraulic load( $Q_{s}$) of inflow water was 74.269m/y, the reserve rate of phosphorus in the lake was 0.359, and the settinh velocity of phosphorus was 0.114m/d at the Yongsan lake. Mathematical model of phosphorus loading to estimate the responses of eutrophication at the Yongsan lake is [ $P_{j}$] = 0.838 [L(P)/Q.(1+√ $T_{w}$)$^{-1}$ ] . ] . .

• 한국환경과학회지
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• 제9권1호
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• pp.95-99
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• 2000

Laboratory experiments were performed to investigate the effects of various factors on the phosphorus removal by electrolysis with aluminium electrodes. The efficiency of phosphorus removal increases with increasing of voltage applied, surface area of electrodes and electrolyte concentration, and decreasing of electrode distance. The phosphorus removal was not affected by the connection number of an electric circuit. The amount of aluminium ion eluted from electrodes according to Faraday's law was 4.47 mg and the A/P mole ratio was 2.14 at the electric current value of 20 mA.

• 한국수산과학회지
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• 제23권3호
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• pp.192-197
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• 1990

낙동강 하구호의 수질관리 모델링을 위한 인자중의 하나를 구하기 위해 하구호내의 저층 적물로부터의 인의 용출특성에 대한 연구를 수행하였다. 저질에 존재하는 POP와 PIP의 총인에 대한 존재비율은 각각 $34.7\%,\;65.7\%$이었고, 대부분의 PIP 는 NAI-P($61.1\%$)와 Apatite-P($30.0\%$)의 형태로 존재하였다. 회분식 반응조를 이용하여 수온과 용존산소의 환경조건에 따라 산출한 인의 용출속도는, 높은 수온과 혐기적 조건에서는 $39.4mg/m^2/d$로 저질로부터 많은 양이 용출되며, 낮은 수온과 호기적 조건에서는 $-4.4mg/m^2/d$로 수층으로 부터 제거되는 것으로 나타났다. 이상의 결과에서 낙동강 하구호내의 저질이 인의 내부부하원으로 작용할 가능성이 매우 크며 하구호의 인 농도 증가에 직접적인 영향을 끼치고 있음을 알 수 있다.

• 한국물환경학회지
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• 제21권6호
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• pp.664-668
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• 2005

An experimental study for the comparison of nitrogen and phosphorus removal efficiencies between $A^2/O$ and modified Phostrip (M-Phostrip process) were carried out with bench-scale reactors. In case of nitrogen removal efficiencies both of processes showed similar ones when influent organic loadings were high. However, M-phostrip process was more effective than $A^2/O$ at low organic loadings. This is why M-phostrip process consumes the whole mass of influent organics as a carbon sources for denitrification in anoxic reactor but the anoxic reactor of $A^2/O$ process utilizes the residual carbon followed by consumming a part of influent carbon for phosphorus release in anaerobic reactor. $A^2/O$ process required the influent COD/T-P and COD/TKN ratios were more than 56 and 10, respectively, to take place the phosphorus release in anaerobic process and phosphorus uptake in oxic process. However, the luxury uptake of phosphorus in M-phostrip process was not affected by influent COD/T-P and COD/TKN ratios and the adverse effect of nitrate in return sludge introduced to the p-stripper from the 2nd clarifier was not significant due to the configurational advantage of the p-stripper.

• 유기물자원화
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• 제30권1호
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• pp.33-39
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• 2022

혐기성 소화 슬러지 탈리여액을 대상으로 마그네슘 공급원이 인산암모늄마그네슘(MAP) 결정화에 의한 인산염 회수에 어떠한 영향을 미치는지 알아보기 위해 회분식 실험을 실시하였다. 마그네슘 공급원으로 염화마그네슘, 수산화마그네슘 그리고 산화마그네슘을 사용하여 다양한 pH (7.5, 8.0 및 8.5) 조건 및 Mg/P 몰 비율(1.0, 1.5, 2.0 및 2.5)에서 인산염 회수를 실시하였다. 그 결과, 마그네슘 공급원과 관계없이 pH 조건과 Mg/P 몰 비율이 높을수록 인산염 회수율이 증가하였다. pH가 가장 낮은 7.5의 조건에서는 Mg/P 몰 비율이 증가할수록 인산염 회수율이 증가하였는데 산화마그네슘, 수산화마그네슘, 염화마그네슘의 순으로 높았다. 그러나 pH가 가장 높은 8.5의 조건에서는 Mg/P 몰 비율과 관계없이 모든 마그네슘 공급원에서 90% 이상의 높은 인 회수율을 얻을 수 있었다. 따라서 낮은 pH 조건에서도 높은 인산염 회수율을 얻을 수 있었던 수산화마그네슘과 산화마그네슘이 경제적인 측면뿐만 아니라 효율적인 측면에서도 염화마그네슘을 대체할 수 있을 것으로 기대된다.

• Carbon letters
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• 제15권4호
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• pp.277-281
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• 2014

A series of high capacity soft carbons with different phosphorus contents were successfully prepared by carbonizing petroleum cokes treated with hypophosphorous acid at $900^{\circ}C$. The effect of phosphorus content on the electrochemical performance of the soft carbons was extensively investigated. The P-doped soft carbons exhibited greatly enhanced discharge capacities and outstanding rate capabilities with increasing phosphorus content. In addition, the influence of temperature on the electrochemical behaviors of the soft carbons was investigated in a wide temperature range of $25^{\circ}C$ to $50^{\circ}C$. Surprisingly, the electrochemical properties of the pristine and P-doped soft carbons were highly sensitive to the operating temperature, unlike conventional graphite. The pristine and P-doped soft carbons exhibited significantly high discharge capacities of 470 and 522 mAh/g, respectively, at a high temperature of $50^{\circ}C$.

• 분석과학
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• 제24권4호
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• pp.304-309
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• 2011

본 연구는 물과 토양에서 pH와 상등액을 변화 시켜었을 때 인과 탁도의 행태에 관해 연구 하였다. 탁도의 인 용출율은 pH 4 이하 또는 pH 7 이상일 때 증가 되었고, 토양으로 부터 탁도 발생율은 pH가 증가하면 증가하며, pH 4 보다 커지면 급격히 상승한 후 pH 6 이상에서 안정화된다. 용존성인은 2-24시간까지 증가 후 안정화 됐고, 탁도 역시 24 시간까지 정점에 도달한 후 96시간까지 감소됨. 시료상 등수를 교체를 하면 용존성인과 탁도는 감소한다. 시료를 pH 6에서 pH 10으로 증가시키고, 상등액 교체를 1회에서 4회로 동시에 증가시킬 때 용존성인과 탁도의 행태는 유사하다. 이 결과로 용존성인과 탁도는 pH와 직접적인 연관이 있다고 사료되며, 호수는 pH 7-10 정도이기 때문에 이 결과는 대단히 중요하다.

• 한국가금학회지
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• 제27권1호
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• pp.19-23
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• 2000

The effects of microbial phutase on laying performance and phosphorus utilization were examined at different levels of dietary nonphosphorus(NPP) in 320 23-week-old Hy-line brown hens for 12weeks. Diets were formulated 0.275%(T1), 0.220%(T2), 0.165%(T3) of NPP levels, and supplemental microbial phytase was 300DPU/kg diet constantly. Conventional diet(C) was formulated 0.275% NPP level without microbial phytase. Egg production and egg mass were higher in T2 than the others (p<0.05), and average egg weight was higher in T1 than the other (p<0.05). Egg productivity was tended to increase with supplemental phytase compared to conventional diet. Daily feed intake a hen also increased in T2 (p<0.05). Feed conversion ratio was improved slightly without significant difference. Eggshell breaking strength and thickness were not different significantly among the treatments. Haugh unit and yolk color were also not different. Calcium and phosphorus retention in body increased in T2 (p<0.05), but dry matter and nitrogen retention were not different significantly. Differences in nitrogen and calcium excretions were not found among the treatments. But phosphorus excretion decreased in order of dietary phosphorus levels with supplement phytase compared to C (p<0.05). Tibial ash, calcium and phosphorus were similar among the treatments. In conclusion, supplemental microbial phytase in laying diet may help to utilize phytase phosphorus, and could decrease NPP intake.