• 상하수도학회지
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• 제34권6호
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• pp.437-443
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• 2020

Biological phosphorus removal is accomplished by exposing PAO(phosphorus accumulating organisms) to anaerobic-aerobic conversion conditions. In the anaerobic condition, PAO synthesize PHB(polyhydroxybutyrate) and simultaneously hydrolysis of poly-p resulting phosphorus(Pi) release. In aerobic condition, PAO uptake phosphorus(Pi) more than they have released. In this study, cyanobacteria Synechococcus sp., which is known to be able to synthesize PHB like PAO, was exposed to anaerobic-aerobic conversion. If Synechococcus sp. can remove excess phosphorus by the same mechanism as PAO, synergistic effects can occur through photosynthesis. Moreover, Synechococcus sp. is known to be capable of synthesizing PHB using inorganic carbon as well as organic carbon, so even if the available capacity of organic carbon decreases, it was expected to show stable phosphorus removal efficiency. In 6 hours of anaerobic condition, phosphorus release occurred in both inorganic and organic carbon conditions but SPRR(specific phosphorus release rate) of both conditions was 10 mg-P/g-MLSS/day, which was significantly lower than that of PAO. When converting to aerobic conditions, SPUR(specific phosphorus uptake rate) was about 9 mg-P/g-MLSS/day in both conditions, showing a higher uptake rate than the control condition showing SPUR of 6.4 mg-P/g-MLSS/day. But there was no difference in terms of the total amount of removal. According to this study, at least, it seems to be inappropriate to apply Synechococcus sp. to luxury uptake process for phosphorus removal.

• 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.

• 한국환경과학회지
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• 제28권10호
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• pp.851-861
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• 2019

In this study, we performed a sediment elution experiment to evaluate water quality in terms of phosphorus, as influenced by the dissolved oxygen consumed by sediments. Three separate model column treatments, namely, raw, calcined, and sonicated oyster shell powders, were used in this experiment. Essential phosphorus fractions were examined to verify their roles in nutrient release from sediment based on correlation analyses. When treated with calcined or sonicated oyster shell powder, the sediment-water interface became "less anaerobic," thereby producing conditions conducive to partial oxidation and activities of aerobic bacteria. Sediment Oxygen Demand (SOD) was found to be closely correlated with the growth of algae, which confirmed an intermittent input of organic biomass at the sediment surface. SOD was positively correlated with exchangeable and loosely adsorbed phosphorus and organic phosphorus, owing to the accumulation of unbound algal biomass-derived phosphates in sediment, whereas it was negatively correlated with ferric iron-bound phosphorus or calcium fluorapatite-bound phosphorus, which were present in the form of "insoluble" complexes, thereby facilitating the free migration of sulfate-reducing bacteria or limiting the release from complexes, depending on applied local conditions. PCR-denaturing gradient gel electrophoresis revealed that iron-reducing bacteria were the dominant species in control and non-calcined oyster shell columns, whereas certain sulfur-oxidizing bacteria were identified in the column treated with calcined oyster powder.

• 한국항해항만학회지
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• 제36권6호
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• pp.513-519
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• 2012

오염 원인 물질의 해양 내 거동에 대한 파악은 환경 변화에 따른 부영양화 등 해양 수질 오염에 대한 예측 및 대응 방안 선정을 위한 전제 조건이다. 본 연구에서는 부영양화 원인 물질인 인의 해양퇴적물에서 해수로의 용출 특성을 조사하였다. 검토된 환경 조건은 pH 7-9, 온도 10-$20^{\circ}C$, 용존 산소 농도(dissolved oxygen, DO) 0.7-7.0 mg/L 였다. 생물학적 요인을 배제한 조건에서 회분식 실험을 통해 구해진인 용출 자료는 1차 반응식으로 해석되었으며, 환경 조건의 영향은 통계학적 방법을 통해 정량화 되었다. 해양 퇴적물로부터 해수로의 인 용출은 pH와 온도가 높고 DO가 낮을수록 증가하였다. 1차 반응 평형 농도 기준으로 검토된 범위의 pH 증가, 온도 증가, DO 감소는 각각 인용출을 2-3배 증가시켰다.

• 한국농공학회논문집
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• 제58권2호
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• pp.1-9
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• 2016

This study aims to assess the effectiveness of activated carbon (AC) and crushed concrete (CC) as capping material to block the release of nitrogen, phosphorus, and organic substance from reservoir sediments. The efficiency of AC and CC as capping material was evaluated in a reactor in which a 1 or 3 cm thick layer of capping materials was placed on the sediments collected from Mansu reservoir in Anseong-city. Dissolved oxygen (DO) concentration, total nitrogen (T-N), total phosphorus (T-P), and chemical oxygen demand (COD) concentration in reservoir water above the uncapped sediments and capping material were monitored for 45 days. The release rate of T-N was in the following increasing order: AC 3 cm ($1.18mg/m^2{\cdot}d$) < CC 1 cm ($2.66mg/m^2{\cdot}d$) < AC 1 cm ($2.94mg/m^2{\cdot}d$) < CC 3 cm ($3.42mg/m^2{\cdot}d$) < uncapped ($4.59mg/m^2{\cdot}d$). The release rate of T-P was in the following increasing order: AC 3 cm ($0mg/m^2{\cdot}d$) $${\approx_-}$$ CC 3 cm ($0mg/m^2{\cdot}d$) < CC 1 cm ($0.03mg/m^2{\cdot}d$) < AC 1 cm capped ($0.07mg/m^2{\cdot}d$) < uncapped ($0.24mg/m^2{\cdot}d$). The release of nitrogen and phosphorus were effectively blocked by AC capping of 3 cm thickness, and CC capping of 3 cm thickness effectively controlled the release of phosphorus. The order of increasing COD release rate was as follows: AC 3 cm ($0mg/m^2{\cdot}d$) $${\approx_-}$$ CC 3 cm ($0mg/m^2{\cdot}d$) < CC 1 cm ($5.03mg/m^2{\cdot}d$) < AC 1 cm ($7.28mg/m^2{\cdot}d$) < uncapped ($10.05mg/m^2{\cdot}d$), indicating that AC and CC capping effectively interrupted the release of organic contaminants from the sediments. It was concluded that AC and CC could effectively block the release of T-N, T-P and COD release from contaminated reservoir sediments.

• 한국물환경학회지
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• 제31권5호
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• pp.533-542
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• 2015

In order to investigate the effect of internal loading from sediment on algal blooming at Chusori area in Daechung Reservoir, the amount and contamination level of sediment and the release rate of total phosphorus were analyzed. The sedimentary layer was consisted with two layers, and the average depth of upper and lower ones were 0.35 and 1.44 m, respectively. The fraction of inorganic phosphorus in the sediment was higher than that of organic phosphorus, and the fractions of phosphorus which responsible for internal loading were very high as in the range of 72.7 and 80.2% of inorganic phosphorus. The C/N ratio of sediment taken with core sampler indicated the organic compounds are originated from settled algae from water body. The average release rate of total phosphorus from sediment was $6.74({\pm}0.50)mg/m^2/day$. These results indicated that the internal loading from sediment contributes the excessive algal growth at Churosi area, and the countermeasures to improve the quality of sediments are required to manage algal blooming in Daechung Reservoir.

• 환경위생공학
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• 제17권1호
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• pp.75-80
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• 2002

This study was carried out to investigate release characteristics of phosphorus with DO, pH and temperature, to suppose its behaviour with time using mathematical model, and to under-stand its forms with pH. Released SRP was in inversely proportional to DO and it did few release in initial aerobic conditions, but it did actively with decreasing DO concentration. Also, its release was increased with increasing pH and temperature. It was found that relation between time and released SRP concentration was zero order reaction. As compared with k values in various pH and temp., they was $k_{15}>k_{25}$ in pH 6 but was $k_{15} in pH 7 and 8. Considering forms of phosphorus with pH, Resdi.-P & NAI-P increased but Ads.-P & Apt.-P decreased with increasing pH.

• 대한토목학회논문집
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• 제26권1B호
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• pp.125-130
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• 2006

본 연구에서는 호소 바닥의 저니에서 용출된 인이 수질에 악영향을 미치는 것을 제어하기 위하여 모래를 재료로 하는 캡핑을 저니 위에 포설할 때 기대할 수 있는 효과에 대하여 연구하였다. 실험실에서 제작된 칼럼을 외부 공기의 유출입이 없도록 폐쇄하고, 인의 농도가 높은 저니층에서 인의 용출로 인한 상등수의 인농도 변화와 모래로 이루어진 캡핑으로 격리 처리된 저니층에서 인의 용출로 인한 상등수의 인 농도 변화를 비교 분석하였다. 캡핑을 하지 않은 칼럼과 40 mm, 80 mm 캡핑 두께의 3가지 칼럼으로 시험을 수행하였고, DO, ORP, TP, $PO_4$-P를 측정하였다. 캡핑을 하지 않은 칼럼이 80 mm의 모래 캡핑을 한 칼럼보다 4배 이상의 TP농도 증가가 있은 반면 $PO_4$-P의 경우는 큰 차이가 나지 않았다. 본 실험조건에서 모래로 캡핑한 저니의 경우 캡핑이 되지 않은 저니 보다 인의 용출로 인한 상등수의 인의 농도를 저감할 수 있음이 확인되었다.

• 한국환경과학회지
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• 제28권5호
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• pp.511-520
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• 2019

This study was investigated to improve the phosphorus release and water quality by transformation of sedimentary P fraction for application of $CaO_2$. For the experiment, 0.5% (w/w) of $CaO_2$ was homogenized in the sediment and incubated with the control for 20 days. The analytical results showed that pH increased with $CaO_2$ and redox potential (ORP) was improved in the sediment of the reactor. The growth rate of chlorophyll-a was lower in the $CaO_2$ reactor and Dissolved Oxygen (DO) of overlying water maintained higher than that of the control. Total phosphorus (T-P) concentration in the overlying water increased from the initial concentration to 0.304mg/L in the control at 20 days. The reactor of $CaO_2$ was lowered by 29.3%. Ex-P, Fe-P and Ca-P in sediment P fraction were increased with the $CaO_2$. The formation of bound Fe-P and Ca-P in the sediments seemed to control the release of P by removing the Soluble Reactive Phosphorus (SRP) presented in the pore water. From the result, this indicated that the reduction of P release from the sediments seems to be effective in suppressing the eutrophication of P and improving the oxygen condition in the water quality with the application of $CaO_2$.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제2권2호
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• pp.169-179
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• 1998

This paper was performed to estimate interrelations between humus level of sediments and nutrient release from sediments in Dae-cheong reservoir. For investigations, sediments were sampled in June and October, in 1997 at fish farms, embayment, and the main stream of Dae-cheong reservoir. Items for investigation are as follows; water content, weight loss on ignition(IG), porosities of sediments, contents of element such as hydrogen, nitrogen, carbon, and nutrient release rates. Water contents and porosities were measured to conjecture the physical trait and grain size trait. Weight loss on ignition was measured to determine the contents of organic substance. For determination of the humus level of sediments, carbon and nitrogen contents were measured by elemental analyzer. As a result of elemental analysis, C/N ratio was determined in the range of $3.0\~13.1$. From the elemental analysis, humus level of Dae-cheong reservoir sediment was estimated from mesohumic state to oligotrophic state. For the determination of nutrient release rate, $PO_4-P$ and $NH_4-N$ concentrations of interstitial water and overlying water were measured. By using the concentration difference between interstitial water and overlying water and using the Fick's diffusion law, the release rates of phosphorus and nitrogen from the sediment samples were calculated. Release rates of nutrients which directly influence to the water quality were $0.05\~8.63mgP/m^2day$ and $4.99\~36.56mgP/m^2day$. It was found that release rate was measured higher in the 1st sampling period than in the 2nd sampling period. For the determination of phosphorus content in sediment, TPs were measured in 807\~1542{\mu}g/g$ in the 1st samling period and $677\~5238{\mu}g/g$ in the End samling period. Phosphorus release rate and phosphorus content were not interrelated each other.