• 한국환경보건학회지
• /
• 제28권1호
• /
• pp.93-97
• /
• 2002

The aim of this study was to evaluate on the removal effect of total nitrogen and phosphorus with municipal wastewater in ultrasonic nutrient removal (UNR) process using ultrasonic sludge carbon source. The removal efficiency for total nitrogen was 44.2% at biological nutrient removal (BNR) process, 50.8% at UNR process. The removal efficiency for total phosphorus was 45.6% at BNR process, 46.2% at UNR process. The removal of nitrogen was effectively influenced by ultrasonic sludge carbon source.

• 한국환경보건학회지
• /
• 제25권3호
• /
• pp.70-76
• /
• 1999

A laboratory experiment was performed to investigate the phosphorus removal using the activated sludge-electrolysis reactor which consisted of A$^2$/O system and aluminium electrodes as cathode and anode. In this system, the phosphorus was removed by aluminium ion, which was eluted from aluminiumelectrodes by electrolysis. In the batch experiments, when the current densities were 0.026, 0.052 and 0.08 A/dm$^2$, the phosphorus removal efficiencies for synthetic sewage were 66.4, 86.4 and 98.7% respectively. These results showed that the phosphorus removal efficiency increased with the increase of the current density. When the current values were 13, 26 and 40 mA respectively, the amounts of Al$^{3+}$ eluted from electrodes according to Faraday's law were 0.049, 0.07 and 0.12 g and Al/P mole ratio were 1.1, 2.0 and 3.41. In the continuous experiments, As hydraulic retention time(HRT) increased, COD and total nitrogen(T-N) removal efficiencies for domestic sewage increased. The average phosphorus removal rates of the activated sludge-electrolysis system were 97, 91, 80 and 80% at the HRT of 48, 24, 18 and 12 hours, respectively. Especially, the phosphorus removal rate in the activated sludge system with aluminium electrodes was higher than that in the system without aluminium electrodes.

• 상하수도학회지
• /
• 제25권3호
• /
• pp.367-373
• /
• 2011

Mechanism of rapid mixing effect on chemical phosphorus removal is evaluated in this study. Assuming that chemical phosphorus removal is unaffected by mixing time, only rapid mixing intensity is evaluated. In order to find out the mechanism, it is hypothesized that rapid mixing affects the Al hydrolysis speciation, and that formation of more monomeric species ($Al^a$) results in better removal of phosphorus. According to a ferron assay, more $Al^a$ formed at higher mixing intensity than at lower intensity. Subsequent experiments revealed that better phosphorus removal was obtained at higher intensity than at lower intensity, in terms of the molar ratio of $Al_{added}/P_{removed}$. The proposed hypothesis was proved in this study. Chemical phosphorus removal is affected by rapid mixing intensity due to its effect on the Al hydrolysis speciation.

• 한국환경과학회지
• /
• 제8권6호
• /
• pp.705-710
• /
• 1999

The fundamental experiments on the phosphorus removal from water were carried out by the batch and continuous reactors which used aluminium and copper plate. In this systems, the phosphorus was removed by aluminium ion generated with the electrochemical interaction (pitting corrosion) of aluminium and copper. In the batch experiments, the efficiencies of phosphorus removal increased when the surfaces of aluminium and copper plate were brushed. The phosphorus removal by aluminium ion was affected the copper plate and NaCI in this system. The optimal pH values were 5 and 6 for the phosphorus removal. The efficiency of phosphorus removal increased with increasing NaCI concentration, surface area of aluminium and copper plate. The $CUSO_4{\cdot}5H_2O$ instead of copper plate could be used as Cu source. The effluent $PO_4-P$ concentration as low as 2 $mg/{\ell}$ could have been obtained during the continuous experiment at HRT of 48 hrs.

• 한국물환경학회지
• /
• 제25권6호
• /
• pp.916-921
• /
• 2009

This study was aimed to both enhance the fluoride removal and to reduce the phosphorus removal in treating semiconductor wastewater using $Ca(OH)_2$ at low pH so as to facilitate struvite crystallization reaction. The struvite crystallization could be introduced after fluoride removal by retaining the phosphorus source. As the results, the method applied in this study achieved high fluoride removal efficiency (about 91%) with retardation of phosphorus removal at pH 4, compared to conventional methods where the removal of fluoride and phosphorus were done at pH 11. Therefore, the fluoride removal at low pH would contribute to the enhancement of nitrogen and phosphorus removals in a consecutive struvite crystallization reactor. Treatment of semiconductor wastewater at low pH using $Ca(OH)_2$ also had lower (about 20%) water content of precipitated sludge compared to conventional method. As the molar ratio of Ca to F increased the removal efficiencies of fluoride and phosphorus increased. Although the amount of seed dosage didn't affect the removal of fluoride and phosphorus, its increase reduced the water content of precipitated matter. Finally, considering consecutive struvite reaction, the optimum condition for the removal of fluoride and phosphorus was as follow: pH: 4, the molar ratio of Ca:F: 1:1.

• 상하수도학회지
• /
• 제12권2호
• /
• pp.59-66
• /
• 1998

The feasibility of usage of sludge from water treatment plant and chalk from schools and institutes was investigated to remove the phosphorus in the lakes which induce the eutrophication every year. In this study phosphorus removal efficiencies of sludge and chalk were investigated by changing various factors. Higher phosphorus removal efficiency using larger particle size of chalk was observed which means that the surface area is not an important factor in removing phosphorus in aqueous phase. The proper shaking time and temperature were 2 hours and $25^{\circ}C$, respectively. The removal efficiency using sludge from water treatment plant was almost 100%, which is similar to those of CaO and $Ca(OH)_2$. It means that sludge can be reused in removing phosphorus. It was also found that chalk was better in removing phosphorus under alkaline condition and sludge was better under acidic condition. About 75% phosphorus removal efficiency was observed using sludge from the water sample in Lake Sihwa.

• 한국물환경학회지
• /
• 제18권3호
• /
• pp.291-301
• /
• 2002

In this study, nutrients treatment by sequencing batch reactors(SBR) was performed. Nitrogen and phosphorus removal efficiencies were evaluated by changing SRT and mixing/aeration ratio. Not only nitrogen but also phosphorus removal patterns were investigated through track studies on 1 cycle. As SRT was fixed and mixing/aeration ratio was changed, maximum nitrogen removal efficiency was 87.6% at mixing/aeration ratio 0.67. Phosphorus removal efficiencies were more than 85.5% except no mixing condition. As mixing/aeration ratio was fixed and SRT was changed, nitrogen removal efficiencies were 70.5~79.8%, which represented slight changes, while phosphorus removal efficiencies were 49.0~97.3%, which represented sharply decreasing tendency at less than 20 day. Both phosphorus release rate k and maximum phosphorus release rate $P_{max}/M$ were are decreased as SRT was decreased, but they were not affected by mixing/aeration ratio. It was found that there is a linear relationship between ortho-phosphate uptake and maximum ortho-phosphate release.

• 생명과학회지
• /
• 제15권4호
• /
• pp.584-589
• /
• 2005

담체인 황토볼와 Chromobacterium WS 2-14을 이용하여 F-STEP공정(혐기${\rightarrow}$ 호기${\rightarrow}$ 무산소)에서 실제폐수에 존재하는 인산을 효율적으로 제거하기 위해 최적 황토볼 크기 및 소성 온도, 폐수의 초기 pH,폐수의 초기 인산염 농도, 운전온도, 그리고 통기를 검토했다. 최적 조건은 다음과 같다. 황토볼 크기 및 소성 온도, $2\~4mm,\;960^{\circ}C$; 실페수의 초기pH, 6.0; 실페수의 초기 인산 농도, 5.0mg/1. 운전온도, $30^{\circ}C$; 그리고 통기, 5.0L/min등이 얻어졌다. 그리고 최적 운전조건을 이용해서 pilot test을 65일 동안 진행했다. 인산 평균 제거율은 $92.0\%$였고. 또한 최종 유출수에서 COD와 BOD의 평균 제거율은 각각 77.1와 $74.2\%$였으며, SS의 경우는 평균 제거율이, $86.4\%$였다. 이상의 결과로부터 황토볼을 담체로 이용한 Biofilter System은 실제폐수에 존재하는 인산 제거 가능성을 암시했다.

• 한국환경보건학회지
• /
• 제35권2호
• /
• pp.116-123
• /
• 2009

Laboratory scale experiments were conducted to investigate the removal characteristics of nitrogen and phosphorus by the variation of aeration time in four sequencing batch reactors (SBRs). In R1 which has the shortest aeration time as 1 h, MLVSS concentration in reactor decreased by the wash-out of biomass because of the poor sedimentation. The TOC removal efficiencies were almost similar in 3 reactors except R1. At the low aeration time as 1 h, the nitrification was severely inhibited by the deficiency of oxygen. ${NH_4}^+$-N removal efficiency was decreased by the decrease of aeration time. At the aeration time over 2 h, the phosphorus removal efficiency was not affected by the variation of aeration time. The nitrification was inhibited but the phosphorus release and uptake was not inhibited by the decrease of low aeration time. Therefore, we can see that the phosphorus removal microorganisms are superior to nitrification microorganisms in oxygen utilization.

• 한국환경과학회지
• /
• 제15권6호
• /
• pp.571-577
• /
• 2006

This study make a comparison between the phosphorus removal performance of FNR(Ferrous Nutrient Removal) process and A/O process by the laboratory experiments. For simultaneous removal of phosphorus, iron electrolysis was combined with oxic tank. Iron precipitation reactor on the electrochemical behaviors of phosphorus in the iron bed. The phosphorus removal in FNR process was more than A/O process. Iron salts produced by iron electrolysis might help to remove COD and nitrogen. And the demanded longer SRT is the more removes the removes COD, nitrogen, and phosphorus. Also, FNR process of sludge quantity more reduce than A/O process to input cohesive agents.