• Microbiology and Biotechnology Letters
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• v.33 no.2
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• pp.136-141
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• 2005

A bench-scale feasibility study was conducted with solid farming feed to evaluate a treatment process for microbiological removal of nitrogen (N) and phosphorus (P). Strains, Bacillus sp. CK-10 and Bacillus sp. CK-13, were originally isolated from water samples of shrimp farming pond. Simultaneous removal of N/P in marine media was monitored in the co-cultures, CK-10 and CK-13. As the results, $400\;{\mu}M\;NH^{+}_4$ and $400\;{\mu}M\;NO^{-}_2$ were eliminated within 12 hours and $NO^{-}_3$ within 36 hours, and $500\;{\mu}M\;PO^{-3}_4$ was completely disappeared within 36 hours from the media. Cultures of CK-10 and CK-13 were applied for removal of N/P leached from shrimp farming fred. HPAEC-PAD system was used to analyze sugars in farming feed, resulting in resolution of various sugars including glucose, galactose, galatosamine, mannose, and fucose. $0.2\%$ (w/v) Pulp densities of the farming feed contained approximately $33.3\;{\mu}M\;NH^{+}_4,\;12.9\;{\mu}M\;NO^{-}_2.\;81.5\;{\mu}M\;NO^{-}_3\;and\;248\;{\mu}M\;PO^{-3}_4$ which could dissolved within 72 hours of leaching in aqueous solution followed by bacterial removal. Complete bacterial removal of N/P was achieved within 84 hours at $0.2\%$ of the feed in co-cultures, whereas single cultures removed to incompletion of N/P during the incubation period. This work demonstrated that test cultures, CK-10 and CK-13 showed effective removal of N/P derived from shrimp farming feed.

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

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.6
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• pp.690-695
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• 1994

Simultaneous removal of phosphorus and nitrogen from wastewater was studied by the anaerobic-aerobic system of activated sludge. In the anaerobic stage, most of the influent glucose was removed and orthophosphate was released, when the nitrate and/or nitrite concentration in the wastewater was almost zero. The amount of the released phosphorus was found to be directly proportional to the amount of the removed glucose. When the ratio of phosphorus to glucose in the influent was less than 0.04, the phosphorus in the wastewater was almost completely removed during the aerobic state. Under the anaerobic condition, activated sludge released phosphate and excess removal of phosphate occurred during the aerobic condition. Namely, the stress received in anaerobic period stimulated the uptake of phosphorus in aerobic period. The amounts of phosphorus release in the anaerobic and uptake in the aerobic stage were less in proportional to the concentration of $NO_x-N$. Further, if the initial ratio of $NO_2-N$/glucose was less than 0.37, the inorganic nitrogen in the influent could be completely removed.

• Journal of Industrial Technology
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• v.27 no.A
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• pp.203-209
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• 2007

본 연구는 목재로서 활용가치가 적은 수피(bark)를 활용하여 수질오염물질을 제거할 수 있는 여과 시스템에 대한 기초연구로서 소나무의 일종인 loblolly pine(Pinus taeda L.) 수피의 인 ($PO_4-P$) 흡착특성을 연구하였다. 실험에 사용된 수피는 입상형태로서 polyallylamine hydrochloride로 전처리하여 회분식 등온 흡착실험을 수행하였다. 회분식 등온흡착실험은 수용액 pH 3~pH 8범위에서, 인의 농도별(10, 20, 30, 40 mg/L)로 수행하였다. pH 5에서 가장 높은 인 제거 효율을 나타냈으며, 수용액의 pH는 실험 후 pH 3으로 감소하였다. 이러한 감소는 수피에 의한 phosphate의 흡착이 Lewis acid-base 반응으로서 이 과정에서 $H^+$의 방출로 인하여 나타난 현상인 것으로 여겨지며, 주된 반응 메카니즘은 더 연구할 필요성이 있다. 인 흡착은 초기에 빠른 속도로 진행되었으며 대략 200분 이후에 평형에 도달하였고, 시간이 지날수록 흡착양이 증가하는 경향을 보였다. 인의 흡착특성 결과는 Langmuir 등온흡착식과 Freundlich 등온흡착식으로 설명될 수 있으며, 등온흡착식 적용결과, 흡착제에 대한 최대 흡착능은 7.14 mg/g 이며 다른 흡착제와 비교하여 더 높았다. 실험결과와 모델에 의한 흡착능을 비교하고자 pseudo second-order model을 적용하여 흡착 동역학 상수를 구하였다. 또한 EDXA분석으로 회분식 흡착실험 후 수피와 인이 결합되어있는 것을 확인할 수 있었다.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.8
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• pp.774-779
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• 2010

The experimental results for the analysis of aluminum hydrolysis species with PACls (polyaluminum chloride) prepared by different basicity (r value) showed that monomeric Al species were reduced while polymeric Al species were increased with an increase in basicity for PACls. The PACl with 2.2 of r value contained the highest amount of polymeric Al species. According to the experimental results for the phosphorus removal, the alum and PACl (r=0), which consisted of mainly monomeric Al species, were the most effective for phosphorus removal. Therefore, it was concluded that the Al coagulant containing higher amount of monomeric or lower molecular Al species would be more beneficial for phosphorus removal.

• Journal of the Korean GEO-environmental Society
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• v.10 no.1
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• pp.43-48
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• 2009

This study was performed to investigate the characteristics of nutrient removal by Sequencing Batch Reactor (SBR) system, which could achieve high removal efficiencies of nitrogen and phosphorus and make it possible convenient management and operation. In this study, dissolved oxygen (DO), chemical oxygen demand (COD), nitrogen, and phosphorus in SBR system were examined by variation of anoxic-oxic phase repetition in order to optimize an operational method. The 1~4 times of anoxic-oxic phases (Run 1~4) were repeated during 1 cycle operation period. As the repetition frequency increased, it was more difficult to maintain DO condition enough for denitrification. The SBR system showed high COD removal efficiency more than 91% regardless of operational condition. About 68% of nitrogen removal rate was obtained in conditions of 2 or 3 times repetition of anoxic phases, in which NOx-N among discharged total nitrogen account for more than 99%. Approximately 40% of phosphorus was eliminated in the conditions of 1~3 times of anoxic phase repetition.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.8
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• pp.673-678
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• 2009

High-rate phosphorous removal by PAC (poly aluminum chloride) coagulation of A2O effluent was investigate to meet the stringent requirement of wastewater discharge from municipal wastewater treatment plant. A series of jar tests were conducted to find optimum coagulation condition and to enhance removal efficiency. The optimum volumetric concentration of PAC was 30 ppm (2.81mol Al/mol P by mol ratio). Only 17.2% of soluble P was removed for 30 minutes' settling without PAC addition, while this increased to 30.3% by dosing 10ppm PAC. It even increased conspicuously from 49.3% to 88.4% by increasing PAC dose from 20 ppm to 30 ppm. 92.4% of total P was removed by 30 ppm PAC, and the effluent concentration (0.3 mg/L) was acceptable for discharge. The optimum value of coagulation time, settling time, and pH were 4minutes, 20 minutes, and 7.0, respectively. It was not necessary to control pH of raw sample whose pH was 7.0. Soluble P removal was remarkably enhanced at pH 7.0. This implied that sweep floc formation by $Al(OH)_3$ was the main mechanism of coagulation for soluble P removal. Influent and effluent of secondary clarifier were tested for coagulation, and the effluent was better for high-rate P removal. It resulted in 0.18 mg/L of P and 95.4% of P removal by coagulation. It was favorable to recycle the treated water to coagulation tank and the optimum recycle ratio was 0.3.

• Korean Journal of Ecology and Environment
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• v.45 no.1
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• pp.102-109
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• 2012

In this study, the four different filter media (sponge, volcanic stone, activated carbon and magnesium hydroxide) were tested for the removal of algae and phosphorus in the two eutrophic water samples (natural water and artificial algal culture with BG-11 medium). These filter media were used in the column device as single or combined applications. The effect of the $Mg(OH)_2$ on phosphorus removal was examined using different particle sizes (<2 mm and >2 mm) and concentrations (0, 10, 50 and 100 g $L^{-1}$) of magnesium hydroxide. The removal efficiency of phosphate by magnesium hydroxide was increased with longer experimental time and higher concentration. However, there was no significant difference in the degree of phosphorus removal between any two particle sizes (1 mg P $L^{-1}$: F=0.109, P=0.685; 10 mg P $L^{-1}$: F=1.542, P=0.355). Among the four media, activated carbon showed the most potent effect on the removal of both algae and phosphorus. The highest removal efficiency of algae and phosphorus was obtained by combining four columns of each filter medium. Interestingly, integration of four filter columns showed higher removal efficiency than activated carbon alone. The highest removal efficiency by integrated filter columns seemed to be caused by a synergistic effect of combined activated carbon and magnesium hydroxide.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4910-4916
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• 2012

Changes of low concentrated nitrogen-phosphate removal efficiency were investigated in 4 strains of marine bacteria applied to ceramic media. Marine bacteria were isolated and identified from Gwangyang bay. Growth rates and removal efficiencies of $NH_3$-N of 4 strains of marine bacteria applied to ceramic media were increased approximately 3 fold and over 30% than control group, respectively. A. hydrophila and P. diminuta had highest ${NO_3}^-$-N and phosphate removal efficiencies, respectively. This results showed that ceramic media is very nice material for improvement of nitrogen-phosphate removal efficiency and isolated marine bacteria may be useful to control nitrogen-phosphate at low concentration in field.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.7
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• pp.730-737
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• 2010

It is very important to remove fluoride ion before treating semiconductor wastewater containing high concentration of ammonia, phosphates, and fluoride ions by struvite formation. Calcium ion was generally added for the removal of fluoride ion. However, calcium ions remained after removal of fluoride ion can deteriorate the performance of struvite crystalization. It should be removed completely before struvite formation. In this study, the effect of fluoride and calcium ion concentration on the struvite crystalization was investigated. Removal efficiencies of ortho-phosphate with struvite formation were more abruptly decreased than those of ammonium nitrogen, as increase of fluoride ion concentration in synthetic wastewater. The structures of struvite formed in synthetic wastewater containing calcium ion of up to 500 mg/L were identical. Purity of struvite was deteriorated as increase of calcium ion over 500 mg/L. Removal efficiencies of ammonium nitrogen were more decreased than those of phosphate ions as increase of cacium ion in synthetic wastewater.