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

• Journal of the Korean Applied Science and Technology
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• v.34 no.3
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• pp.436-442
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• 2017

This study was conducted to develop a wastewater treatment system to remove organic matter, nitrate nitrogen, and phosphate ion in synthetic wastewater. COD was removed almost 100% by the oxidation reaction of HClO and nitrate nitrogen was reduced to ammonia by electrolysis treatment, but ammonia was reoxidized into nitrate nitrogen by HClO treatment. Ammonia was removed almost 100% by heating evaporation and no ammonia was reoxidized into nitrate by HClO treatment. Phosphate ion could be removed by precipitation treatment by forming metal complex according to pH. Through electrolysis treatment and HClO treatment, removal efficiencies of COD 99.5%, nitrogen 97.3% and phosphorus 91.5% were obtained.

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

• Environmental engineer
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• v.23 s.240
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• pp.30-35
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• 2006

• 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 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.

• Journal of Aquaculture
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• v.7 no.3
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• pp.177-187
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• 1994

The objective of the present study were to evaluate nitrification characteristics and determine optimum treatment conditions of three phase fluidized bed reactor for recycling water treatment of aquaculture. When the loading rates were 2.739-0.086kg $COD/m^3/day$ and 1.575-0.128kg $NH_4\;^+-N/m^3/day$, COD and ammonia removal efficiencies were $56.3-94.7\%\;and\; 67.3­92.6\%$, respectively. The maximum removal rates of COD and ammonia were 1200mg/l/day and 488mg/l/day, respectively. Ammonia removal rates were more than $90\%$ beyond 1hr HRT. The ammoniaremoval efficiency was sensitive to the variation of media concentration and air flowrate.

• Korean Journal of Microbiology
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• v.46 no.1
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• pp.27-32
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• 2010

We used phototrophic bacteria to remove low concentrated organic materials (CODCr), nitrogen and phosphorus. We applied $COD_{Cr}$ 37.3 mg/L, $NH_3-N$ 4.0 mg/L, and $PO_4^{3-}-P$ 1.0 mg/L (C:N:P=100:10:1) in the batch test, and the removal efficiencies were shown as follow: $COD_{Cr}$ 87.4%, $NH_3-N$ 46.3%, $PO_4^{3-}-P$ 79.7%. The aerobic process with mixed phototrophic bacteria, ceramic media, and media KSP01 showed the removal efficiencies of $COD_{Cr}$, $NH_3-N$, and $PO_4^{3-}-P$, each as 72.7% and 79.2%, respectively in the lab-scale reactor. The maximum $PO_4^{3-}-P$ removal efficiency reached 92.6% by adjusting pH. There were three conditions used to remove $NH_3-N$. The highest removal efficiency was 98.5% with 10.2 L/min of aeration in 1-2 reactors, and the result of applying river-water showed the high removal efficiency of $NH_3-N$ (82.8%). Therefore, this purification system may be useful to control nitrogen and phosphorus at low concentration in field.

• Journal of the Korean Applied Science and Technology
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• v.36 no.2
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• pp.417-423
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• 2019

A new wastewater treatment system was developed to remove nitrate nitrogen and phosphorus in synthetic wastewater through electrochemical treatment. Higher removal efficiencies of nitrate nitrogen were obtained as the current density increased. Higher nitrate removal efficiencies were obtained when the switching interval was 1 min. The total phosphorus removal rate according to the current density was found to be over 90% without being greatly affected by the change in current density and interval, and the total removal rate increased with increasing switching time (1 min interval). On the other hand, COD was not treated by electrochemical treatment, but rather increased as the electrode eluted. Also, the consumption rate of the electrode was smaller as the switching interval was shorter. Finally, removal efficiencies of 98.1% of nitrate and 90% of phosphorus were obtained through electrochemical treatment (current density $50mA/cm^2$, switching interval 1 min, flow rate 540 mL/min).

• Bulletin of Korea Environmental Preservation Association
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• v.24 no.5_6
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• pp.51-56
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• 2002