• Journal of Korean Society of Water and Wastewater
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• v.27 no.3
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• pp.325-329
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• 2013

A result of estimating the effects of initial phosphorus concentration and nitrogen sources on removal of nitrogen and phosphorus in wastewater treatment using Scenedesmus dimorphus shows that there was no difference in microalgae growth amount and nitrogen removal amount by phosphorus concentration(5 ~ 60 mg/L). On the other hand, as initial phosphorus concentration increased, phosphorus removal amount was increased by luxury uptake of microalgae. Scenedesmus dimorphus preferred to ammonia when ammonia(40 mg/L) and nitrate(40 mg/L) are simultaneously presented and nitrogen removal rate of ammonia was high at approximately 20 mg/L/day.

• Journal of Environmental Science International
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• v.17 no.11
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• pp.1265-1271
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• 2008

Aerated submerged bio-film (ASBF) pilot plant has been developed. The presented studies optimized an inexpensive method of enhanced wastewater treatment. The objectives of this research were to describe pilot scale experiments for efficient removal of dissolved organic and nitrogen compounds by using ASBF reactor in plug-flow reactor (PFR) and improve understanding of dissolved organic matter and nitrogen compounds removal rates with dynamic relationships between heterotrophs and autotrophs in the fixed-film reactor. This research explores the possibility of enhancing the performance of shallow wastewater treatment lagoons through the addition of specially designed structures. This direct gas-phase contact should increase the oxygen transfer rate into the bio-film, as well as increase the micro-climate mixing of water, nutrients, and waste products into and out of the bio-film. This research also investigated the efficiency of dissolved organic matter and ammonia nitrogen removals in the ASBF. As it was anticipated, nitrification activity was highest during periods when the flow rate was lower, but it seemed to decline during times when the flow rate was highest. And ammonia nitrogen removal rates were more sensitive than dissolved organic matter removal rates when flow rates exceeded 2.2 L/min.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.10
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• pp.1893-1904
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• 2000

Nitrogen compounds are one of the major pollutants which cause eutrophication problems of the river or lake and red tides problems of the ocean. Currently available technologies for the removal of nitrogen compounds are mostly biological treatment. However, biological treatment is only effective for the wastewater which contains low concentration of nitrogen compounds. Leachate from solid waste landfill or industrial wastewater which contains high concentration of nitrogen can not be effectively treated by most of the currently available biological treatment technologies. With this connection. the objective of this study is to examine the applicability of ammonia stripping technology for the removal of high concentration of ammonia nitrogen compounds of the leachate from solid waste landfill. It can be concluded that ammonia stripping technology which was placed before the biological treatment process was very effective for the removal of high concentration of ammonium compounds. The chemical cost for the ammonia stripping was 16 percent higher than MLE process, so other methods like sludge recycling are needed for the reduction of operation cost. Further details are discussed in this paper.

• Membrane and Water Treatment
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• v.15 no.2
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• pp.59-66
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• 2024

This study evaluated the performance of a membrane aerated biofilm reactor (MABR) for nitrogen removal from a high-strength ammonia nitrogen-containing wastewater. The experimental setup consisted of four compartments that are sequentially anaerobic and aerobic to achieve complete nitrogen removal. The last compartment of the reactor setup contained a membrane bioreactor (MBR) to reduce sludge production in the system and to obtain a better-quality effluent. Continuous experiment over a period of 47 days showed that MABR exhibited excellent NH₄⁺-N removal efficiency (99.5%) compared to the control setup without MABR (56.5%). The final effluent NH₄⁺-N concentration obtained in the MABR was 2.99±1.56 mg/L. In contrast to NH₄⁺-N removal, comparable TOC removal values in the MABR and the control reactor (99.2% and 99.3%, respectively) showed that air supply through MABR is much more critical for denitrification than for organic removal. Further study to understand the effect of air supply rate and holding pressure on NH₄⁺-N removal in MABR revealed that an increase in both these parameters positively impacted reactor performance. These parameters are related to oxygen supply to the biofilm formed over the membrane surface, which in turn influenced NH₄⁺-N removal in MABR. Among the two different strategies to control biofilm over the membrane surface, results showed that scouring for a duration of 10 min on a weekly basis, along with mixing air supply, could be an effective method.

• Journal of Korean Society on Water Environment
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• v.38 no.4
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• pp.171-176
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• 2022

Recently, an autotrophic single-stage nitrogen removal (ASSNR) process based on the anaerobic ammonium oxidation (ANAMMOX) reaction has been proven as an economical ammonia treatment. It is highly evident that double-layered gel beads are a promising alternative to the natural biofilm for ASSNR because of the high mechanical strength of poly(vinyl alcohol) (PVA)/alginate structure and efficient protection of ANAMMOX bacteria from dissolved oxygen (DO) due to the thick outer layer. However, the thick outer layer results in severe mass transport limitation and consequent lowered bacterial activity. Therefore, the effects of the thickness of the outer layer on the overall reaction rate were tested in the biofilm model using AQUASIM for ammonia-oxidizing bacteria (AOB), nitrite-oxidizing bacteria (NOB) and ANAMMOX bacteria. A thickness of 0.5~1.0 mm is preferred for the maximum total nitrogen (TN) removal. In addition, a DO of 0.5 mg/L resulted in the best total nitrogen removal. A higher DO induces NOB activity and consequent lower TN removal efficiency. The optimal density of AO B and NO B density was 1~10% for a 10% ANAMMOX bacterial in the double-layered PVA/alginate gel beads. The real effects of operating parameters of the thickness of the outer layer, DO and concentrations of biomass balance should be intensively investigated in the controlled experiments in batch and continuous modes.

• Journal of Wetlands Research
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• v.19 no.4
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• pp.508-514
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• 2017

Water-bloom and red tide due to eutrophication have been overgrown and have caused various environmental problems. Recently, however, research on bid-diesel that can utilize algae as an energy source has been actively carried out. In particular, many studies variously have been conducted to utilize algal photosynthesis oxygen as a supply method for reducing the energy by an air blower in MWTP. In this study, a lab scale algae-nitrification reactor was operated to replace the oxygen required for nitrogen removal and the operation period was largely divided into three sections. In the first section, ammonia nitrogen removal efficiency was 24 ~ 38% according to the MLSS (Mixed Liquer Suspended Solid) concentration. In the second section, ammonia nitrogen removal efficiency was 38 ~ 50% according to the micro-algae concentration and in the last section ammonia nitrogen removal efficiency was 61 ~ 80% according to HRT (Hydraulic Retention Time). As a result, as the MLSS decreased and algae biomass increased, the ammonia nitrogen removal efficiency tended to increase, but the effect of Algae biomass was greater than that of MLSS.

• Journal of Wellbeing Management and Applied Psychology
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• v.6 no.3
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• pp.19-23
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• 2023

Purpose: High concentrations of nitrogen exist in food wastewater, and when nitrogen is not properly treated and discharged, it can cause eutrophication in the aquatic ecosystem. Research design, data and methodology: In order to remove nitrogen using sodium hypochlorite, the BNCR tank was designed and installed in the step behind the biological treatment tank, and the data of pH, TOC, and T-N were collected after about a month of demonstration. Results: As a result of operating the BNCR tank, total nitrogen decreased by about 83% on average. The total nitrogen in the second sedimentation tank before going through the BNCR tank must be removed and finally discharged after nitrogen is removed above the legal standard of 60 mg/L. Conclusions: If BNCR tank is added to the process currently applied to nitrogen removal and operated, ammonia nitrogen can be removed more efficiently. However, the disadvantage is that nitric acid nitrogen and nitric acid nitrogen cannot be removed. If these disadvantages are supplemented and optimized in the future, it will be helpful for workplaces that are having difficulty removing nitrogen.

• Journal of Korean Society on Water Environment
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• v.22 no.1
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• pp.83-90
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• 2006

Performance and operation of BAC in ozone-BAC advanced water treatment process were investigated using the pilot scale test plant built in D water purification plant. The performance was evaluated by the removal efficiencies of DOC, BDOC, ammonia nitrogen and THMs. The effect of EBCT on DOC removal was experimented for an effective operating condition, and the amount of attached biofilm was analyzed in various water temperatures and position of BAC. Two removal mechanisms, adsorption and biological decomposition by attached biofilm, were predominant to decrease the concentration of various contaminants. DOC was removed 40%, and the removal rate was decreased in winter time due to the lowered activity of attached biofilm. BDOC was effectively removed. THMs and ammonia nitrogen were mainly removed not in ozonation process but in BAC. Water temperature deeply influenced in removal efficiency of ammonia nitrogen. The amount of attached biofilm depended on water temperature and height of packed activated carbon column. Considering DOC removal efficiency and design EBCT of commercial BAC plant, the proper EBCT was 12.5 minutes.

• Journal of Environmental Science International
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• v.32 no.6
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• pp.465-475
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• 2023

In this study, we evaluated the treatment efficiency of livestock wastewater by altering the current density using boron-doped diamond (BDD) electrodes. As the current density was adjusted from 10 to 35 mA/cm2, the removal efficiency of organic matter increased from 22.2 to 71.5%. Similar to that of organic matter, the removal efficiency of color increased with increasing current density up to 85.7%, indicating a higher removal efficiency for color than that of organic matter. The removal efficiency of ammonia nitrogen increased from 14.6 to 53.3% as the current density increased, but it was lower than that of organic matter. In addition, the removal of organic matter, color, and ammonia nitrogen followed first-order reactions, according to the reaction rate analysis. The energy consumption ranged from 4.87 to 8.33 kWh/kg COD, and it was found that the organic matter removal efficiency was more efficient at high current densities. Based on various analyses, the optimal current density was 20 mA/cm2, and the corresponding energy consumption was 6.824 kWh/kg COD.

• Journal of Korean Society of Water and Wastewater
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• v.13 no.2
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• pp.34-40
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• 1999

Aerobic night-soil treatment effluent containing high concentration of ammonia nitrogen was treated to remove nitrogen using Bardenpho process with Methanol addition. The objective of this study was to investigate the feasibility of complete nitrogen removal at three different HRTs such as 6.25d, 5d, and 3.75d, respectively. At each HRT, the nitrogen removal efficiencies are 92%, 99% and 97% and the required amount of methanol are 3.05gMeOH/gN, 2.75gMeOH/gN, and 3.38gMeOH/gN, respectively. Specific nitrification rates are decreased proportional to HRT and are $0.022gNH_4^+-N/g\;MLVSS{\cdot}day$, $0.0332gNH_4^+-N/g\;MLVSS{\cdot}day$ and $0.051gNH_4^+-N/g\;MLVSS{\cdot}day$ and specific denitification rate are decreased proportional to HRT and are $0.0210g\;N/gMLVSS{\cdot}day$, $0.0330g\;N/gMLVSS{\cdot}day$ and $0.0525g\;N/gMLVSS{\cdot}day$, respectively.