• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8665-8672
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• 2015

In this study, to investigate the feasibility of malodorous substance and organic matter removal by digest sludge in sewage treatment plants, ammonia, methyl mercaptan(MMC), and hydrogen sulfide($H_2S$) in a reactor submerged with BIO-CLOD(BIO-CLOD) and a reactor not submerged with BIO-CLOD(Non BIO-CLOD) were measured at 24 hours, 48 hours, and 72 hours after the submergence of BIO-CLOD. Whereas the reactor in which BIO-CLOD was submerged showed an ammonia removal rate of 48% and high $H_2S$ and MMC removal rates exceeding 98% in 24 hours, the reactor in which BIO-CLOD was not submerged showed an ammonia removal rate of 45%, an $H_2S$ removal rate of 71%, and an MMC removal rate of 84% in 24 hours indicating the possibility of removal of malodor using BIO-CLOD. A nitrification was shown in which ammonia concentrations decreased over time while nitrate nitrogen concentrations increased and sulfur based malodor components were oxidation decomposed indicating that BIO-CLOD had effects to increase sulfate concentrations in the solution and that sulfate concentration increases and atmospheric $H_2S$ removal rates were correlated with each other. With regard to decreases in organic matter in reactor effluents, BIO-CLOD did not affect in a short period of time and when reactors were operated with HRT 12 hours and HRT 24 hours, HRT 12 hours was considered desirable in terms of economy.

• Applied Chemistry for Engineering
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• v.34 no.5
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• pp.541-547
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• 2023

The effect of temperature and influent alkalinity/ammonia (K/A) ratio on the start-up of the partial nitrification (PN) process for an activated sludge-based domestic wastewater treatment was studied. Two different sequence batch reactors (SBR) were operated at 26 ℃ and 32 ℃. The relationship between temperature and the concentration of free ammonia (FA) and free acid nitrite (FNA) was investigated. A stable PN process was achieved in the 32 ℃ reactor when the influent ammonium concentration was lower than 150 mg-N/L. In contrast, the PN process in the 26 ℃ reactor had a higher nitrite accumulation rate (NAR) and ammonium removal efficiency (ARE) when the influent ammonia concentration was increased to more than 150 mg-N/L. Then three different ranges of the K/A ratio were applied to an SBR reactor. In the K/A range of 2.48~1.65, the SBR reactor achieved the highest NAR ratio (75.78%). This ratio helps to achieve the appropriate level of alkalinity to maintain a stable pH and provide a sufficient amount of inorganic carbon source for the activity of microorganisms. At the same time, FA and FNA values also reached the threshold to inhibit nitrite-oxidizing bacteria (NOB) without a significant effect on ammonia-oxidizing bacteria (AOB). Results showed that the control of temperature and K/A ratio during the start-up period may be important in establishing a stable and steady PN process for the treatment of domestic wastewater.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.1
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• pp.49-57
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• 2009

This research examined the effect of ammonia nitrogen loading rate(NVLR) on the anaerobic digestion of slurry-typed swine wastewater. The anaerobic reactor was used an upflow anaerobic sludge blanket (UASB) process. This UASB reactor was operated at a NVLR of $0.02{\sim}0.96kg{NH_4}^+-N/m^3/day$. The methane content showed the range of 73.3~77.9% during the steady state period. Free ammonia(FA) concentration increased over inhibition level as pH increase from 7.3 to 8.2. However, in consideration of methane content, methane producing bacteria (MPB) inhibition by FA and total ammonia(TA) was not observed. A stepwise increase of the NVLR resulted in a deterioration in the COD removal rate in UASB reactor. The COD removal rate were 60% for NVLR up to $0.55kg{NH_4}^+-N/m^3/day$. As the NVLR increased from 0.09 to $0.96kg{NH_4}^+-N/m^3/day$, the biogas production rate varied from 3.71 to 9.14L/d and the methane conversion rate of the COD varied from 0.32 to $0.20m^3CH_4/kg$ COD removed. Consequently, in considerations of FA concentration, COD removal rate, and $CH_4$ production rate, the UASB reactor must be operated to lower than $0.40kg{NH_4}^+-N/m^3/day$ of NVLR.

• Journal of Aquaculture
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• v.16 no.3
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• pp.142-150
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• 2003

Performance of a biological filter, the rotating biological contactor (RBC), is affected by rotational speed and hydraulic residence time (HRT). A RBC with a disc diameter of 62 cm, total surface area of 48.28 $m^2$, volume of 0.34 ㎥, and submergence ratio of 35.4% was tested for the combinations of five rotational speeds (1, 2, 3, 4 & 5 rpm) and three HRT (0.5, 1.0 & 2.0 hr) to find out the maximum removal efficiencies of total ammonia nitrogen (TAN) and nitrite nitrogen of a simulated recirculating aquaculture system. Ammonia loading rate in the system was 25 g of TAN/ ㎥. day. Removal efficiencies were checked when TAN concentrations in the system stabilized for 3 days in each treatment. The concentration of TAN in the system decreased with increasing rotational speed of the RBC up to 4 rpm in all HRT (P<0.05). At the rotational speed of 5 rpm, the efficiencies decreased in all HRT (P<0.05). When the rotational speeds were 1, 2, 3, 4, and 5 rpm, TAN concentrations in the system were 1.35, 0.94, 0.69, 0.66, and 0.76 mg/L at the 0.5 hr HRT, 2.86, 1.18, 0.96, 0.87, and 1.11 mg/L at the 1.0 hr HRT, and 5.30, 2.44, 1.99, 1.77, and 2.01 mg/L at the 2.0 hr HRT, respectively. The TAN removal efficiencies of the RBC at the rotational speeds of 1, 2, 3, 4, and 5 rpm were 32.9, 49.5, 65.1, 72.9, and 62.9% in 0.5 hr HRT,33.1, 74.1, 87.1, 95.8, and 78.5% in 1.0 hr HRT, and 35.5, 76.7, 89.6, 97.0, and 85.5% in 2.0 hr HRT, respectively. TAN removal efficiency of RBC per pass increased with increasing HRT. However, TAN concentration in the system also increased. The best operating condition among the treatments was obtained at the treatment of 0.5 hr HRT and 4 rpm (P<0.05). The TAN concentration was 0.66 mg/L. Concentrations of nitrite nitrogen (NO$_2$$^{[-10]}$ -N) in the system decreased with increasing rotational speed in all HRT while that in the system increased with increasing HRT in all rotational speeds. The ranges of NO$_2$$^{[-10]}$ -N concentrations at HRT of 0.5, 1.0, and 2.0 hr in the system were 0.26~0.32, 0.31~0.56, and 0.43~l.45 mg/L, respectively. The ranges of daily removal rates of TAN in this system were 20.03~23.0 g TAN/㎥ㆍday and those of nitrite nitrogen were 19.65~30.25 g NO$_2$$^{[-10]}$ -N/㎥ㆍday.

• Environmental Engineering Research
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• v.22 no.1
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• pp.12-18
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• 2017

Struvite precipitation has been proven to be an effective method in removing and recovering ammonia nitrogen (N) and phosphate phosphorus (P) from wastewater. In this study, effects of pH, molar ratios and pre-treatment of effluent of anaerobically digested swine wastewater were investigated to improve struvite crystallization. The magnesium : ammonium : phosphate ratio of 1.2 : 1.0 : 1.0 was found to be optimal, yet the molar ratio in the wastewater was 1 : 74.9 : 1.8. From the analysis, the optimum pH was between 8.0 and 9.0 for maximal phosphate P release and from 8.0 to 10.0 for maximal ammonia N and phosphate P removal from real wastewater. Analysis from Visual MINTEQ predicted the pH range of 7-11 for ammonia N and phosphate P removal and recovery as struvite. For pre-treatment, microwave pre-treatment was ineffective for phosphate P release but ultrasound pre-treatment showed up to 77.4% phosphate P release at 1,000 kJ/L of energy dose. Precipitates analysis showed that phosphorus and magnesium in the collected precipitate had almost same values as theoretical values, but the ammonia content was less than the theoretical value.

• Progress in Superconductivity and Cryogenics
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• v.23 no.3
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• pp.20-25
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• 2021

Milking parlor wastewater contains high concentration suspended solid (SS), nitrogen, and/or phosphate as well as organic compounds. A new biological wastewater process by magnetic separation, magnetic activated sludge (MAS) process, was applied to milking parlor wastewater treatment process. A three step wastewater treatment process of coagulation sedimentation / ammonia stripping (C/S), magnetic activated sludge process and contact oxidation (CO) was proposed for removal of these pollutants. First step, C/S process recovered 96% TN and 96% PO₄^3--P as resource for fertilizer from the wastewater. 81% biochemical oxygen demand (BOD) in wastewater was removed after MAS process. As a results, all pollutant concentrations satisfied Japanese effluent standards. Most of residual BOD and SS were removed by the CO process. It was estimated that the proposed process could reduce the process space to 1/7.

• Korean Journal of Microbiology
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• v.44 no.1
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• pp.29-36
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• 2008

Nitrogen is one of the major pollutants that should be removed by wastewater treatment systems. Biological nitrogen removal (BNR) is a key technology in advanced wastewater treatment systems operated by bacterial populations. Nitrification is the first step of microbiological processes in BNR system. Ammonia is oxidized to nitrite by ammonia-oxidizing bacteria (AOB) and then nitrite is subsequently oxidized to nitrate by nitrite-oxidizing bacteria (NOB). The diversity of NOB in nitrification reactors of 3 BNR systems, Edited biological aerated filter system, Nutrient removal laboratory system, and the Rumination type sequencing batch reactor system, was investigated by terminal restriction fragment length polymorphism (T-RFLP) analysis of 16S rRNA genes. Cluster analysis of T-RF profiles showed that communities of Nitrobacter group in each system were different depending upon the process of systems. However, the clusters of Nitrospira group were divided by the habitat of aqueous and solid samples.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.5
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• pp.868-873
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• 1997

Nitrifier consortium entrapped in Ca and Ba-alginate beads were packed into two reactors and studied for removing ammonia-nitrogen in aquaculture system. The ammonia-nitrogen concentration of the influent was continually kept about 2 ppm. At the hydraulic residence time of 0.6 hours, ammonia-nitrogen removal amount of two reactors was about 52.6 and 51.0 g $NH_3-N/m^3/day$, respectively. The ability of adjusting to an impulsive leading which was happened according to variations of HRT was better at Ba-alginate reactor, but its discrepancy was not so large. At the respect of removing ammonium-nitrogen, two reactors showed the similar ability of treating recirculating water.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.4
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• pp.579-589
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• 2012

To reduce extensive energy costs of the internal recycling for the purpose of denitrification in the advanced wastewater treatment, a post-treatment process using an electro-coagulation to treat nitrate in the secondary effluents is evaluated in this study. Removals of phosphorus and organics in the secondary effluents by the electro-coagulation were also evaluated to propose an alternative advanced wastewatert treatment process. A series of experiments of the electro-coagulation were carried out with the following 4 different samples: synthetic solution containing nitrate only, synthetic solution containing nitrate as well as phosphorus, secondary effluents from activated sludge cultivated in laboratory, and secondary effluents from real wastewater treatment plants. Removals of nitrate and phosphorus in the synthetic solution were 30 and 97 % respectively, which verified the feasibility of the process. Removals of nitrate, phosphorus and COD in the secondary effluents from the cultivated sludge in laboratory were 49, 90 and 19 % respectively. Removal efficiency of the total nitrogen, nitrrate, phosphorus and COD in the secondary effluent from real wastewater treatment plant were 50, 61, 98 and 80 % respectively. The removal of the total nitrogen was less than the nitrate as expected, which is due to the formation of ammonia nitrogen in the cathode. But the proposed scheme could be an energy saving and alternative process for the advanced wastewater treatment if further studies for the process optimization are carried out.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.3
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• pp.307-312
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• 2011

The potential of algal-bacterial culture was investigated for advanced treatment of animal wastewater. Fed-batch experiments were carried out to examine treatability of nitrogen and phosphorus in different microbial consortium: Chlorella vulgaris, activated sludge, three microalgae strains (Scenedesmus, Microcystis, Chlorella) and Bacillus consortium, and three microalgae strains and sludge consortium. Single culture of C. vugaris showed the better efficiency for nitrogen removal but was not good at organic matter and phosphorus removal compared with activated sludge. Three microalgae and Bacillus consortium was best culture among the culture and consortium for pollutants removal tested in this experiment. Effect of $CO_2$ addition was studied by using three microalgae and Bacillus consortium. $CO_2$ addition enhanced T-P removal efficiency up to 60%. However, removal efficiencies of T-N and ammonia nitrogen reduced on the contrary.