• Journal of Environmental Science International
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• v.25 no.9
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• pp.1233-1239
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• 2016

This study aimed to evaluate changes in the TN and TP removal efficiencies, depending on whether or not a settling process is applied, in a sequencing batch reactor (SBR) process with a membrane bioreactor (MBR). Nutrient removal was considered in terms of developing an advanced water treatment system for ships in accordance with water quality standards set forth by 227(64). For these purposes, the TN and TP concentrations in the inflow and outflow water were measured to calculate the TN and TP removal efficiencies, depending on whether or not a settling process was used. Water discharged from a bathroom, which was constructed for the experiment, was used as the raw water. The experiment that included a settling process was conducted twice, and the operating conditions were: aeration for 90 min, settling for 30 min, agitation for 15 min, and settling for 15 min for one experiment; and aeration for 150 min, settling for 45 min, agitation for 15 min, and settling for 15 min in the other. Operating conditions for the experiment that did not include a settling process were: aeration for 180 min and agitation for 60 min. The concentration of the mixed liquor suspended solids (MLSS) in the reactor was 3,500 mg/L, while the aeration rate was 121 L/min and the water production rate was 1.5 L/min. For the two experiments where a settling process was applied, the average TN removal efficiencies were 44.39% and 41.05%, and the average TP removal efficiencies were 47.85% and 46.04%. For the experiment in which a settling process was not applied, the average TN removal efficiency was 65.51%, and the average TP removal efficiency was 52.51%. Although the final nutrient levels did not satisfy the water quality standards of MEPC 227(64), the TN and TP removal efficiencies were higher when a settling process was not applied.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.2
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• pp.13-18
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• 2019

Sewage sludge treatment is increasing every year due to improvement of living and urbanization. However, interest in anaerobic digestion which is one of the recycling technology. There is anaerobic digestion of increasing due to limitations of ocean dumping and final disposal. But, the limit of anaerobic digestion efficiency due to the advanced treatment of sewage has been limited, and studies for solubilization technology have been actively conducted. Therefore, in this study, we aimed to investigate the variation of generation of scum and the solubilization efficiency in the application of pre-treatment of ozone reaction and the change of properties of digested sludge with wet milling. There are results of VS/TS increased by 4.4% and $SCOD_{cr}/TCOD_{cr}$ increased by 9.4% by wet milling alone. In addition, the increase of the specific surface area due to which the reduction of the particle size of the solid content of the sludge in the ozone reaction caused by wet milling decreased the generation rate of scum at 14.3% and increased VS/TS at 2.1%, compared with the ozone reaction alone. From these results, it is expected that the application of wet milling can be increased the contact efficiency with solids in the sludge during ozone reaction with suppress scum and increase the efficiency of the subsequent process in anaerobic digestion.

• Journal of Advanced Marine Engineering and Technology
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• v.26 no.3
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• pp.375-381
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• 2002

Measuring of the dissolved oxygen is widely used for the environmental control of natural waters, sewage waste treatment, medical and biochemical studies, soil husbandry, food and drug process control, and prevention of corrosion in boilers. Especially, a power plants need special management for preventing accidents from corrosion, therefore, it is essential to measure the concentration of dissolved oxygen in real-time. In this paper we present a method of measuring dissolved oxygen very accurately up to pub units. This method, called polarograph method, is based on the measures of the electric current generated by the oxidation process in cathode and de-oxidation process in anode, assuming that the amount of the current is proportional to the density of dissolved oxygen.

• Journal of Korean Society on Water Environment
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• v.23 no.5
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• pp.781-788
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• 2007

The Carbon source to enhance the denitrification is essential matter in the advanced sewage treatment. For the high level of nutrient removal, external carbons such as ethanol, methanol, volatile fatty acids and so on should be needed. In this study, the methods to increase the sludge solubilization and acidification rate were compared with waste activated sludges and food waste leachate. Ultrasonication and acids were used for the pretreatment of organic particles in sludges. As a results, the optimal temperature and HRT were $60^{\circ}C$ and 5 days, respectively. HAc, HPr, HBr, and other VFAs for acid fermentations reduced up to 22, 16, 14, and 48% with HRT reduction. For the increase of solubilization, 28% of solids destruction rate was shown at 0.3 watts/mL.

• Journal of Korean Society on Water Environment
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• v.25 no.6
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• pp.872-878
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• 2009

Advanced Phase Isolation Ditch (APID) process was studied to develop economic retrofitting technology, for the plants where retrofitting of common activated sludge process is required. In this study, to develop and apply the modified intermittently aeration mode as process control conditions for treating municipal wastewater, a demonstration plant was installed and operated in the existing sewage treatment plant of P city. During this study, the average effluent $BOD_5$, SS, T-N, and T-P concentrations were 6.3, 4.5, 10.0, and 1.3 mg/L. The modified mode decreased the nitrification capability more than the conventional mode in the application period. Nitrate in the anaerobic condition can have a negative effect on biological phosphorus removal. In the decreasing nitrate levels, the modified mode increased the biological ability of removal phosphorus more than the conventional mode in this study. Therefore, newly developed APID process with modified intermittent aeration mode can be one of the useful processes for stable organic matter and nutrients removal.

• Clean Technology
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• v.13 no.2
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• pp.87-98
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• 2007

As the interest in environmental problems increased, the guideline of effluent qualities becomes strict and the amount of sludge produced from the wastewater treatment facilities steeply increased. The revised Korean acts prohibit the direct reclamation of the sludge exhausted in sewage treatment works from 2003, and the ocean dump of sludge will be also prohibited from 2012. Therefore, the sludge must be recycled, incinerated or composted. To properly perform the utilization and disposal operations, the establishment of well-defined procedures for the characterization of sludge by physical, chemical and biological method and setting up of guidelines for different treatment and disposal routes has become necessary. However, there have not been such standardized methods for sludge characterization in Korea. This review analyzes the present status of establishment and problems of sludge characterization method of Korea. Finally, it was proposed total 15 items of standardized characterization methods suitable to our country for proper sludge recycling and disposal, which was based on the more systematic standard methods of Germany (DIN 38414) and those of advanced nations.

• Journal of the Korean Applied Science and Technology
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• v.31 no.4
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• pp.669-678
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• 2014

The amount of waste water generated from the domestic sources is consistently increasing in proportion to economic growth, and the conventional activated sludge process is widely being used for general waste water treatment. But the ministry of environment becomes stringthent treatment standards of N and P (less than 20mg/L of N, 2mg/L of P) to prevent the eutrophication of lake water, and therefore highly advanced treatment technology is required not only in the existing treatment plants where the activated sludge process is being used, but also in newly constructed treatment plants for the treatment of N and P. This study is aimed at highly operating the engineering technology method was developed by domestic to eliminate N and P at the same time. Experiments were conducted in the treatment plant located in Yong In city. The bioreactor was started from the principal equipment for the elimination of N and P and the elimination of organic compounds. It consists of an internal recycle piping from the end of the aerobic tank to the anoxic tank and external recycle piping from the final settling basin to the denitrification tank. By experiment of 4 types separate inflow of waste water to the denitrification tank and the anaerobic tank, and changes in staying time at the anoxic tank and the aerobic tank, the elimination of organic compounds in each type and the relationship in the efficiency between the elimination of N and P were researched.

• Journal of the Korea Organic Resources Recycling Association
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• v.32 no.2
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• pp.15-25
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• 2024

In this study, the regeneration effect of pressurized water and ultrasonic cleaning was investigated for contaminated filter cloth from the sewage sludge filter press process. For this purpose, contaminated filter cloth was collected from a 3-ton sewage sludge hydrothermal carbon treatment filter press. First, the contamination characteristics were analyzed. According to the location of the filter cloth, air permeability and unit mass were measured, and compared with the values of a new filter cloth. Next, the results were mapped over the entire area to evaluate the contamination characteristics. Finally, pressure cleaning at 3 bar and ultrasound at frequencies of 34, 76, 120, and 168 kHz were performed on the contaminated filter cloth. In addition, the cleaning efficiency was evaluated by 3 levels of contamination degree. As a result, pore contamination occurred mainly at the bottom and both sides of the filter cloth, where the filter material was continuously injected and compressed. Surface contamination appeared evenly over the entire area. As a result of washing, air permeability increased by 1.3-3.1%p and contaminant removal was by 2.7-4.4% under pressure. In ultrasonic cleaning, air permeability increased by 12.5-61.5%p and contaminants were removed by 2.7-29.2%. In ultrasonic cleaning the lower the frequency, the higher air permeability and contaminant removal rate. Also, The higher pore contamination level, the better the air permeability improvement and contaminant removal.

• Journal of environmental and Sanitary engineering
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• v.24 no.1
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• pp.13-24
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• 2009

This study was performed to determine the effect of the influent flow distribution ratio and hydraulic retention time(HRT) on removal of organic matter, nitrogen and phosphorus when domestic sewage was treated by the advanced step aeration(ASA) process. Results of the experiment for the determination of the optimum influent flow distribution ratio between the anaerobic reactor and the anoxic reactor showed BOD removal efficiencies of above 92.0% at all influent flow distribution ratios from 9:1 to 4:6. The highest T-N removal efficiency was 82.6% at the influent flow distribution ratio of 6:4. On the other hand, the highest T-P removal efficiency was 67.8% at the influent flow distribution ratio of 9:1. Considering both the T-N and T-P removal efficiencies, the influent distribution ratio of 6:4 was considered the optimum. Results of the experiment for the determination of the optimum HRT at the optimum influent flow distribution ratio of 6:4 revealed BOD removal efficiencies better than 92.7% at all HRTs from 12hr down to 6hr. The highest T-N and T-P removal efficiency were 82.6% and 59.5%, respectively both at the HRT of 8hr. In conclusion, the optimum influent flow distribution ratio and HRT for treatment of domestic sewage by the ASA process were determined to be 6:4 and 8hr, respectively.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1174-1178
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• 2007

본 연구는 다양한 공법으로 설치 운영되고 있는 고도처리시설에 대한 처리효율 및 운영현황을 조사하여 고도처리공법 선정시 활용할 수 있는 기초자료를 제공하고, 각 공법별 현장적용 및 운영상 문제점을 파악하여 하수처리시설 운영의 효율성을 도모하기 위한 목적으로 실시하였다. 6개월 이상 운영 중인 하수종말처리시설 145개소를 대상으로 일반적 현황을 분석하고 실제 현장조사는 고도처리시설 37개소의 현장조사표를 중심으로 실시하였다. 고도처리 공법은 $A_2O$계열, SBR계열이 대부분을 차지하였으며 대규모처리장은 $A_2O$계열, 소규모처리장은 SBR계열이 주로 적용되었으며 대규모 하수처리시설일수록 유입수질의 농도 및 처리효율이 높고 톤당 시설설치비용과 유지관리비용이 적었다. 현장조사 결과, 첫째, 하수처리시설의 유입문제로 시설용량대비 하수유입량이 초과되거나 50%미만인 시설이 10개소로 조사되었다. 이에 따라 하수관거의 조속한 정비 및 인구감소에 따른 대책수립, 효율적인 운영을 위한 하수처리시설 증설 및 계열 축소운전이 필요하였다. 둘째, 각 처리공법별로 몇몇 문제점이 있어 공법사의 문제점 보완, 운영기술전수 및 원활한 A/S가 필요한 것으로 나타났다. 셋째, 운영관리자가 수시로 현상을 파악하고 주의하여 운전해야 하는 것으로 나타났다.