• Journal of the Korea Organic Resources Recycling Association
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• v.21 no.3
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• pp.82-92
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• 2013

The Intermittent Aeration MBR systems have the advantage of controlling reaction time by changing aeration period and are one of economic BNR systems since these processes do not require MLSS recirculation that demands capital and operation costs. In this study, two intermittent aeration MBR systems were studied by computer simulation: an intermittent aeration MBR system that had both 1hr/1hr and 4hr/4hr aeration/unaeration periods at intermittent reactor and NEW INTERMITTENT-process that was an energy saving process and certified as a new process by Korean government. Since DO concentration reached only at 0.23mg/L at intermittent reactor when it was aerated, the Intermittent aeration MBR system having 1hr/1hr aeration/unaeration period showed simultaneous nitrification/denitrification and had the highest nitrogen and phosphorus removal efficiencies that were 57% and 55%, respectively. Since this study was based on the constant influent flow and characteristics, more studies are needed to define the operational characteristics of intermittent aeration MBR systems under dynamic influent conditions.

• Journal of Industrial Technology
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• v.23 no.A
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• pp.193-197
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• 2003

This bench-scale research investigated the aeration cycle(on/off) as the controlling factors for nitrogen and phosphorus removal in a 2-stage, intermittent aeration process. At this experiment, the aeration cycle time(air-on/air-off) was 30min/30min, 60min/60min, 90min/90min. Organic matter removal was observed more than 90% regardless of the aeration cycle and phosphorus removal was relatively high when the aeration cycle time was 60min/60min On the other hand. For all of the aeration cycle, TN removal was appeared less than 55%. This result was probably due to the limitation of the external substrate for heterotrophic nitrification and aerobic denitrification.

• Journal of the Korean GEO-environmental Society
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• v.4 no.3
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• pp.61-67
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• 2003

A new precess which consists of pre-dewatering device, post composting for solid phase and post sequencing batch reactor(SBR) for liquid phase was designed. Nitrogen in supernatants of dewatering device was removed by sequencing batch reactor. Experiments were carried out to investigate the SBR operation modes such as fill ratio, SRT, and operation cycle. The optimum fill ratio, SRT and aeration/non-aeration time were 1/12, 15days, and 2hr aeration / 1hr non aeraion, respectively. Methanol as an external carbon source increased denitrification when step feeding method was applied, not single feeding method.

• Journal of the Korean Magnetics Society
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• v.12 no.6
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• pp.206-211
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• 2002

We have constructed a new kind of magnetic motion capture sensor based on the pulse magnetic field method. 3-orthogonal magnetic pulse fields were generated in turns only one period of sinusoidal waveform using 3-orthogonal magnetic dipole coils, ring counter and analog multiplier. These pulse magnetic fields were measured with 3-orthogonal search coils, of which induced voltages by the x-, y-, and l-dipole sources using S/H amplifier at the time position of maximum induced voltage. Using the developed motion capture sensor, we can measure position of sensor with uncertainty of ${\pm}$0.5％ in the measuring range from ${\pm}$0.5 m to ${\pm}$1.5 m.

• Journal of Animal Environmental Science
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• v.18 no.3
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• pp.207-220
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• 2012

There are around 7,500 manure tanks to treat the manures from pigs in Korea. In the tank, there are too much sediments deposited on the base and wall, which causes low efficiency of stock capacity and manure fermentation. In order to minimize sediments and to ferment manure effectively, we developed a 2-fluid jet mixer for mixing sediments in liquid livestock manure tank. For developing the prototype, we tested a factorial experimental system with various nozzles, and simulated CFD models with two kinds of nozzle arrangement. From the results of factorial experiment and CFD simulation, we concluded the dia. ratio of primary : secondary nozzle should be 1:2 and the nozzles should be arranged at the same distances toward to the circumferential direction. With this results, we manufactured a 2-fluid jet mixer which is consists of four 2-phase nozzles, centrifugal slurry pump and root's type air blower. And, we carried out the performance test of the prototype in the round shaped liquid manure tank in the farm. The performance test results showed that the uniformity of TS (Total Solid) and VS (Volatile Solid) was raised from 21.3 g/L, 13.3 g/L In steady state to TS and VS to 23.0 g/L, 14.1 g/L in the mixing operation. Therefore, we could conclude that the prototype of 2-fluid mixer could make the solid material which could be sediments in the tank not to be deposited in the tank and to be contacted to air bubbles which could enhance the efficiency of the fermentation of livestock manure.