• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.5
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• pp.398-404
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• 1984

This study was attempted to investigate variation of the bacterial flora in waste water treatment of fish meat paste plant by batch and continuous culture. The results of the experiment are as follows : 1. The removal rate of BOD in waste water treatment by activated sludge of continuous culture was above $90\%$. 2. In the process of nitric acidification of protein waste water, $NH_4-N\;and\;NO_2-N$ increased untill the lapse of 48 hours from culture, but $NO_3-N$ showed little change. 3. In activated sludge obtained from acclimation by batch culture for 10 days, bacteria good in capacity of nitric acidification were not appeared. 4. Among 120 strains of isolated bacteria, the most predominantly appeared bacterial flora were Enterobacteriaceae ($28\%$) and Pseudomonas spp. ($25\%$), In the latter term of aeration during which ammonia originates in abundance, Pseudomonas spp. was decreased but Enterobarteriaceae was increased. 5. Fifty percent of the isolated strains were able to grow in $0\%,\;3\%$ NaCl and $75\%$ artificial sea water, Therefore, it is suggested that sea water can be used as dilution water instead of tap water during the treatment of waste water.

• Korean Journal of Environmental Biology
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• v.40 no.3
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• pp.267-274
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• 2022

Excess nitrogen (N) flowing from livestock manure to water systems poses a serious threat to the natural environment. Thus, livestock wastewater management has recently drawn attention to this related field. This study first attempted to obtain the optimal conditions for the further volatilization of NH₃ gas generated from pig wastewater by adjusting the amount of injected magnesia (MgO). At 0.8 wt.% of MgO (by pig wastewater weight), the volatility rate of NH₃ increased to 75.5% after a day of aeration compared to untreated samples (pig wastewater itself). This phenomenon was attributed to increases in the pH of pig wastewater as MgO dissolved in it, increasing the volatilization efficiency of NH₃. The initial pH of pig wastewater was 8.4, and the pH was 9.2 when MgO was added up to 0.8 wt.%. Second, the residual ammonia nitrogen (NH₄⁺-N) in pig wastewater was removed by precipitation in the form of struvite (NH₄MgPO₄·6H₂O) by adjusting the pH after adding MgO and H₃PO₄. Struvite produced in the pig wastewater was identified by field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) analysis. White precipitates began to form at pH 6, and the higher the pH, the lower the concentration of NH₄⁺-N in pig wastewater. Of the total 86.1% of NH₄⁺-N removed, 62.4% was achieved at pH 6, which was the highest removal rate. Furthermore, how struvite changes with pH was investigated. Under conditions of pH 11 or higher, the synthesized struvite was completely decomposed. The yield of struvite in the precipitate was determined to be between 68% and 84% through a variety of analyses.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.4
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• pp.414-419
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• 2005

This study was performed to compare the treatment efficiencies of two media, newly developed Bio-rock and conventional gravel, in soil clothing contact oxidation process. The composition of synthetic wastewater were $COD_{Cr}$ $150{\sim}370\;mg/L$, $BOD_5$ $150{\sim}270\;mg/L$, T-N $20{\sim}60\;mg/L$, T-P $5{\sim}25\;mg/L$, pH 7 and 2 mL/L of trace element solution. The experiment using two reactors was comparatively conducted for the flow rate of 40 L/d for 13 months, respectively. Initially Bio-rock reactor was increased to pH 12 due to $Ca(OH)_2$ with hydration of cement, but gravel reactor was dropped to pH 4 due to the degradation of organic material and nitrification. This significant pH variation deteriorated the growth and activity of microorganism. But the high pH of Bio-rock seems favorite to ammonia stripping and precipitation of phosphate. Such pH variation of Bio-rock and gravel reactors were finally stabilized to pH 8 and pH 6, respectively. The removal efficiencies of organic compounds from Bio-rock reactor were 96% of $COD_{Cr}$, 98% of $BOD_5$, 80% of T-N and 85% of T-P which stably coping against variation of influent concentration. But those of gravel reactor were 96% of $COD_{Cr}$, 96% of $BOD_5$, 42% of T-N and 40% of T-P, respectively. The Bio-rock was 2 times higher than T-N and T-P in treatment efficiency. And electron-microscopic examination showed that Bio-rock was more favorable to microbial adherence than gravel. The microbial populations were $5.2{\times}10^6\;CFU/mL$ of Bio-rock reactor compared to $2.6{\times}10^6\;CFU/mL$ in gravel reactor. In result Bio-rock was favor to microbial adherence and high treatment efficiency in spite of variation of influent concentration which had the advantages in saving running time and reducing site requirement.