• Progress in Superconductivity and Cryogenics
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• v.25 no.3
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• pp.7-12
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• 2023

Isolation of pollutant-degrading bacteria is important in bioaugmentation, one of the methods for biological degradation of environmental contaminants. We focused on the magnetic activated sludge (MAS) process as a culture method that efficiently concentrates degrading bacteria, and cultured activated sludge with 1,4-dioxane as a model pollutant. After 860 days of operation, MLVSS, which indicates the amount of sludge, increased from 390 mg/L to 10,000 mg/L, and the removal rate of organic matter including 1,4-dioxane, tetrahydrofuran, and glucose in the artificial wastewater reached up to 97%. Based on these results, the MAS process was successfully used to acclimate activated sludge with 1,4-dioxane. Bacterial flora analysis in the MAS showed that bacteria of the genus Pseudonocardia, already reported as 1,4-dioxane degrading bacteria, play an important role in the degradation of this pollutant. The MAS process is a suitable culture method for acclimation of environmental pollutants, and the findings indicate that it can be used as an enrichment unit for pollutant-degrading bacteria.

• Progress in Superconductivity and Cryogenics
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• v.23 no.3
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• pp.32-36
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• 2021

Milking parlor wastewater contains not only high concentrations of organic compounds, but often animal antibiotics. To discharge the antibiotics to public water area cause problem of antibiotics resistant bacteria. Magnetic separation was applied into improvement of milking parlor wastewater treatment process. A new process, composed of a magnetic activated sludge (MAS) process and a contact oxidation (CO) process, was proposed in this study. This process was evaluated by the simulated milking parlor wastewater (4500 mg/L COD_Cr and 10 mg/L tetracycline) using a bench scale experimental setup. As a result, the process was able to removed 97% COD_Cr as well as 94% tetracycline. The MLVSS (mixed liquor volatile suspended solids) concentration of MAS was maintained at 12000 mg/L without excess sludge drawing. This process was considered to be useful as treatment process for milking parlor wastewater in which waste-milk including antibiotics is often discharged.

• 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.

• Journal of Korean Society of Water Science and Technology
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• v.26 no.6
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• pp.117-124
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• 2018

For the effective removal of phosphorus in water, a novel type of composite was prepared by combining Poly Alumiun Chloride, widely used in sewage/wastewater treatment plants, and Humic Acid particles, which are known to have phosphorus removal ability, with CI. The surface of the ferromagnetic CI particles was oxidized and activated, and then PAC and HA were synthesized to finally produce CIPAC and CIHA. CIPAC and CIHA prepared by this study showed similar results to the phosphorus removal efficiencies of PAC and HA coagulants. The novel composite has a larger weight than the conventional coagulant, and the coagulated sludge precipitates rapidly. The sludge could be easily separated in a short time if the external magnetic field was given by the ferromagnetic force of CIPAC and CIHA prepared with CI as support. Therefore, it can be concluded that if phosphorus removal is carried out using CIPAC and CIHA prepared through this study with external magnetic field, the sedimentation rate will be much faster than that of conventional coagulant. Thus it is possible to obtain a high economic benefit in the sludge recovery part.