• Journal of Applied Biological Chemistry
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• v.66
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• pp.394-403
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• 2023

In the pursuit of sustainable and environmentally-friendly agricultural practices, we conducted an extensive study on the rhizosphere bacteria inhabiting soils that have been devoid of chemical fertilizers for an extended period exceeding 40 years. Through this investigation, we isolated a total of 80 species of plant growth-promoting rhizosphere bacteria and assessed their potential to enhance plant growth. Among these isolates, Burkholderia cepacia CD2 displayed remarkable plant growth-promoting activity, making it an optimal candidate for further analysis. Burkholderia cepacia CD2 exhibited a range of beneficial characteristics conducive to plant growth, including phosphate solubilization, siderophore production, denitrification, nitrate utilization, and urease activity. These attributes are well-known to positively influence the growth and development of plants. To validate the taxonomic classification of the strain, 16S rRNA gene sequencing confirmed its placement within the Burkholderia genus, providing further insights into its phylogenetic relationship. To delve deeper into the potential mechanisms underlying its plant growth-promoting properties, we sought to confirm the presence of specific genes associated with plant growth promotion in CD2. To achieve this, whole genome sequencing (WGS) was performed by Plasmidsaurus Inc. (USA) utilizing Oxford Nanopore technology (Abingdon, UK). The WGS analysis of the genome of CD2 revealed the existence of a subsystem function, which is thought to be a pivotal factor contributing to improved plant growth. Based on these findings, it can be concluded that Burkholderia cepacia CD2 has the potential to serve as a microbial fertilizer, offering a sustainable alternative to chemical fertilizers.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.1
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• pp.42-47
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• 2006

The biological nutrient treatment is formed with repetition and rearrangement of anaerobic, anoxic and oxic tank. In this case, VFAs is generated in the anaerobic tank and the anoxic tank. The VFAs is an important factor for removal of nitrogen and phosphate and SVI. So, in this study I investigated to find a relationship among the generation rate of the VFAs according to the change of F/M ratio and the characteristic which can eliminate organic matter and nitrogen according to the change of residual concentration of the VFAs and the efficiency of the process and also SVI in wastewater treatment. $A^2/O$ process was used for wastewater treatment. F/M ratio was under the control of the change of MLSS concentration. When the F/M ratio was changed from 0.16 to 0.08 kg-BOD/kg-MLSS/day, the VFAs's production volume increased based on the reduction of F/M ratio in batch reaction. And the residual concentration of the VFAs decreased at first and then increased later. SVI and SS were high when F/M ratio was $0.16kg/kg{\cdot}d$ and showed stable status when F/M ratio decreased $0.11{\sim}0.13kg/kg{\cdot}d$. However, SVI and SS continuously increased with decrease of F/M ratio and were high at $0.08kg/kg{\cdot}d$. In the result of comparison between residual concentration of the VFAs and denitrification rate in anoxic tank, the less residual volume of the VFAs was in anoxic tank, the higher denitrification ratio became. The optimal residual-concentration of the VFAs considering SVI and removal efficiency of nitrogenwas $1.4{\sim}2.2mg/L$. At that time F/M ratio was $0.11{\sim}0.13$ kg-BOD/kg-MLSS/day.

• Clean Technology
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• v.28 no.1
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• pp.63-78
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• 2022

Electronics industrial wastewater treatment facilities release organic wastewaters containing high concentrations of organic pollutants and more than 20 toxic non-biodegradable pollutants. One of the major challenges of the fourth industrial revolution era for the electronics industry is how to treat electronics industrial wastewater efficiently. Therefore, it is necessary to develop an electronics industrial wastewater modeling technique that can evaluate the removal efficiency of organic pollutants, such as chemical oxygen demand (COD), total nitrogen (TN), total phosphorous (TP), and tetramethylammonium hydroxide (TMAH), by digital twinning an electronics industrial organic wastewater treatment facility in a cyber physical system (CPS). In this study, an electronics industrial wastewater activated sludge model (e-ASM) was developed based on the theoretical reaction rates for the removal mechanisms of electronics industrial wastewater considering the growth and decay of micro-organisms. The developed e-ASM can model complex biological removal mechanisms, such as the inhibition of nitrification micro-organisms by non-biodegradable organic pollutants including TMAH, as well as the oxidation, nitrification, and denitrification processes. The proposed e-ASM can be implemented as a Water Digital Twin for real electronics industrial wastewater treatment systems and be utilized for process modeling, effluent quality prediction, process selection, and design efficiency across varying influent characteristics on a CPS.