Treatment of Nutrient-rich Municipal Wastewater Using Mixotrophic Strain Chlorella kessleri GXLB-9

Growing algae on wastewaters offers a promising way for effective N and P recycling as well as low-cost algal biofuel feedstock accumulation. In this study, a locally isolated microalgae strain Chlorella kessleri GXLB-9 (C. kessleri GXLB-9), was evaluated for growth and nutrient removal efficiency grown in nutrient-rich wastewater centrifuged from activated sludge (NWCAS). And 3-(3, 4-dichlorophenyl)-1, 1-dimethyl urea (DCMU), one chemical that could block microalgae-based photosynthetic pathway, was used to evaluate the growth mode (autotrophy, heterotrophy or mixotrophy) of C. kessleri GXLB-9. The results showed that C. kessleri GXLB-9 was a facultative heterotrophic strain and 7-day batch cultivation idicated that the maximal removal efficiencies for total nitrogen, total phosphorus, and chemical oxygen demand (COD) were over 59%, 81%, and 88%, respectively, with high growth rate (0.490 d-1) and high biomass productivity (269 mg L-1 d-1). In addition, the impact of light-dark cycle on algae growth and nutrient removal was minimal while pH has significant impact on both algae growth and nutrient removal efficiency

Indirect Contact Chamber with Dielectric Layers for Pulsed Electric Field Treatment of Microorganisms

Investigation of pulsed electric field (PEF) treatment of yeast at 20 kV/cm using chambers with BaTiO3 dielectric layers was conducted in this study. The sterile rate as well as concentrations of metallic ions and hydroxyl radicals were measured to assess the PEF performance. The results indicated that generation of metallic ions could be reduced by 90%. However, a much higher field strength would be required for satisfactory sterilization due to the Maxwell-Wagner field relaxation, and reactions between the dielectric barriers and liquid could also occur. It was also proven that the continuous presence of a sufficient electric field is the main factor that inactivates the microorganism

Numerical Simulation of Interaction between Plasma and Azithromycin Based on Molecular Dynamics

Growing attention has been paid to nonthermal plasma treatment technology and its effects on the degradation of organic matter, especially for antibiotics. However, the majority of the conducted research has focused on the experimental results. Rare attempts were made to analyze the reaction mechanism at the microscopic level. In this paper, molecular dynamics simulation and reactive forcefields were used to investigate the reaction mechanism of different plasma particle interactions with azithromycin molecules. The simulation results indicated that the degradation of azithromycin was caused by the destruction of C-H and C-C bonds, followed by the formation of C=C and C=O bonds when reacted with the active particles. It was also found that the ability of degrading azithromycin varied among the different types of active particles. The oxygen atoms had the strongest ability to decompose the azithromycin molecule, with 38.61% of the C-H bonds broken as compared with other oxygenated species. The findings from this computational simulation could provide theoretical support and guidance for subsequent practical experiments