Efficiency And Mechanism Of Algal System For Simultaneous Desulfurization And Denitrification Coupled With Antibiotics Removal In Wastewater

Pharmaceutical Wastewater is a kind of organic industrial wastewater contained with high concentration of sulfur and nitrogen.The current development of autotrophic-heterotrophic denitrification joint total sulfur removal of carbon and nitrogen oxide strengthen micro technology has been successfully synchronized desulfurization and denitrification of wastewater to improve performance.But the mechanical aeration energy consumption and carbon dioxide production cannot meet the concept of direct emissions"energy balance"and"carbon reduction"of national advocacy.At the same time,antibiotics cannot effectively desulfurization and denitrification processes based on activated sludge biodegradation in water,resulting in effluent discharged with antibiotics,there is a potential threat to the water environment and human health.Because of high resistance microalgae,efficient removal of nitrogen and phosphorus in water and carbon dioxide synthesis of carbon-neutral fuel capacity,are widely used in municipal and industrial wastewater treatment.In order to solve the conventional pharmaceutical wastewater treatment process CO₂ emissions and residues of antibiotics and other problems,the present Construction microalgae efficient wastewater processing system for implementing synchronization denitrification and desulfurization removal of antibiotics.Reveals the ways and mechanisms of microalgae to remove sulfide in wastewater and antibiotics,it demonstrated the application potential of microalgae wastewater treatment.Symbiotic algae system constructed to further improve the removal efficiency of desulfurization and denitrification of wastewater and the synchronization of antibiotics,illustrates the interaction mechanism between Phycomycetes interaction mechanism,microalgae processing techniques have practical applications in the theory of Pharmaceutical Wastewater support.Firstly,the processing system inquiry microalgae wastewater sulfide removal efficiency of nitrate and,during removal and affect the growth and metabolism of the microalgae.Found sulfide 100 mg L^-1 can be completely oxidized to thiosulfate microalgae and sulfates,sulfates may then be assimilated microalgae.At 50 mg L^-1under conditions of low concentrations of nitrate,sulfide significantly inhibited the growth of microalgae.Elemental analysis found the proportion of cells of microalgae nitrogen assimilation efficacy sulfide had no effect,while significantly inhibited the sulfur assimilation efficacy.Further analysis of the expression of metabolites associated with the metabolism of sulfur removal process microalgae sulfide under low nitrate conditions cells,was found to suppress the sulfide synthesis of cysteine and methionine microalgae cells,and induces glutathione Gan expressed peptides.Further,the microalgae can be fixed in the system and inorganic carbon source into biomass.Sulfide removal process highest yield of unsaturated fatty acids and carbohydrates,respectively 43.35 and 312.54 mg L^-1 d^-1.By metabolomic analysis found that sulfide can promote the synthesis of microalgae carbohydrates.Secondly,microalgae explored wastewater treatment system removal efficiency typically antibiotic ciprofloxacin（CIP）and sulfadiazine（SDZ）.In this study,an optimal ciprofloxacin（CIP）and sulfadiazine（SDZ）removal efficiency were achieved100%and 54.53%with carbohydrate productivity of>1000 mg L^-1 d^-1 in microalgae system.Meanwhile,the carbon dioxide fixation rate up to 2500-2600 mg L^-1 d^-1.In this process,the proportion of biodegradation of CIP and SDZ 65.05%and 17.05%,respectively.Adsorption performance further found that microalgae CIP is 10 times of SDZ.By confocal Raman microscopy and Zeta potential detecting found CIP positively charged（10.20 m V）than negatively charged SDZ（-2.55 m V）more readily adsorbed micro-organisms algae.Meanwhile,microalgae extracellular polymeric substances（EPS）proteins and polysaccharides provide more binding sites to promote and CIP microalgae closely,leading to greater access to the CIP is biodegradable within the microalgal cells.Meanwhile,it discloses a CIP and SDZ photolytic and biological degradation pathways and mechanisms.Calculated and evaluated all toxic degradation intermediates,demonstrate that all produced by microalgae treated intermediate degradation products have not aquatic environment and health hazard,and no inhibitory effect on the subsequent bioethanol production process.Finally,increasing the effectiveness of the desulfurization and denitrification of wastewater pharmaceutical,building efficacy and mechanisms Chlorella sorokiniana24 and oxidizing sulfur denitrifying bacteria Pseudomonas sp.C27 symbiotic system for desulfurization and denitrification of wastewater inquiry.Maximum sulfide and nitrate removal rates were 0.11 and 0.19 mmol L^-1 h^-1.It found that this process may reduce the toxic effects of Pseudomonas sp.C27 sulfides on Chlorella sorokiniana24 and photosynthetic efficiency.Chlorella sorokiniana 24 can improve synchronization Pseudomonas sp.C27 desulfurization and denitrification performance,and to reduce their toxic effects sulfide and oxidative stress.On this basis,we build a symbiotic algae-based granular sludge system.Compared with the granular sludge system,alginic symbiotic system sulfide removal rate increased by30%-50%;the efficiency of nitrate removal rate of 21.71%-25.44%;wastewater removal rate is typically the maximum CIP and antibiotics were SDZ increased by20%and 28.57%.Meanwhile,symbiotic algae systems also improve the recovery of elemental sulfur and reduction of emissions of greenhouse gases in the wastewater treatment process of N₂O.This study demonstrates the practical value of microalgae in wastewater treatment,and provides a new perspective for the development of pharmaceutical wastewater treatment coupling biomass energy production technology.