The Research On The Utilization Of Sulfate Based On The Cultivation Of Chlorococcum Sp.GD

With the development of industries such as power plant,food fermentation and light industry,the production and discharge of sulfate-containing wastewater has caused serious pollution to the environment.The use of microalgae to treat sulfate is a potential environmental biotechnology.However,there are few reports on the utilization of sulfate by microalgae.The utilization efficiency of sulfate is relatively low,and the key influencing factors are not yet clear.All drawbacks above have become the bottleneck restricting the development of this technology.Therefore,it is crucial to find effective control measures for improvement of sulfur utilization efficiency of microalgae.Considering the fact that SO₄^2-is the main form of sulfur contaminants in sewage,Chlorococcum sp.GD was used to explore its response to SO₄^2-and to strengthen utilization of SO₄^2-further.The main findings are as follows?1?The response of Chlorococcum sp.GD to SO₄^2-was investigated.The results showed that the growth status of Chlorococcum sp.GD was excellent and the removal efficiency of pollutants was high?the removal efficiency of COD,ammonia nitrogen and phosphorus were 94.37⁹4.81%,93.10⁹6.19%and 79.11⁸8.81%,respectively?in simulated wastewater containing different concentrations of SO₄^2-?0²71 mg/L?.In sulfate-free sewage,its growth was inhibited and pollutants removal efficiency was reduced?the removal efficiency of COD,ammonia nitrogen and phosphorus were 33.33%,56.27%and 27.86%,respectively?.The activities of superoxide dismutase?SOD?,catalase?CAT?and peroxidase?POD?were significantly enhanced,and the activity of microalgae cell was significantly reduced.In the context of this experiment,although the growth of Chlorococcum sp.GD was not inhibited,the utilization efficiency of SO₄^2-was low.The removal efficiency of SO₄^2-was only 6.49%in sewage containing 136 mg/L SO₄^2-.?2?The growth characteristics and sulfur utilization patterns of Chlorococcum sp.GD with different inoculum concentrations,nitrogen concentrations and carbon concentrations were investigated.It was showed that Chlorococcum sp.GD could grow well in sulfur-containing wastewater regardless of above parameters.However,sulfur utilization was affected by the inoculum concentration?50⁷50 mg/L?,nitrogen concentration?ammonium chloride:13⁷6 mg/L?and carbon concentration?glucose:1000¹0000 mg/L?.Within the certain concentration range of every parameter,the sulfate removal efficiency of Chlorococcum sp.GD was 19.96³1.32%,23.38³1.23%and 35.62⁴6.65%,respectively.Compared to the control experiment?sulfate removal efficiency was less than 10%?,the utilization efficiency of SO₄^2-by Chlorococcum sp.GD was greatly increased through the regulation.There were also differences in enhancing the sulfur utilization efficiency of Chlorococcum sp.GD via different parameters.Carbon and nitrogen regulation,by contrast,was a potential regulatory method for sulfur utilization by microalgae.In view of the fact that carbon and nitrogen were extensive and easily accessible?eg,municipal wastewater and aquaculture wastewater etc.?,related research coupled the removal of pollutants?such as carbon and nitrogen?with the removal of sulfur pollutants.The biomass could also be used for downstream processing.The results of this study would help to solve the outstanding problems of sulfur pollution and realize the resource recycling and harmless disposal of waste materials.