Algae Removal In Eurtrophic Water

The purpose of this study is to improve the efficiency of algae removal by enhancing coagulation and filtration and analyze the efficiency of all kinds algae removal in the every phase of the processing and remove remained algae from disposed water.Test of enhanced coagulation with polysilicon ferric sulfate,polysilicon ferric chloride,ferric sulfate,polyalumoferrochloride,polysilicon aluminum sulfate,polyaluminium chloride and polysilicon aluminum chloride upon algae removal are described. Results show that the efficiency of algae removal by enhanced coagulation with polyalumoferrochloride and polysilicon aluminium sulfate is higher than with others. At the same time,we further study the affection of the coagulant aids active silica acid and oxidizing agent hydrogen peroxide upon the efficiency of coagulation. Results show that the suitable preoxidation and adding coagulant aids can enhance the coagulation effect. The best dose are:[Fe3++Al3+]/[SiO2]=l/2 for active silica acid and 4mg/L for the oxidizing agent,.The results also show that the filtration effect is improved by the sand coated with metal oxide,and coagulation which is combined with filtration can enhance the efficiency of algae removal. The best efficiency of algae removal is 99%,and this technique can reduce the dose of coagulation agent.At last,this study analyzes the efficiency of all kinds of algae removal in the every phase of coagulation - filtration processing. It is showed that all kinds of algae could be approximately removed except gloeocapsa minima whose grain size is about 2.Sum. When the water is secondly filtrated by active carbon column,the content of gloeocapsa minima is reduced greatly and its efficiency removal can reach to 99.4%.