Selecting The Microalgae With The Ability To Degrade The Biogas Slurry And Municipal Sewage And The Outdoor Treatment Research For Domestic Wastewater

Wastewater problems have become one of the most important questions in polluting the environment,and the increasingly complex compositions of sewage may make the sewage treatment more difficult,especially the nutrients like nitrogen and phosphorus in wastewater.Microalgae can remove contaminants from sewage by taking advantage of the Organics and nutrients in the sewage for cell growth.We filtrated and separated the algal species from water samples and soil samples collected from nature that can grow in the biogas slurry as well as domestic sewage,and studied the decontamination ability of these algae for both wastewater.By using a specific sewage medium,69 strains and 65 strains of algae species are separated that are resistant to biogas slurry and domestic sewage,respectively.And these 134 strains of algae species constitute a pool of algae resource for sewage treatment.Based on the morphology,these algae species can be divided into Chlorella,Scenedesmus,Cosmarium,Chlamydomonas,Nostoc and so on.The screened algae species,which have good growth potential and tolerance to two kind of sewage,are applied to wastewater treatment.For biogas slurry,the selected algae species are 10,13,ZB,28,31,33,algae species 28 has better degradation capacity for biogas sludge than the other algae species.For algae species 28,the degradation rates of COD,TN and TP were 39.96%,85.78% and 71.07%,respectively.For domestic wastewater,the selected algae species are BS,MY-1,6803,MY-2,ZB.Algae species ZB is better than the others algae species on the degradation ability.For algae species ZB,the degradation rates of COD,TN and TP were 80.32%,90.98% and 67.61%,respectively.Because of high growth rate of algae species ZB,it can be used as the dominant algaes for the outdoor wastewater treatment.The algae species ZB was short-term treated in the outdoor treatment experiment with the reaction apparatus,and the treatment effect was achieved.The outdoor degradation rates of COD,TN and TP for the wastewater were 93.60%?94.61% and 84.96%,respectively.It is apparently that the outdoor wastewater treatment can make preparation for the next plot-scale research.