Experimental Study On Wastewater Treatment Of Lignocellulose-based Algae Biofilms

With the improvement of material life,a large amount of wastewater containing nitrogen and phosphorus is discharged into the water,resulting in eutrophication and low recycling efficiency of water resources.In recent years,more and more attention has been paid to the treatment of wastewater by immobilized algae membrane.As a cheap algal medium,wastewater can not only provide enough nutrients such as nitrogen and phosphorus for the growth of algal cells,but also achieve purifying wastewater.In this paper,a self-designed flat plate photobioreactor(FPBR)by the laboratory was used to treat the simulated sewage of specific concentration with dephosphorization,and the biochemistry characteristics of the harvested algae biomass were analyzed.Through the screening of immobilized carrier and the analysis of pollutant removal efficiency,the following results were obtained:1.Selection of cheap and readily available lignocellulose materials as carriers for algae immobilization,including sawdust(10-20 orders,30-40 orders),Bagasse(10-20 orders,30-40 orders),Grain husk(10-20 orders).In the FPBR reaction system,Chlorella vulgaris,Hydrophylla,Diplosphaera sp.MM1 were inoculated respectively and the best carrier materials of the system were selected by comparing the biomass of algae membrane on different lignocellulose carrier materials.The results showed that the biomass of the three algae on the carrier material ranged from large to small:sawdust>bagasse>husk,and showed the maximum biomass on 30-40 mesh sawdust.2.It was determined that 30-40 mesh sawdust was used as the carrier material of algae membrane immobilization,and Chlorella vulgaris,Hydrophylla,Diplosphaera sp.MM1,Scenedesmus obliquus were selected as immobilized algae species to study the effect of four kinds of algal membrane on wastewater treatment in this reaction system.The research finds that:1)carrier material sawdust has a certain removal effect on pollutants in wastewater,and the removal rates of COD,TN,ammonia nitrogen and TP are 36.60%,42.20%,39.80%,17.32%,respectively.The cumulative removal amount is 304.50mg/L,36.29mg/L,29.46mg/L and 2.60mg/L respectively.2)Chlorella vulgaris has the best treatment effect on the cell membrane of wastewater,COD,TN,ammonia nitrogen and TP removal rate were 96.47%,88.94%,93.25%,97.26%,COD,TN,ammonia nitrogen and TP effluent concentration were 27.50mg/L,9.66mg/L,4.99mg/L,0.43mg/L,the effluent met the level A urban sewage discharge standard.The next was Sargassum obliquus and Diplosphaera sp.MM1,which had the worst adaptability to this reaction system.3.The biochemistry composition of algae biomass after wastewater treatment was analyzed.The contents of protein,carbohydrate and total lipid in four species of algae(%of dry weight)were 34.59%~40.84%,22.37%~28.96%,10.07%~13.28%,respectively.C16-18 is the main fatty acid methyl ester type of four algae biomass,the corresponding theoretical productivity of biodiesel is 46.85mg/m~2/d?87.75mg/m~2/d?16.74 mg/m~2/d?28.65mg/m~2/d.