Study On The Treatment Of Phosphorus-containing Wastewater By High-efficiency PAOs And The Adsorption Behavior Of Heavy Metals By Biosorbents

Water eutrophication and heavy metal pollution are consistently critical global issues,and bioremediation is regarded as one of the most promising approaches.The purpose of this study is to use phosphorus accumulating microorganisms(PAOs)to efficiently remove phosphorus from wastewater and promote the understanding of the biosorption potential of PAOs-derived materials for heavy metals.In this work,the growth and phosphorus removal conditions of the selected three strains were optimized to further improve phosphorus removal efficiency.Three kinds of biomass adsorbents PABs were prepared from the strains.The adsorption characteristics of PABs on Cd(II),Pb(II),Cu(II)and Zn(II)were studied and the adsorption mechanism was explored by means of characterization.The main research contents and conclusions of this paper are as follows:(1)Three strains were isolated from the contaminated sediments in Hunan,which were mainly distributed in three genera,Ochrobactrum sp.,Stenotrophomonas sp.and Pseudomonas sp..The selected strains had wide environmental adaptability and high phosphorus removal performance.Under the optimal conditions,the phosphorus removal rates of strains PAB-006,PAB-009 and PAB-031 were 68.02%,98.91% and76.55%,respectively.Strain PAB-006 was effective in removing organophosphorus and inorganic phosphorus,while strain PAB-009 and PAB-031 mainly removed organophosphorus.The optimum phosphorus removal conditions for PAB-006 and PAB-009 were p H 7.0 and 30℃,while p H 5.0 and 20℃ for PAB-031.(2)The adsorption of Cd(II),Pb(II),Cu(II)and Zn(II)on PABs showed that the adsorption capacity increased with the increase of p H value,ionic strength and organic matter content.The biosorption capacities of Cd(II),Pb(II),Cu(II)and Zn(II)were calculated to be 67.84,80.23,50.56 and 63.07 mg/g for PAB-006,59.99,87.71,39.26 and 63.07mg/g for PAB-009 and 68.31,85.43,38.97 and 62.85 mg/g for PAB-031,respectively,which were better than most biosorbents previously reported.The biosorption was a hybrid chemical reaction–biosorption process.Coordination was the main mechanism involved in the biosorption process.Surface complexation,ion exchange and electrostatic interaction also promoted the biosorption.The biosorbent PABs has excellent bioadsorption and regeneration performance,with the advantages of environmental protection,stability,no secondary pollution and low cost.