Research On Treatment On Heavy Metal Wastewater By Coupled System Of High Rate Algal Pond And Constructed Wetlands

As an algae-bacteria symbiotic system, High rate algal pond（HRAP）and Constructedwetlands （CWs） has become an important choice of low-cost water treatment technologyaccording to ecological characteristics.By building HRAP and CWs complex ecosystem coupledto form algae-bacteria-Metabolic symbiosis wetland submerged plants and automatic aerationwetland to heavy metal co-evolutionary process.By experimental analysis of factors affecting thecoupling system to remove heavy metals,comparing various combinations of heavy metal removal,to determine the coupling system operation optimization parameters.Combined with experimental data and theoretical analysis shows that: Environmental factorssuch as temperature, light, nitrogen and phosphorus ratio by influencing the growth of algae andbacteria to influence the removal of heavy metals.Temperature and light intensity are significantfactors affecting the concentration of the proliferation of algae,illumination time and phosphorusratio is not a significant factor.With increasing water pH, adsorption of heavy metals in the matrix is increased,Matrixadsorption of heavy metals:yellow sand> fine quartz sand> coarse quartz sand.Sprinkler removalof heavy metals better than drip irrigation.Enrichment of Under unit weight canna roots absorbmuch larger than the enrichment of stem and leaf.Compared to spray, root enrichment in largequantities of heavy metals in drip condition.but enrichment stems under water spray is greater thanthe amount of of drip water enriched.After coupling system treatment, Zn, Cr, Pb three kinds of heavy metal removal rate reached94.4%,93.2%,98.8%,effectively removes heavy metals from waste water.In coupling system,HRAP play a major role in the removal of heavy metals, the removal of60%of the totalamount.Removal of heavy metals mainly rely on adsorption metabolism of algae, Zn, Cr, Pb and precipitation depend on the proportion of microbial metabolism to remove three heavy metalswere8.7%,21.4%,19.1%.At16000cells·mL-1algae concentration per unit volume of efficientalgae pond algae chromium, zinc and lead ultimately adsorption were352.74ug,2657.28ug,1443.86ug.1g dried algae powder can absorb chromium, zinc, draw the amount of lead were0.92mg,4.34mg,2.05mg,The total amount of the entire pre-treatment to remove heavy metal stemcell algae is substantially equal to the water adsorption of heavy metals, suggesting that the use ofalgae powder winter can remove heavy metals from waste water.Under drip water canna roots enrichment unit weight Zn, Cr, Pb, respectively925.6mg,261.6mg,494.1mg,higher than under sprinkler irrigation water Zn, Cr, Pb of540.9mg,86.1mg,352.3mg.Under drip irrigation shoots heavy metal content relative to the control did notsignificantly increase.The heavy metal enrichment of stem and leaf spray irrigation water is muchhigher than drip irrigation.