Study On The Effects Of Water Purification By Bacteria-alage-floating Bed And Its Mechanism

As the results of the complex topography,low urbanization,and the difficulty of collecting sewage,centralized sewage treatment plant for Barerhe area is hard to adopt.As one of the most effective ways in water treatment,ecological sewage treatment technology can be applied to solve the problems.Ecological floating bed technology,one of the ecological treatment technologies,which is easy to operate,low cost and can take advantage of the landscape,has been widely used in wastewater treatment.Of particularly concern is the bacteria-algae symbiotic system,which can improve not only the sewage resistant ability,also the decontamination ability.In this paper,a bacteria-algae-floating bed compound treatment system was described,based on its ability of sewage treatment;the contamination removal mechanism was investigated.The main research results of this paper are described in detail as following:Local plants of canna,calamus and cyperus were used to construct ecological floating bed to treat the household sewage and the results showed that: in summer,canna is better than calamus and cyperus in sewage treatment,however,calamus is better than canna in winter.The accumulation of nitrogen and phosphorus varied in different plants organization along with the seasons.Cellulose packing and elastic packing ecological floating bed were constructed in summer,in cellulose packing ecological floating bed more bacteria(7.6×1011cfu/L)was found,and the concentration of TN,TP reduced from 23.8mg/L,1.51mg/L to 5.6mg/L,0.29mg/L,the removal efficiency of TN,TP were 76.5%,80.7%,respectively.Environmental factors which causing the eutrophication of the local water environment were studied.The research indicated that the optimal condition for algal growth were temperature(24?),phosphorus(1.02 mg/L),light(3500 lx)and stirring speed(60 r.p.m).Bacteria-algae-floating bed multi treatment system was constructed to investigate the spatial distribution of nitrogen cycle bacteria and community evolution of phytoplankton in wastewater treatment.The results showed that the distribution ofnitrogen cycle bacteria and community evolution of phytoplankton was clearly different in sewage concentrations.The microorganisms amount in calamus roots were higher than water environment.From the perspective of biological diversity,multi treatment system tend to effect the ecological communities' adjustment and promotion of biological diversity in high sewage concentration,in low concentration sewage,the multi treatment system tend to inhibit the growth of phytoplankton.Through the research on bacteria-algae-floating bed multi treatment system,it was found that mixed algae possessed the highest removal efficiency of nitrogen and phosphorus,the concentration of TN,TP reduced from 29.37mg/L,2.85mg/L to11.72mg/L,0.58mg/L.The removal capacity of nitrogen and phosphorus were different by different algaes;chorella had the highest TN removal efficiency(52.4%)while synedra had the highest TP removal efficiency(74.1%).calamus was better than algae in ammonia and phosphorus removal,while algae had a better TN removal than rate calamus.The multi system can effectively treat the sewage with low investment,which would play an important role in ensuring water quality of Baierhe river,Shending river and Danjiangkou Reservoir,aslo played a positive role in economic and social development.