Research On Integration Technology And Complete Equipment Of Urban Landscape Waters Treatment

Pollution and eutrophication of urban landscape waters in our country are getting increasingly serious recent years.Traditional treatment technologies have many disadvantages.This research is a component of scientific research program of Shanghai Science and Technology Committee : Development and demonstration of ecology maintenance complete equipment for rivers of central town.Traditional flocculation-fiotation,bio-contact-oxydation and filtration technologies were improved, optimized and combined,complementarity and synergism of them were studied,optimized process parameters and operating conditions were obtained,and landscape waters treatment integration technology and complete equipment were studied and developed. Integration technology and complete equipment which combined physics,chemistry and biology functions,are efficient,stable,flexible,and universally applicable to landscape waters which were slightly-polluted and eutrophied.During flocculation-flotation experiment,a coagulant removing algae,turbidity and phosphorus efficiently were produced by single-factor comprison and orthogonal experiment ,influence of dosage,hydraulic surface load and flocculation time to treatment effect were studied, and reasonable operating parameters were determined. Under the conditions of 20mg/L dosage,2.0mm/s surface load and 4.5min flocculation time,average removal rates of algae,turbidity,TP,TN and COD_Cr reached 93.2%,89.5%,74.9%,33.8% and 43.5% respectively.During biology unit experiment,three kinds of packing materials(elastic packing, combined packing,zeolite)were compared.Zeolite is far better than other two in regard to treatment effect.Influence of HRT to treatment effect of zeolite-packed unit were studied.Pollutant removal rate decreased with the shortening of HRT.However,18.7% COD_Cr and 50.3% ammonia nitrogen removal rate can be obtained with 10min HRT.Zeolite which can selectively adsorb ammonia nitrogen has synergy with nitrifying bacteria in regard to ammonia nitrogen removal,which can improve adaptability of biology unit to change of effluent quality,and is helpful to biofilm culture and restarting. During filtration experiment, fibre was used as filter,and horizontal-thin-filtration technology was developed,which overcomed disadvantages of traditional filtration.Influence of filtration velocity ,filter thickness and compactness to filtration performence were studied,and optimized parameters were obtained.Under the conditions of 110kg/m³ fibre-ball loading density,400mm filter thickness and 16 m/h filtration velocity,average turbidity of effluent is 0.8NTU.Cycle water productivity reached 384 m³/m², with 24h filtration cycle and 712mm head loss.On the basis of unit experiments,flotation,biology and filtration technologies were incorporated to complete equipment,complementarity and synergism of them were studied,optimized process parameters and operating conditions were determined,and treatment effect were investigated.Complete equipment is able to remove 96.3% algae,91.9% turbidity,83.8% TP,39.5% TN,53.3% ammonia nitrogen and 57.0% COD_Cr averagely. It is able to improve and maintain water quality effectively,and has remarkable advantages and bright practice prospect.