Study On Simulation Of Landscaping Water Eutrophication And Its Ecological Remediation Technique

Maintaining quality of landscaping water is mainly to control the content of COD, TN, and TP and growth of algae, on order to keep the water body limpid and clean. For Because of its characteristics of closed and quiescent conditions, urban wastewater treatment techniques could not be applied in this environment. This study was carried following ecology principle, ecological controlling was carried according to substance inputting and outputting contemporary. Analyzed the contamination process of static landscaping water in the Northern and the algae succession rule, to transit and decompose the contamination, biological intensify and ecological craftwork were integrated together to accelerate the adsorption , oxidation and decomposing of contamination by microbiological system.Tank microcosm has been used to simulate the eutrophication process of static landscaping water body in Northern China. It was concluded that water temperature and illumination had remarkable effect on biomass and biodiversity of algae. The relation coefficient between them and Chlorophyl-a were 0.84 and 0.75 respectively. The coefficient between TN, TP and Chlorophyl-a were 0.84 and 0.54. NH₄⁺-N affected the growth of algae best and then was NO3--N.Eutrophication came from bottom mud when no more extrinsic pollutant matter importing into the water. The phytoplankton changes with the development of various dominant species. The dominant category changed as follows: Cyanophyta was dominant category at the middle stage and disappeared in the last stage, and then changed to Cyanophyta with time. Xanthophyta held the dominance at the last eutrophication stage for its capability of low temperature. Effect factors including that water quality, mud character, climate and geography conditions.Nine biodiversity indices calculated on the basis of phytoplankton data were studied for their usefulness for eutrophication studies in landscaping water body. As follows: Margalef's,PIE,Menhinick's,Shannon-Wiener,Simpson's,McNaughton's dominance index,Species,OD,Monk , as a tool for eutrophication assessment in Landscaping water body , Monk index and Menhinick's index were the best suitable for token the contamination development. Effluent was recycled at different period in dynamic parts. Data showed that removal rate of ammonia nitrogen (NH₄⁺-N) were all higher than 85% in each pattern. Improving recycling rate could promote removal of nitrous contamination. The lowest concentration of TP was 0.079mg/L. TP removal was slow and unstable. Environment temperature was the important factor for NH₄⁺-N and TP removing; the plant favored for the removal of TP and organic matter and had little effect on the TN removal. DO was kept high when the recycling period was improved to 1h and 1.5h. C/N was improved then. Removal ratios of NH₄⁺-N,NO₂^--N and TN were promoted with recycling rate improving. Improving of recycling rate made the nitrification more rapidly and completely, the transition approach of nitrogen was shortened. And more rapid the recycling rate was, more direct was the transition.Screening and domesticating dominant consortium to intensify remedying process, aboriginal colony and naked substrate was contrast. Abundant nitrous and nitride bacterium in dominant colony made nitrification swift and thorough, cut accumulation of middle production and hasten nitrogen removal. Dominant consortium kept high activity in long time, which intensified removal of nitrogenous contamination. Cooperation of multi-colony enhanced P removal capacity of system.Removal efficiency of NH₄⁺-N by naked system was rapid, the last concentration was lower than 0.5mg/L. Cutting down ion exchange by bio-layer could be made up by nitrification by dominate bacterium. Ion exchange rate and nitrification rate increased evidently along hydraulic distance in dominant colony system, but they decreased in the other two systems.The experiments of ecological interdiction showed that, Rain water made NH₄⁺-N concentration raised up in short time and affected nitrification of NH₄⁺-N.Organic contamination consumed DO in water that weaken nitrification conditions. Negative and positive ion was added by rainwater, ion releasing in water-bottom interface prolonged, and pH of cover water fluctuate great in the process, which prolonged system stabilization time. The ecological filter could remove NH₄⁺-N more than 80% from rainfall , road surface flowing contamination.The system could remove TP and organic contamination of high concentration. When the beginning concentration was 0.1mg/L,1mg/L,10mg/L, Cu,Pb,Zn could be removed mostly in 1h.From economy analyses contrasting of physical method-mud dredge up, adding chemical medicament and biological remediation, we concluded that ecological engineer could combine physical, chemical and biological reaction mechanism; it was high efficient, low consumed and low expenses for cleaning and maintaining landscaping water.