Study On Enhanced River Denitrification With The Core Of Solid-phase Carbon Source Technology

Dianchi Lake, located in Kunming, Yunnan Province, southwestern border territory, is the lowest point of the basin. The water quality of the Lake was worsening in the past two decades, with a small drainage area, less water, and the absence of cross-boundary water supplies,. Dianchi Lake is a26key monitoring lakes (reservoirs) is the only one severe in lakes in the2011environmental bulletin of China.Over the past few years, the state give a large number of inputs in Dianchi Lake, and the trend of lake water quality continued to deteriorate has been curbed, but it is still a distant goal to reproduce the "Plateau Pearl" lake water environment. In governance, if we only focus on a simple governance lakes, it is difficult to achieve a fundamental improvement of the Dianchi Lake water quality. The subject of tracing the source of new and transportation to Dianchi pollutant load which is one of the main source of the river for enhanced denitrification technology research carried out based on the solid phase of sustained-release carbon source technology urban polluted river. Throngh these ways,we want to complete the subduction of total nitrogen index,as the core pollutant load reduction and the restoration of the river water, the formation of a polluted river pollution load reduction of integration technology and system control program, the Dianchi Lake basin water environment as a whole to improve the goals and lay a solid foundation.The micro-aeration biological filter bed and biological contact oxidation are the two contrasting processes of the river early preconditioning in this experiment. It subsequently get into the solid contrary nitrification reactor, in order to achieve the comprehensive removal of CODcr of river water, ammonia and total nitrogen pollutants, and the following conclusions:(1) The carbon oxidation segment completed84.17percent of the CODcr load reduction of the total abatement amount, and for ammoniaload abatement in the nitrification stage, ammonia nitrogen load abatement in the nitrification stage completed84.17percent of the total abatement amount., in the high pollution load (water CODCr concentration of138~190mg/L) of CODcr abatement.(2) The abatement of ammonia load did not show in the high pollution load of the law, but rendered in carbon oxidation, nitrification stage reductionmore balanced situation, the two pollutants while balancing the decline in two phases, in the low pollution load (influent CODCr concentration in the65~78mg/L) of CODCr,(3) The denitrification rate of the PBS as a carbon source and biofilm carrier follows the first-order kinetics for the establishment of the plug-flow, and the solid contrary nitrification reactor kinetic model of the low nitrate effluent denitrification at20℃verifies that the concentration of nitrate reduction process follows the equation: ln(－lnse-so)=－0.9799×lnL+ln0.006(4) The device for total nitrogen removal, mainly through the final stages of solid contrary nitrification, gets a total nitrogen overall removal efficiency of49.91%. In the BAF processes on the4th pool, the solid contrary nitrification stage compared with the ordinary anaerobic pre-reaction on the abatement of NO3-N concentration is5.47times and2.73times of the water treatment rate of relative reaction segment. Under the same conditions, the denitrification rate in the general anaerobic reactor is much lower than the rate of solid contrary nitrification.(5) The concentration of nitrate in water, shows an upward trend in response to nitrification and denitrification, but in the reaction process, the nitrate concentration remained at1.5mg/L, which means no nitrate accumulation.(6)The pH value of treated sewage shows a decline in nitrification segment denitrification segment. Overall, the pH value at all stages is maintained between7to8, meaning alkalinity would not be enough, without additional investment to increase the pH.(7)Through the economic evaluation of the process, the handling capacity of1000m3/d with micro-aeration biological filter bed and solid-phase carbon source reactor processing the city’s polluted rivers, one-off project investment is36.84million which means the unit investment in sewage treatment is368.4yuan/m3, lower one-time investment of unit processing capacity than the size of considerable general biological treatment processes (340~480yuan/m3). The running costs of on the river treatment with this craft is about0.331yuan/m3.The experiments shows that the micro-aeration biological filter bed contact and bio-oxidation pretreatment processed with solid contrary nitrification reactor has better removal effect in the urban polluted river water, with an excellent removel rate of ammonia and total nitrogen. The subdection of COD and ammonia nitrogen shows different patterns of degradation in different organic load and denitrification reaction followed first order kinetics equation. Practice has proved that this process combination technology for low carbon nitrogen ratio pollution of the city-river, is an efficient, economic approach and provides a new idea for the surface water environmental governance in China.