Research On The Transformation Rule Of Nitrogen And Technological Process In CRI

Constructed Rapid Infiltration (CRI) system has the various advantage, will play a very important role in wastewater treatment. Although CRI has the higher velocity of percolation and the stronger material removal rate of organic contaminant, the material removal rate of nitrogen and phosphorus is lower. It's difficult to reach ((the discharge standard of pollutants for municipal and town sewage plant)) primary A standard. So this thesis, chose the river alluvial sand and marbles as percolation materials, and take rural domestic waste as the research object, to carry on the soil pillar's experiment indoors. The research lies on the transfer, transformation and degradation rule of pollutants inside the quick pond of percolation, and get the removal rule of pollutants in CRI, especially nitrogen. Then use those rules and mechanism to change the structure of pond and the method of operation functionally, and so on, in order to improve the disposal rate of pollutants(especially total nitrogen) in all directions. The researching results are used for guide the engineering project, are favorable for the further popularization and application of CRI..Through monitoring the organic matter and nitrogen pollutant consistency in CRI, it analyzes the pollutant transforming rules of different section. The research indicates that the transforming rules of COD is simillar to ammonian, namely the disposal rate increases gradually with the deepth of poud raising. But the disposal rate focuses on the upper layer, about the scope of 90cm layer, occupied 90% of total disposal rate.The density of the nitric nitrogen straight climbs in the scope of 90cm with the increment of deepth, then decreases slowerly because of denitrification. The density of total nitrogen decreases slowerly, but the disposal rate is lower. Analysing the three kind of nitrogen transforming rules, it gets the methods of improving total nitrogen disposal rate. On the one hand, improve the reactor to increase the length of the oxygen segment, and the oxygen condition can promote the denitrifying bacteria growing; on the another hand, add the artificial carbon source to satisfy the denitrification demand for the carbon source, and then raise the disposal rate of total nitrogen. On the besis of improving the structures of percolating filter, it dose some research on the best operating parameters. The research indicates that under the condition of the 90cm segment water intake and 2:1 water ratio, the disposal rate of total nitrogen is highest. But the 30cm sand height of outside overflow pond can satisfy the system demand of anaerobic segment.The constructed experiment indicates that it's useful to increase the disposal rate of total nitrogen by improving the structure and adjusting the operating methods. The researching results are used for guide the engineering project, are favorable for the further popularization and application of CRI.