The Research On Modeling Of Bio-electro Denitrification In Wastewater Treatment

Nitrate contamination of water has become a serious problem we faced nowadays. At present, great progress has been made in waterwater denitrification. Methods such as physical, chemical and biological denitrifications have been well developed and widely applied, among which, biological methods has been developing the fastest and has become the most widely used ones. There are always some problems, however, in pure biological denitrification, for example, the amount of carbon source is hard to control, denitrification is not complete, and so on. these processes are usually complex and require careful monitoring of a carbon source, and post-treatment process is often required to remove the excessive amount of carbon source. As a newly developed method, the bio-electro method (or biofilm-electrode method) combines the advantages of electrochemical and biological methods simultaneously, overcomes some disadvantages of tranditional methods, grealy simplies the process and significantly improves denitrification efficiency. It has been paid great attention and has been progressing rapidly in recent years.In this paper, the research achievements obtained by researchers home and abroad in wastewater denitrification were summarized, various denitrification methods are compared, and the progress of bio-electro denitrification in both experimental and modeling study as well as the main problems exist during the treatment process were given a concrete analysis and estimation, the reaction mechanism of denitrification was further investigated. Reffering to the wastewater treatment practice, a double electron donor model was established and further developed on the basis of Sakakibara model and other achievements in this field. Takeing into account mass transfer, biochemical reaction, electrochemical reaction, electric field, buffer liquid and other effect factors, the model simulated the real denitrification process in biofilm quite well. The effect factors were analyzed and discussed. An optimization was made to the whole process. This study further enriched the bio-electro denitrification theory, and provided a basis for the further development and application of this technology.Currently, bio-electro denitrification remains in experimental stage, and the theory research in this field is far lagged behind. The established kinetic models are basically semi- experiential and inadequate for comprehensive guidance. On the other hand, most models were simplified to certain externt, and there are still a lot of factors...