Method for increasing total nitrogen removal rate for imbalanced carbon-nitrogen wastewater wetland by using aquatic plants

Abstract

The invention relates to a method for increasing total nitrogen removal rate for an imbalanced carbon-nitrogen wastewater wetland by using aquatic plants. A composite treatment system is constructed which comprises four subsystems, a stabilizing pond, a surface flow wetland, an ecological water channel, and a horizontal subsurface flow wetland; the subsystems are serially connected sequentially through a process. The method has the advantages that different species in an aquatic plant community are less competitive, the aquatic plant community is more stable, and secondary pollution due to centralized decomposition of aquatic plants is avoided; human resource cost is lower, and the decomposed organic matters may provide a carbon source for the denitrification of a wetland and increase the nitrogen removal rate; nitrifying effect and denitrifying effect can be balanced through alternation of the different subsystems and different regional anaerobic and aerobic environments in the subsystems in order to increase the total nitrogen removal rate; the general defect of poor winter purifying capacity of a wetland purifying project is overcome, and the shortage of summer carbon sources to the wastewater wetland is relieved; efficient, continuous and stable carbon sources can be provided.

Description

technical field [0001] The invention relates to a method for improving the total nitrogen removal rate of carbon-nitrogen unbalanced tail water wetlands by using aquatic plants, and belongs to the technical field of advanced treatment of tail water structure wetlands of sewage treatment plants. Background technique [0002] For nitrogen, removal mechanisms in wetlands include volatilization, ammonification, nitrification / denitrification, plant uptake, and substrate adsorption. Many studies have shown that the main nitrogen removal mechanism in wetlands is microbial nitrification / denitrification, and the amount of nitrogen removal by nitrification / denitrification accounts for more than 70% of the total nitrogen removal. Sewage treatment plants often use the A / O process, which consumes a large amount of COD, especially BOD, which causes a serious imbalance in the carbon-nitrogen ratio of the tail water, resulting in insufficient carbon sources in the denitrification process, i...

AI Technical Summary

Problems solved by technology

Sewage treatment plants often use the A / O process, which consumes a large amount of COD, especially BOD, which causes a serious imbalance in the carbon-nitrogen ratio of the tail water, resulting in insufficient carbon sources in the denitrification process, inhibiting denitrifying microorganisms, and reducing nitrogen removal efficiency.

In addition, similar to general wetlands, tailwater wetlands are plagued by large seasonal fluctuations in purification capacity and insufficient purification capacity in winter, and cannot meet the purification requirements of tail water from sewage treatment plants with relatively balanced seasonal water output.

[0003] Aiming at the low nitrogen removal efficiency of carbon and nitrogen imbalance tail water wetlands, various solutions have been developed at home and abroad. However, these methods still have obvious deficiencies in the actual application process, and the method of adding high C / N raw sewage is reasonable. It is difficult to control the feeding ratio, it is easy to reduce the quality of effluent water, and the effect is limited by the insufficient content of low-molecular organic matter in raw sewage; the method of adding low-molecular carbohydrates has disadvantages such as high operating costs and low effective utilization of carbon sources; while the method of adding plant straw At present, it is mainly in the research and development stage of the technology, and there are still disputes about the dosing method, dosing amount, dosing timing, etc., and it is difficult to meet the requirements of large-scale applications.

[0004] Reed, wild rice, calamus, Zailihua, etc. are the most commonly used aquatic plant species in constructed wetland ecological engineering; because the vigorous growth period of these aquatic plants overlaps almost completely with the vigorous activity period of denitrifying bacteria, it is difficult to select aquatic plants in Provide sufficient carbon sources during periods of high demand for microbial carbon sources (spring and summer); current selection of aquatic plant types and their configuration tend to exacerbate seasonal fluctuations in wetland purification capacity

Images