Method for enhancing denitrification of subsurface flow constructed wetland by adding alkali-heat-treatment maize straw carbon source

Abstract

The invention discloses a method for enhancing the denitrification of a subsurface flow constructed wetland by adding an alkali-heat-treatment maize straw carbon source, and belongs to the technical field of the sewage treatment of constructed wetlands. The method comprises the following steps of (1), using maize straw as a raw material, cutting the maize straw into equal-length small segments, washing the equal-length small segments by using water to remove dust, drying the equal-length small segments, proportioning the equal-length small segments according to a solid-to-liquid ratio of 1 to 30 by using a 1 percent NaOH solution, heating an obtained mixture for 1h at a constant temperature of 90 DEG C in a water bath, taking out the mixture, and drying the mixture to a constant weight; (2), carrying out a static release experiment on alkali-heated maize straw carbon source, determining the carbon source release amount and the nitrogen source release amount of the alkali-heated maize straw carbon source through a fitted curve, and calculating the addition amount of the carbon source in the wetland according to that the ratio of the influent COD (Chemical Oxygen Demand) concentration, the TN (total nitrogen) concentration and the influent flow of the subsurface flow constructed wetland to C/N (carbon/nitrogen) of sewage is equal to 7 to 1 is an optimal carbon nitrogen ratio; (3), adding the alkali-heated maize straw carbon source at the bottom of a soil layer and at the upper part of a gravel layer of the wetland according to the configuration and the running mode of the subsurface flow constructed wetland. By using the method for enhancing the denitrification of the subsurface flow constructed wetland by adding the alkali-heat-treatment maize straw carbon source, the TN removal rate of the subsurface flow constructed wetland is increased by 31.07 percent.

Description

technical field [0001] The invention relates to a subsurface flow constructed wetland enhanced denitrification method for adding alkali to heat corn stalk carbon sources, which belongs to the technical field of constructed wetland sewage treatment and relates to a method for enhancing the denitrification treatment effect of constructed wetlands by adding an external carbon source. technical background [0002] The use of subsurface flow constructed wetlands to deeply purify the effluent of sewage treatment plants has been widely used in my country. However, due to the low carbon and nitrogen ratio of the effluent of the sewage treatment plant, the activity of denitrifying bacteria in the wetland is inhibited, and the denitrification efficiency of the subsurface constructed wetland is greatly reduced. Therefore, in recent years, enhancing the denitrification efficiency of subsurface flow constructed wetlands by adding carbon sources has gradually become one of the hot researc...

AI Technical Summary

Problems solved by technology

[0004] The technical problem solved by the present invention is to overcome the low carbon-nitrogen ratio in the effluent of the sewage plant, inhibit the activity of denitrifying bacteria, and cause the low denitrification efficiency of the subsurface constructed wetland

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