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.