Method for treating nitrate nitrogen in underground water via calcined pyrite

Abstract

The invention discloses a method for treating nitrate nitrogen in underground water via calcined pyrite. The method is characterized by comprising the following steps: filling a filter column by taking calcined pyrite particles and limestone particles as lower-layer filter materials, adhering thiobacillus denitrificans and iron-oxidizing bacteria relying on nitrates to the surfaces of the lower-layer filter materials and then filling limonite particles above the lower-layer filter materials to serve as upper-layer filter materials; and taking and injecting the underground water into the filter column in a direction from bottom to top and controlling hydraulic retention time within 4 to 24 hours so as to carry out chemical and biochemical reactions on the nitrates contained in the underground water and the filtering media, thereby converting the nitrates into nitrogen to be removed. The method is high in treatment efficiency and low in cost.

Description

1. Technical field [0001] The invention relates to water treatment technology, mineral material processing and application technology, in particular to a water treatment technology containing nitrate nitrogen. 2. Technical Background [0002] In recent years, with the development of industry and agriculture in the world, the concentration of nitrate in groundwater, which is the main source of drinking water, is constantly increasing and tends to deteriorate. High concentrations of nitrates in drinking water have been attributed to people's direct or indirect overuse of nitrogen-containing substances. Although nitrate itself is not harmful to the human body, after ingestion of nitrate into the human body, it is partially reduced to nitrite under the action of reducing bacteria. Nitrite easily reacts with hemoglobin in the blood to form methemoglobin, which affects the blood's ability to transport oxygen. Infants are more sensitive to the potential toxicity of nitrates than ...

AI Technical Summary

Problems solved by technology

[0012] First, pyrite belongs to the pair of sulfides. Two sulfur atoms are covalently bonded to form a dumbbell shape. The chemical bond is strong. The chemical oxidation and biological oxidation speed of pyrite are very small, and the required hydraulic retention time is relatively long. Autotrophic microorganism Thiobacillus denitrificans uses pyrite to denitrify inefficiently;

[0013] Second, Thiobacillus denitrificans is an anaerobic microorganism and cannot play a role in an aerobic system, but water always contains a certain amount of dissolved oxygen. How to use technology to provide anaerobic ecological environment for anaerobic microorganisms such as Thiobacillus denitrificans , promoting the metabolism of such microorganisms to reduce nitrate is the key issue;

[0014] Third, some anaerobic nitrate-reducing bacteria such as Thiobacillus denitrificans are autotrophic bacteria with slow value-added rate and poor treatment effect