| Hydrogen peroxide oxidation and activated sludge methods are introduced in this article to treat cyanide wastewater in the laboratory scale. It has an important value of industrial application.Results indicate that hydrogen peroxide oxidation method could treat the cyanide wastewater effectively. The removal rate could reach above 94%.The suitable conditions in the experiment are in the following. The pH value is 9, the hydrogen peroxide amount is 1000mg/L, the catalyst concentration is 2mg/L, and the reaction time is one hour.Due to the cyanide toxicity to microbe, the toxicity of cyanide to main strain (Aerobic bacteria, nitrifying bacteria, denitrifying bacteria) is researched. The results indicate when the cyanide concentration ranges from 0 to 2.0 mg/L, cyanide has an inhibitory effect on the activity of sludge, but not lethal. Nitrifying bacteria is more sensitive than other strains to cyanide. Nitrifying process is totally inhibited, when cyanide concentration is 2.0 mg/L. The inhibitory effect of cyanide on de-nitrification process is mainly on that nitrate is converted into nitrite. Cyanide is firstly turned into ammonia nitrogen. Then ammonia nitrogen converts to nitrite and nitrate. In the low cyanide concentration range (<2.0 mg/L), microorganism could degrade cyanide.Pilot plant is established to estimate the effect of activated sludge removal of cyanide. The results indicate that pilot plant has good removal effect for cyanide. The remove rate is above 90%. At the same time, the pilot can remove such as COD, ammonia nitrogen and total nitrogen effectively. The removal rate is the same as the wastewater treatment plant. |
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