Process and device for autotrophic biological denitrification of urban secondary effluent

Abstract

The invention discloses a process for autotrophic biological denitrification of urban secondary effluent. The process specifically comprises the following steps: dissolving pyrite in a pyrite dissolving tank, feeding the dissolved pyrite and urban secondary effluent to be treated into a biological membrane denitrification tank, and carrying out autotrophic biological denitrification and synergistic phosphorus removal. Pyrite and biological nitrogen removal are separated, an acid is added into the pyrite dissolving tank to promote dissolution of pyrite and improve the solubility of pyrite, ferrous ions, elemental sulfur and sulfur ions which can serve as electron donors are generated at the same time, rapid growth of sulfur autotrophic microorganisms is achieved, and the nitrogen and phosphorus removal efficiency is improved; and the dosage of the pyrite is adjusted through a flow adjuster and is added according to the nutrient proportion requirement of the autotrophic denitrification microorganisms, and waste of the pyrite is reduced. The process overcomes the defects of low solubility of pyrite, low denitrification rate and difficulty in controlling the proportion of the nutrientmedium in the denitrification process in the traditional autotrophic denitrification system, enhances the nitrogen and phosphorus removal speed, and shortens the hydraulic retention time of a reactionzone.

Description

technical field [0001] The invention belongs to the technical field of wastewater treatment, and in particular relates to a sulfur autotrophic denitrification and chemical phosphorus removal method aimed at deep denitrification and phosphorus removal of urban secondary effluent. Background technique [0002] In order to alleviate the harm caused by the eutrophication of water bodies, the discharge standards of urban sewage have become increasingly strict. At present, some places in China, such as Beijing, Shanghai, Tianjin, Zhejiang and other places have implemented relatively strict local discharge standards, and some indicators (nitrogen, phosphorus) are close to the third or fourth standards of surface water bodies. Therefore, the nitrogen and phosphorus in the urban secondary effluent must be deeply denitrified and dephosphorized. The traditional method of phosphorus removal by adding chemical phosphorus removal agents and biological nitrogen removal by adding organic c...

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Problems solved by technology

[0004] As an electron donor for autotrophic denitrification, pyrite has the advantages of long life, high nitrate removal rate, and low price, but its reaction has low solubility of pyrite, long reaction time, large reactor volume, and denitrification The proportion of nutrient matrix in the process is not easy to control, which brings many difficulties to practical application

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