Method for removing passivation film mainly containing Fe2O3.FeO in biological sponge iron surface layer

Abstract

The invention relates to a method for removing a passivation film mainly containing Fe2O3.FeO in a biological sponge iron surface layer, belonging to the technical field of industrial wastewater treatment. The method disclosed by the invention comprises the following steps that: an organic porous carrier and biological sponge iron with the volume ratio of 3:1 are fed in a reactor; aeration is carried out continuously; the dissolved oxygen is controlled within 2-3 mg / l; inflow water in the reactor is outflow water of a septic tank; the hydraulic counter-current operation retention time in the reactor is controlled for 8 h; TP change of the inflow water and the outflow water is monitored simultaneously; when the concentration of the outflow water TP of the reactor is beyond 1 mg / l, an aeration device in the reactor is closed, so that the reactor is in an anerobic state; when a biological sponge carrier in the reactor is in a submerging state, the inflow water in the biological sponge iron reactor for generating sponge ion passivation is reduced for 5 d continuously or closed for 3 d continuously; operation of the reactor is stopped; the reactor begins to inflow water, aerate and operate; and the above processes are repeated for one time. The method disclosed by the invention is simple and convenient to operate, lower in cost and high in operation treatment effect.

Description

technical field [0001] The invention belongs to the technical field of industrial wastewater treatment, in particular to a method for removing the surface layer of biological sponge iron with Fe 2 o 3 · FeO-based passivation film method. Background technique [0002] Sponge iron is made of pure iron and Fe 3 The alloy composed of C and some impurities has the characteristics of high iron content, porous light weight, and easy processing and use. Iron and Fe in the sponge 3 C and other impurities can form a corrosive primary battery in the electrolyte solution. In a neutral or slightly acidic environment, chemical corrosion will occur, and Fe will be generated through electrode reaction. 2+ . Under the condition of microbial participation, the electrochemical corrosion rate of sponge iron will be accelerated. Fe produced during this process 2+ It also stimulates the growth of iron-oxidizing bacteria. Iron oxidizing bacteria and Fe 2+ During the reaction, a strong oxi...

AI Technical Summary

Problems solved by technology

[0005] The easiest way to eliminate the passivation film on the surface of biological sponge iron is to take out the biological sponge iron and remove it mechanically, but this method is too labor-intensive and the effect is not good, so it cannot be applied in the actual process; cleaning with acid The effect is feasible, but it will destroy the activity of microorganisms