Method for recycling high concentration ammonia nitrogen and making ammonia nitrogen into large granule high purity struvite

Abstract

The invention relates to a method for recycling high concentration ammonia nitrogen and making ammonia nitrogen into large granule high purity struvite. At first, a granulating main body is changed to a three-section tapered fluidized bed reactor. The reactor is composed of a feeding tube, a granulating tube, and a sediment tube; the connection part between the sediment tube and the granulating tube is in a truncated cone shape, the inclined angel theta of the generatrix of the connection part is 25 degree to 45 degree; the ratio of the external diameter of the big end of the granulating tube to the external diameter of the small end of the granulating tube is equal to 3:1; the ratio of the length of the granulating tube to the external diameter of the small end of the granulating tube is equal to 50:1; a pH probe is arranged in the granulating tube, the bottom of the granulating tube and the top of the feeding tube are both provided with a granulating tube valve; the bottom of the feeding pipe which is provided with five material inlets is provided with a discharging valve; and the length ratio of the sediment tube to the granulating tube to the feeding tube is equal to 2:5:1. High concentration nitrogen-phosphor wastewater with a NH4<+>-N concentration of 1000 to 1600 mg / L and a magnesium chloride solution are simultaneously pumped into the granulating main body, at the same time the mole ratio of NH4<+>-N: PO4<3>-P:Mg<2+> is controlled at 1.5:1:1.1-1.5:1:1.3, the pH value is controlled at 6 to 7, the reflux ratio is controlled at 12 to 30, the diameter of the formed struvite particle is in a range of 3 to 8 mm, the purity of the struvite particle can reach 97.5% or more, and the hardness of the struvite particle is (20.3 + / - 1) kg / mm2. The method can used to prepare struvite from high concentration ammonia nitrogen industrial and poultry culture wastewater, garbage leachate, or sludge fermentation broth.

Description

technical field [0001] The invention relates to a method for recovering high-concentration ammonia nitrogen in sewage into high-purity large-particle struvite, and belongs to the technical field of waste water treatment and its resource utilization. Background technique [0002] With the development of industrial and agricultural production and the improvement of people's living standards, the discharge of ammonia nitrogen pollutants in my country has increased sharply. The discharge of ammonia nitrogen in sewage can easily lead to eutrophication of water bodies, resulting in the proliferation of algae and the death of fish, which has a serious impact on the ecological environment and has a huge impact on human life. However, ammonia nitrogen is a nutrient substance, and life on earth is inseparable from nitrogen. Therefore, from the dual purpose of water eutrophication control and sustainable utilization of ammonia nitrogen resources, the treatment method of high concentra...

AI Technical Summary

Problems solved by technology

Although the method of Chinese patent application 200480041593.0 "fluidized bed wastewater treatment" can also generate granular struvite, the fluidized bed reactor of this device includes four sections 15A, 15B, 15C, and 15D that are basically vertical, and each section is horizontal. The cross-sectional area increases in steps, and the hydraulic loss is large; the crystal residence time is at least four days, or even longer, and the nitrogen and phosphorus removal efficiency and the unit time efficiency of struvite growth are low; the removable PO 4 3- The concentration is 50-200mg / L, and it can only treat wastewater with medium and low phosphorus concentrations

[0005] The Chinese patent application 201210454919.9 "Apparatus and process for making struvite crystals from nitrogen and phosphorus in sewage" is similar to the above-mentioned patent. The fluidized bed reactor consists of four sections: feed pipe, crystal collection pipe, growth pipe and sedimentation pipe Composition, the bottom of the sedimentation tube is fixedly connected to the top of the growth tube, and the diameter of the sedimentation tube is twice the diameter of the growth tube, so the channel at the junction of the sedimentation tube and the growth tube suddenly increases, resulting in large hydraulic loss and the generation of particles Disadvantages of loose structure, low hardness, and easy breakage (please see the scanning electron microscope image of the particles); the concentration of ammonia nitrogen in the wastewater that can be treated is ≤1000mg / L, and the concentration of phosphate is <2200mg / L, and it is impossible to recycle higher concentrations of nitrogen and phosphorus wastewater

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