Device and process for recycling high-hardness nitrate wastewater

Abstract

The invention discloses a device and a process for recycling high-hardness nitrate wastewater. The device comprises a denitrification pulse pool, a calcium mud separation pool, a biochemical pool andan MBR membrane pool, wherein the denitrification pulse pool is a composite pool type of plug flow and complete mixing, the denitrification pulse pool comprises a first-stage denitrification pulse pool and a second-stage denitrification pulse pool, the calcium sludge separation tank comprises a first-stage calcium sludge separation tank and a second-stage calcium sludge separation tank, the calcium sludge separation tank comprises a central water distribution area, a middle separation area and a bottom concentration area, and the calcium sludge separation tank is provided with a water inlet area, a separation area, a concentration area and an automatic sludge discharge control device; a denitrification and decalcification system is arranged in front of the biochemical pool, and an MBR biological membrane system is arranged after the biochemical pool; and the MBR membrane tank is a reuse treatment device after aerobic biochemical treatment. According to the invention, activity reductioncaused by calcification of the activated sludge can be avoided, the calcium carbonate hardness of the wastewater is reduced while denitrification is performed, the pollutant removal efficiency is high, and good environmental protection and economic benefits are achieved.

Description

technical field [0001] The invention relates to a biochemical treatment improvement and recycling process for fluorine-containing wastewater in the solar cell industry, and belongs to the fields of wastewater treatment and water resource recycling. Background technique [0002] In the acid-base etching production process of the solar cell industry, a large amount of acid-base wastewater will be produced. The pollutants in the wastewater are mainly hydrofluoric acid, fluorosilicic acid, nitric acid, etc. The fluorine content of the wastewater is as high as 2000mg / L or more, and the total nitrogen is generally about It is 400-600mg / L. The common treatment process is calcium fluoride precipitation method. The dosing agent is milk of lime and calcium chloride. The fluoride ion is removed through two-stage coagulation reaction precipitation, and the removal of total nitrogen adopts biochemical denitrification process. . [0003] The main problems existing in the existing process...

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Problems solved by technology

[0003] The main problems existing in the existing process are: the high hardness nitrate wastewater after defluoridation has high calcium hardness, the biochemical sludge is prone to calcification, and the denitrification efficiency is low, which leads to the instability or even paralysis of the biochemical system, and the high hardness wastewater will Cause scaling or clogging of recycling process equipment, deep recycling treatment is difficult, and maintenance costs are high

[0006] The chemical precipitation method needs to add chemicals; the investment cost of membrane method and adsorption method is high, and the consumables need to be replaced regularly, which is only suitable for small water volume occasions; the structure of ion exchange, electrodialysis and other process equipment is complex, and the operation and maintenance are difficult. Improper will cause secondary pollution

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