Method for realizing approximate zero discharge of high-fluorine-content and high-nitrogen-content battery production waste water in photovoltaic industry

Abstract

The invention discloses a method for realizing approximate zero discharge of high-fluorine-content and high-nitrogen-content battery production waste water in the photovoltaic industry. The method comprises the following steps: feeding high-fluorine-content and high-nitrogen-content battery production waste water into a regulating tank for homogenizing; feeding into a fluorine-removing reaction tank, and feeding a reaction tank effluent into a sedimentation tank; feeding a supernatant in the sedimentation tank into a middle water tank; treating by virtue of a quartz sand filter and an active carbon filter, and feeding fresh water into a primary reverse osmosis membrane for treating; driving reverse osmosis membrane concentrated water to flow through a concentrated water induced acceleration crystallizing pond to precipitate calcium ions and fluorine ions in concentrated water on a seed crystal at a higher speed, effectively lower the concentrations of calcium ions and fluorine ions and increase the concentration multiple of a reverse osmosis concentration membrane, driving supernatant to flow through a cartridge filter, and feeding into the reverse osmosis concentration membrane for circularly concentrating; feeding a small amount of concentrated water on the reverse osmosis concentration membrane into an evaporator to greatly lower the evaporation cost, feeding steam condensed water into a recycling water tank for use as industrial water, and disposing evaporation residues as solid waste. In the entire process, no water pollutant is discharged.

Description

technical field [0001] The invention belongs to the field of sewage treatment engineering, and relates to a method for defluorination, denitrification and reuse of high-fluorine and nitrogen-containing waste water in the photovoltaic industry, and realizes zero discharge. Background technique [0002] my country is one of the countries with the poorest per capita water resources in the world. While the development of the industrial economy has created huge wealth, it has also put enormous pressure on the local resources and environment. The pollution of the water environment is particularly serious. There is an urgent need to develop advanced treatment and reuse technologies for industrial wastewater. Although solar photovoltaic energy is green energy, there is still serious water pollution in the production process of photovoltaic cells. Different sections of photovoltaic cell production are generally undertaken by different companies, and the discharges are mainly polysil...

AI Technical Summary

Problems solved by technology

However, there are still many key technical problems in the reverse osmosis process. First, the excess calcium ions brought by the previous defluoridation process will cause serious pollution to the reverse osmosis membrane. Membrane fouling will make it difficult for the membrane equipment to operate normally. Concentration is difficult, among which reducing the concentration of fluoride ions and calcium ions in wastewater that easily cause membrane fouling is the key, and membrane fouling is a key factor affecting the promotion of reverse osmosis membrane technology; the second is that even if the wastewater recovery rate of 70% is achieved , still 30% of the waste water needs to be evaporated

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