Reverse-osmosis strong brine treatment device and method for cold rolling wastewater

Abstract

The invention discloses a reverse-osmosis strong brine treatment device and method for cold rolling wastewater. The device comprises a resin adsorption column, an activated carbon adsorption-regeneration device, a resin regeneration liquid storage tank and a resin desorption liquid storage tank. According to the reverse-osmosis strong brine treatment device and method, selective ion exchange resinis used for adsorbing to remove nitrate in wastewater; granular coconut shell activated carbon is used for adsorbing to remove organic matters in the wastewater. Desorption liquid generated by regenerating nitrate adsorption resin is used as an electrolyte solution for electrochemical regeneration of the activated carbon, and the nitrate in the desorption liquid is removed in an electrochemical regeneration process of the activated carbon; the desorption liquid can be used as resin regeneration liquid to be repeatedly utilized. According to the device and method, disclosed by the invention, COD (Chemical Oxygen Demand) and total nitrogen of output water can meet the requirements of emission standards and are not influenced by factors including high salt content, high hardness and the likein strong brine.

Description

technical field [0001] The invention relates to the technical field of wastewater treatment, in particular to a cold rolling wastewater reverse osmosis concentrated brine treatment device and method. Background technique [0002] Iron and steel cold rolling wastewater mainly includes acid wastewater, concentrated alkali and emulsion wastewater, dilute alkali oily wastewater and leveling liquor wastewater, which is a type of wastewater that is difficult to treat in the iron and steel industry. At present, under the background of the country's requirement of "energy saving and emission reduction" in various industries, the use of reverse osmosis technology for advanced treatment and reuse of cold rolling wastewater has been more and more engineering applications. The recovery rate of the reverse osmosis recycling process is usually 70%~75%, that is, after the cold rolling wastewater is treated by reverse osmosis, it will produce recycled water accounting for 70%~75% of the ori...

AI Technical Summary

Problems solved by technology

This method has the following problems: (1) The use of biological methods to degrade total nitrogen needs to consume carbon sources that are easily utilized by denitrifying microorganisms. Since the organic matter in the cold-rolled reverse osmosis concentrated brine has poor biodegradability and is not easily degraded and utilized by microorganisms, additional Dosing methanol or glucose and other substances makes the operation cost of concentrated brine treatment higher; moreover, the denitrification and denitrification process has high requirements for carbon source dosing control. When the supply is insufficient, nitrite will accumulate, and when the dosing is excessive, it will lead to COD in the effluent. raised

(2) The biological treatment method is greatly affected by the water temperature, and the operation effect is poor when the water temperature is low in winter

(3) The biological treatment method is greatly affected by the salt content of the influent. When the salt content of the influent is too high, it will inhibit the microbial activity and affect the removal effect of COD and total nitrogen.

The problems of this method are: (1) Due to the interference of ions in the high-salt reverse osmosis concentrated brine, the organic matter is easily decomposed during the resin adsorption process, so that the resin adsorption COD removal rate is not high and the adsorption capacity of the resin to organic matter is low.

(2) The desorption solution containing high concentration of COD produced during resin regeneration is difficult to properly handle

The problems of this method are: (1) The nitrate in the resin desorption solution is returned to the front-end biochemical treatment system for removal. When the carbon source in the original wastewater is insufficient, additional carbon sources required for denitrification and denitrification need to be added ; (2) A large amount of sodium chloride is required for each regeneration of the resin, that is, the high concentration of sodium chloride in the regeneration desorption solution has not been reused, which makes the operating cost higher

[0006] To sum up, there are problems such as the need to add additional carbon sources to the reverse osmosis concentrated brine of cold rolling wastewater treated by the biological method, and being easily affected by the high salt content in the concentrated brine; while the resin method for the treatment of cold rolling wastewater reverse osmosis concentrated brine has regeneration Difficult to deal with attached liquid, difficult to reuse regenerative agents, etc.

Images