Concentrated salt waste water composite zero discharge system and process

Abstract

The invention belongs to the technical field of water treatment and particularly relates to a concentrated salt waste water composite zero discharge system and a concentrated salt waste water composite zero discharge process. The concentrated salt waste water composite zero discharge process is characterized by comprising the following steps: (1) reducing the hardness of calcium and magnesium ionsof to-be-treated concentrated salt waste water; (2) performing softening treatment on the concentrated salt waste water; (3) performing twice membrane concentration crystallization treatment on the soft water part of the treated water; (4) performing evaporation crystallization treatment on the concentrated salt water subjected to the first-time membrane concentration crystallization treatment; and (5) performing spraying crystallization on concentrate salt slurry and recovering the crystal salt after spraying crystallization into smoke. The system and the process have the following beneficial effects: the system is low in energy consumption, low in system investment, reliable in operation, low in treatment cost and small in sewage quantity, the operation of the subsequent dust-removing equipment is not influenced, mixed salt products are not generated, the crystal salt does not need to be subjected to one-step treatment, and the operation stability of the whole system is guaranteed.

Description

(1) Technical field [0001] The invention belongs to the technical field of water treatment, in particular to a compound zero-discharge system and process for concentrated salt wastewater. (2) Background technology [0002] Pollution prevention and control technology policies for thermal power plants: water pollution prevention and control in thermal power plants should follow the principles of classified treatment and multiple uses of one water, and encourage thermal power plants to realize the recycling of wastewater without discharge; desulfurization wastewater should be treated with lime, flocculation, clarification, neutralization and other processes Reuse after treatment; encourage the use of flue gas waste heat evaporative drying or evaporative crystallization and other treatment processes to prevent desulfurization wastewater from being discharged outside. [0003] Feasible Technical Guidelines for Pollution Prevention and Control in Thermal Power Plants: In addition ...

AI Technical Summary

Problems solved by technology

If the fouling equipment cannot continue to be used, and the power consumption of the MVR process is high, the process investment is high, and the cost of wastewater treatment per ton is high, reaching 60 yuan / cubic meter

[0009] MED process (multi-effect forced circulation evaporation and crystallization process) has low investment, but the process has high steam consumption, high power consumption, high operating costs, and high cost per ton of wastewater treatment, exceeding 80 yuan / m3

[0010] Multi-stage membrane concentration technology process has high reliability, low energy consumption and low investment when the liquid concentration is low and the concentrated concentration is low. When the concentration exceeds 10%, the investment and operating costs will increase significantly, and the operating reliability will be reversed. dramatically drop

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