Treatment method for nanofiltration concentrated liquor of landfill leachate

Abstract

The invention relates to a treatment method for nanofiltration concentrated liquor of landfill leachate, which comprises the following steps: carrying out medium-pressure nanofiltration treatment first for minimization, carrying out coagulation air floatation treatment for the concentrated liquor after the medium-pressure nanofiltration treatment to recycle humous larger molecular organics for resource utilization, carrying out resin-based softening treatment to reduce the hardness of the concentrated liquor after the coagulation air floatation treatment, performing electrolytic oxidation treatment on the concentrated liquor after the resin-based softening treatment and treating back washing water, feeding the clear liquid from the medium-pressure nanofiltration, yielding water from the regenerated waste liquor and yielding water after the electrolytic oxidation to membrane bioreaction treatment, performing tail gas absorption treatment on gases generated from the electrolytic oxidation, and absorbing chlorine gas in tail gases before up-to-standard emission. The treatment method for nanofiltration concentrated liquor of landfill leachate is reasonable in treatment process with a good treatment effect, and relatively low in investment and operation costs; the problem of accumulation of humic acids and hardness ions in the biochemical system is avoided, and the difficulty in treating the nanofiltration concentrated liquor of the landfill leachate is solved; and the treatment method is applicable to treating the nanofiltration concentrated liquor generated in the 'MBR+nanofiltration' treatment process for the landfill leachate.

Description

technical field [0001] The invention relates to a method for treating landfill leachate nanofiltration concentrated liquid, and belongs to the technical field of waste water treatment. Background technique [0002] For landfill leachate treatment, the "Technical Specifications for Landfill Leachate Treatment Engineering" issued by the Ministry of Environmental Protection recommends the combined process of "pretreatment + biological treatment + advanced treatment". After biological treatment, landfill leachate needs to be further treated by nanofiltration membrane or reverse osmosis membrane to meet the discharge standard. The concentrated liquid produced by the membrane unit is relatively large, accounting for about 20% of the volume of landfill leachate. The concentrated liquid of membrane filtration has the characteristics of high organic concentration, high salinity, and poor biodegradability. [0003] In the landfill leachate treatment project, nanofiltration is mainly ...

AI Technical Summary

Problems solved by technology

The recharge method will cause the gradual accumulation of organic matter and salt in the landfill, but when the high-concentration and high-salt leachate returns to the membrane bioreactor (MBR) for degradation, it will cause the pressure of the membrane tube to rise, the system operation is extremely unstable, and the treatment effect will decline

Patent documents CN1923875A, CN103964609 A and CN 103626314A all adopt the membrane concentration method to process the nanofiltration concentrate, but the membrane concentration method has problems such as high operating pressure, high energy consumption, low water production rate, and serious membrane pollution, and the membrane filtration concentrate still need to be processed, which increases the cost of processing

Patent documents CN103570157A and CN104211245A use the evaporation method to treat the nanofiltration concentrate, but this method has high investment and high energy consumption, and the evaporation residue is hazardous waste, and the disposal cost is high

Both patent documents CN101701025A and CN104478157 A use the coagulation precipitation-advanced oxidation method to treat the nanofiltration concentrated liquid. This method has a good effect on the removal of humic acid substances, but the residual organic nitrogen in the concentrated liquid will be oxidized to nitrate nitrogen , the total nitrogen in the effluent is difficult to reach the standard

The patent document CN102701515A adopts the electrochemical oxidation method to treat the nanofiltration concentrated liquid. This method does not remove the hardness ions in the nanofiltration concentrated liquid. Long-term operation will cause fouling and blockage of the electrolytic plates, pipelines and reactors.

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