Concentrated leachate treatment system and method

Abstract

The invention relates to a concentrated leachate treatment system. The system comprises a membrane biological reaction mechanism, an HPRO treatment unit and a low-temperature negative-pressure evaporation device, wherein a water production pipeline of the membrane biological reaction mechanism is connected with a water inlet of the HPRO treatment unit, a concentrated solution outlet pipe of the HPRO treatment unit is connected to the low-temperature negative-pressure evaporation device, and a clear liquid outlet pipe of the HPRO treatment unit is connected with a clear liquid treatment mechanism. Correspondingly, the invention further provides a concentrated leachate treatment method. The membrane biological reaction mechanism and the HPRO treatment unit are adopted to ensure the treatment effect on the concentrated leachate, and the low-temperature negative-pressure evaporation device is adopted to treat an HPRO concentrated solution, so salt precipitation and heat exchange surface scaling caused by heat exchange surface evaporation are avoided, a higher concentration ratio and longer operation cycle can be realized, salty mud crystallization can be realized, the final product only generates stably solidified salty mud, full-quantitative treatment is realized, and secondary pollution is avoided.

Description

technical field [0001] The invention belongs to the technical field of landfill leachate treatment, and in particular relates to a leachate concentrate treatment system and treatment method. Background technique [0002] The landfill leachate membrane filtration concentrate is the residual liquid intercepted by the RO membrane (or NF membrane) after the landfill leachate undergoes biodegradation. The separation principle of nanofiltration and reverse osmosis is: due to the selective permeability of the osmotic membrane, water can pass through the membrane smoothly, while other compounds are more or less or even completely intercepted by the membrane, so that the influent water is divided into treated permeate after passing through the membrane. Liquid and retentate (concentrate) in two parts. The concentrate is generally not biodegradable, the main component is humic substances, brownish black, high COD (usually above 5000mg / L), and contains a large amount of metal ions, TD...

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Problems solved by technology

[0004] Although the leachate concentrate recharge technology can promote the degradation of degradable organic matter, it will also lead to the enrichment of effluent COD, conductivity, ammonium ion and chloride ion, and cause secondary pollution of groundwater

[0005] The reduction treatment is mainly based on membrane technology and traditional evaporation technology. Because the concentrated solution contains high concentrations of humic acid and fulvic acid, it will cause irreversible membrane fouling; in addition, the high hardness of the concentrated solution can easily cause Scaling seriously affects membrane treatment efficiency

At present, traditional evaporation technologies that have been applied in the treatment of landfill leachate concentrate include single-effect evaporation, multi-effect evaporation and MVR evaporation, etc., but at the operating temperature of the above-mentioned evaporation technologies, the enriched chloride ions in the concentrate will Severe corrosion occurs, and at the same time, the high concentration of humus and inorganic salt ions in the concentrated solution can easily lead to serious fouling of equipment, reduce heat transfer efficiency and evaporation energy efficiency ratio, and reduce operation stability

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