Pretreatment desalting method for landfill leachate

Abstract

The invention relates to the field of leachate treatment, especially to a pretreatment desalting method for landfill leachate. Equipment used in the invention comprises an adjusting tank, an adjustable electric flocculation-electrolysis-air floatation-sedimentation integrated tank, an effluent collecting tank, a first conductivity online measuring instrument, a power supply device and a PLC electric control device. The pretreatment desalination method for landfill leachate provided by the invention has the advantages of no addition of chemicals, reduction of salt content, reduction of the burden of subsequent biochemical treatment or membrane treatment processes, high automation degree, low energy consumption and low sludge yield.

Description

technical field [0001] The invention relates to the field of leachate treatment, in particular to a method for pretreatment and desalination of landfill leachate. Background technique [0002] The water quality of landfill leachate has the characteristics of high COD, high ammonia nitrogen, high salt concentration, high stench, high chroma, and contains a variety of bacteria, germs and heavy metals. Effective treatment will discharge into the environment, which will seriously pollute surface water and groundwater. Once the groundwater is polluted, the environment of the polluted area will be difficult to recover, bringing long-term environmental disasters to the polluted area. The water quality characteristics of landfill leachate determine that landfill leachate is very difficult to treat wastewater. If any water quality characteristic factors are ignored in the design of landfill leachate treatment system, it will eventually affect the treatment effect, resulting in the wa...

AI Technical Summary

Problems solved by technology

However, this pretreatment process increases the salinity in the water due to the addition of a large amount of chemicals, and the increase in salinity has a significant inhibitory effect on the subsequent biochemical treatment unit, making it difficult for microorganisms in the biochemical system to grow and reproduce, and the proliferation rate is slow, especially for old landfill leachate. It can even easily lead to the collapse of the biochemical system; and the pressure of the subsequent membrane filtration system increases, the probability of clogging increases, the frequency of cleaning increases, the life of the membrane decreases, and the cost of operation and maintenance increases significantly

[0004] The Fenton advanced oxidation process also has the same disadvantages as the above-mentioned process, because the Fenton process relies on adding a large amount of oxidant and catalyst to oxidize organic matter, but the salt content is also greatly increased to produce the same consequences as the above-mentioned patent process

[0005] The traditional electrolysis process used for the pretreatment of landfill leachate focuses on the electrolysis reaction to generate atomic oxygen to oxidize organic matter, which can remove COD, but traditional electrolysis also exists to oxidize and reduce organic matter and inorganic matter in leachate Decomposition, so that the conductivity or salinity will not drop but rise, which will increase the salinity in the later stage and increase the difficulty of biological treatment or membrane filtration

[0006] The traditional electrocoagulation process used for the pretreatment of landfill leachate mainly produces a large amount of flocs by sacrificing the anode plate and traps colloidal pollutants. Mud, and after the anode plate is dissolved in excess, it is the same as overdosing. If the purpose is only to remove organic matter and suspended matter, the ionic state of the anode dissolved in the water will be excessive, which will also cause an increase in salt in the water.

These are not considered for the traditional electrocoagulation process, or are unavoidable, or cannot be strictly controlled

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