Landfill leachate treatment process

Abstract

The invention relates to a landfill leachate treatment process, which comprises the following steps of: performing catalytic oxidization pretreatment; performing primary biochemical treatment; performing advanced oxidization treatment; performing secondary biochemical treatment and multi-media filtration on effluent, so that the treated effluent can reach the standard in a table 2 of Standard for Pollution Control on the Landfill Site for Domestic Waste (GB16889-2008) and is discharged; and under special conditions (such as an environmentally sensitive area), allowing the effluent to enter an active carbon adsorption (active carbon adsorption also can serve as emergency measures) treatment system, so that the treated effluent can reach the standard in a table 3 of Standard for Pollution Control on the Landfill Site for Domestic Waste (GB16889-2008) and is discharged. The method has the advantages of short treatment time, good effect and low cost, is easy to continuously operate to realize scale treatment, and has a great application prospect.

Description

technical field [0001] The invention relates to a landfill leachate treatment process, in particular to a landfill leachate non-membrane treatment process. Background technique [0002] The composition of landfill leachate is extremely complex, containing a large amount of heavy metal ions and refractory organic matter. It is a kind of toxic and harmful high-concentration organic wastewater. Usually, the COD in winter is 30,000-50,000 mg / L or even higher, and in summer it is also 10,000-30,000 mg / L. ; The total nitrogen concentration is high, and the inorganic ammonia and organic ammonia produced by a large amount of domestic waste cause the total nitrogen content in the wastewater to reach 1000-3000mg / L; High chroma: the water quality is soy sauce-colored, turbid, and the sensory effect is extremely poor; the water quality and quantity fluctuate greatly : It is greatly affected by the climate, such as the rainy season, and the water quality and quantity fluctuate significan...

AI Technical Summary

Problems solved by technology

[0005] The existing treatment process mainly has the following problems: 1) Lack of influent pretreatment guarantee system, the operation of the biochemical system is vulnerable to the impact of toxic substances and high loads, and the nitrification and denitrification denitrification bacteria are relatively fragile and difficult to re-cultivate, affecting the stability of the effluent; 2 ) The MBR membrane is easy to clog, and neither the built-in nor the external membrane module can effectively solve the clogging problem, especially when the sludge properties are not good, the clogging will intensify and affect the normal operation; 3) MBR retains sludge while At the same time, a large number of biological metabolites or toxic substances are retained, resulting in the long-term accumulation of the above substances, and the COD of the effluent is relatively high, generally around 500-1000

In addition, there is a lot of biological foam, so a large amount of additional defoamer must be added, which increases the operating cost; 4) Many indicators of biochemical and conventional MBR effluent (including COD, total nitrogen, etc.) are still high, and the appearance of the drainage is brownish red, which cannot be achieved. It is more difficult to meet the direct discharge standards required by urban sewage treatment plants; 5) At present, large-scale landfill leachate treatment plants use R / O as an advanced treatment process, but the COD of R / O influent water is as high as several hundred, containing a large amount of pollution that cannot be metabolized by organisms Substances and biochemical metabolites are directly processed by R / O membrane (or nanofiltration) (the removal rate of these substances by the security unit before R / O and nanofiltration is very limited), which intensifies the load on the membrane module, and the membrane is easy to clog and needs to be replaced. High frequency; 6) Waste water has high salinity, and R / O and nanofiltration membrane modules after biochemical effluent need to use high-pressure salt-resistant and fouling-resistant membranes, the investment and operation costs are huge, and the cost per ton of water treatment is more than tens of yuan

7) R / O (or nanofiltration) concentrated water is difficult to treat and has high salinity. Due to limited conditions, most sewage plants can only refill concentrated water into landfills, resulting in long-term accumulation of salt in the leachate treatment system In the process, it seriously increases the difficulty of subsequent treatment of leachate

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