Method for extracting humic acid from landfill leachate

Abstract

The invention relates to a method for extracting humic acid from landfill leachate. The method comprises the following steps: 1, allowing landfill leachate to sequentially pass through an anaerobic reactor (UASB), a reaction tank (SBR), a continuous microfiltration system (CMF) and a reverse osmosis membrane (RO), and carrying out combined treatment to obtain a reverse osmosis concentrated solution; 2, adjusting the pH value of the concentrated solution to 6-6.5, pumping the concentrated solution into a primary ultrafiltration system, removing calcium and magnesium ions from an obtained primary ultrafiltration trapped fluid by using a precipitant, and pumping the primary ultrafiltration trapped fluid into a secondary ultrafiltration system to obtain a secondary ultrafiltration trapped fluid; 3, drying activated sludge from a municipal sewage treatment plant, and pulverizing the activated sludge by a pulverizer to obtain activated sludge powder; 4, adding Na2S into the activated sludgepowder, carrying out uniform mixing, adding the obtained mixture into the secondary ultrafiltration trapped fluid prepared in the step 2, and conducting precipitating; and 5, adding calcium chloride and polymerized aluminum oxide into the mixture obtained in the step 4, and then conveying intercepted liquid into a cyclone device for sludge recovery so as to obtain a liquid which is a heavy metal-recovered humic acid solution.

Description

technical field [0001] The invention belongs to the technical field of landfill leachate treatment, in particular to a method for extracting humic acid from landfill leachate. Background technique [0002] With the gradual advancement of industrialization and urbanization, China's urban waste will increase at a rate of 9%-10% per year. Municipal waste treatment methods mainly include sanitary landfill, composting, incineration for power generation, pyrolysis, etc. At present, my country's urban waste is mainly disposed of by sanitary landfill or incineration. However, during the process of sanitary landfill, domestic waste will produce a large amount of landfill leachate through anaerobic fermentation, degradation and rainwater washing. In addition, in the process of burning garbage, leachate with a volume of 5%-28% of the garbage disposal volume will also be produced. The water quality of garbage seepage liquid has the characteristics of complex composition, large changes...

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Problems solved by technology

[0004] At present, the membrane extraction technology of humic acid in membrane concentrate mainly adopts the ultrafiltration membrane with a molecular weight cut-off of 1000 Da. Although it has a good interception effect on humic acid, it will also enrich divalent ions, especially in the secondary ultrafiltration During the filtration process, the concentration of divalent ions increases faster, which affects the product quality and the stability of the membrane system. At the same time, divalent ions will have a significant impact on the surface charge of the membrane. 2+ , Mg2 + It will neutralize the negative charge on the surface of the membrane, reduce the electrostatic repulsion of the membrane to humic acid molecules, so that more humic acid molecules can be adsorbed on the membrane; in addition, divalent cations will also increase the size of humic acid colloids, and Salt bridges are formed between the membrane and humic acid, which accelerates the deposition of humic acid on the membrane surface and aggravates membrane fouling

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