Pretreatment method suitable for evaporative crystallization of landfill leachate stock solution

Abstract

The invention provides a pretreatment method suitable for evaporative crystallization of a landfill leachate stock solution and relates to the field of sewage treatment.The method includes the following steps that 1, the landfill leachate stock solution is fed into a rapid stirring pond, inorganic coagulant and a backflow centrifugal clear solution are added into the rapid stirring pond according to the mass ratio, rapid stirring is conducted, and then the coagulant is rapidly dispersed and mixed to be uniform; 2, after treatment in the step 1, organic coagulant is added into a slow stirring pond according to the mass ratio; 3, landfill leachate treated in the step 2 is fed into a centrifugal dehydrator, a centrifugal clear solution part serves as diluent to flow back to the rapid stirring pond, and the remaining part enters a follow-up landfill leachate evaporative crystallization system.Dilution, flocculation and centrifugation are combined together for the first time, the procedures are simple, the period is short, adaptability is high, the effect is stable, the pretreatment method is successfully applied to pretreatment of evaporative crystallization of the landfill leachate stock solution, and the problems that according to a conventional flocculent settling pretreatment process, the agent adding amount is large, settling efficiency is low, and the turbidity removal effect is not ideal.

Description

technical field [0001] The invention relates to the field of sewage treatment, in particular to a pretreatment method suitable for evaporation and crystallization of raw liquid of landfill leachate. Background technique [0002] The composition of landfill leachate is very complex, and it has the characteristics of large fluctuations in water quality and quantity, high pollutant content, and imbalance of nutrient elements, making it difficult to meet the standards and high operating costs. Therefore, the pollution control of landfill leachate has always been a thorny issue in domestic and foreign urban waste management systems. In particular, in 2008, my country promulgated and implemented the "Standards for Pollution Control of Domestic Garbage Landfill Sites" (GB16889-2008), which has stricter requirements on the discharge of landfill leachate. [0003] At present, domestic landfill leachate treatment manufacturers mainly adopt the "pretreatment + biochemical + membrane" ...

AI Technical Summary

Problems solved by technology

However, the SS in the landfill leachate stock solution is about 2000~15000mg / L, and the turbidity is as high as 2000~8000NTU. The direct evaporation of such a high suspended solids and high turbidity leachate without pretreatment will lead to heat exchanger blockage and evaporator knot. The frequent occurrence of scale and other phenomena seriously affects the efficient and stable operation of the evaporation system

The author's research shows that it is difficult to achieve the ideal turbidity removal effect by the conventional coagulation and sedimentation method, even if the dosage of the agent is as high as 20g / L and the sedimentation time is as long as 1h, the reasons are due to the high turbidity, sludge production and difficult sedimentation

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