混凝-气浮预处理垃圾渗滤液的模拟试验研究

Simulation test on pretreating landfill leachate with coagulation and flotation

为了降低垃圾渗滤液中有机物和悬浮物含量,减轻后续处理负担,采用混凝—气浮工艺对垃圾渗滤液进行预处理,并考察其影响因素。结果表明,混凝剂种类、用量、混凝pH值、气浮作用时间等因素对有机物的去除率有明显影响。在优化工艺条件下,当进水COD为5600mg·L-1时,COD去除率可达到81.9%,BOD5的去除率可达73.3%,BOD5/COD从0.26提高到了0.40,有效提高了渗滤液的可生化性。研究表明,混凝—气浮工艺流程达到了较好的预处理效果。

The present paper intends to introduce the author＇ s renovation of a pretreatment method of landfill leaehate by coagulation and flotation technology. For the research purpose, the authors have done simulated experiments with the leaehate from Laohuehong landfill in Shenyang, Liaoning. The analysis results of the wastewater quality prove that the landfill leaehate is a kind of wastewater with strong odor pollution laden with a high organic matter and hard biodegradation. Traditionally, it is believed that biochemical processing and other treatment technologies, such as ultraviolet oxidation and land treatment are effective methods. However, for the high construction expenditure and operational cost, large quantity of leaheate remains problematic due to its cost. Thus, it becomes necessary to adopt appropriate pretreatment so as to remove the organic and suspended matter at least partly, relieve and reassure the operation of the treat- ment course afterwards so as to reduce the capital investment, It is for this reason, this study has taken several parameters of the coagulation and flotation in its experiments so as to optimize the organic matter removal. The results of our experiments demonstrate that the types of coagulants, dosage, pH and flotation time are all the significant factors. The optimum operational condition should be coagulant PAC 700 mg·L^- 1, PAM 3.0 mg·L^-1, precipitation time 30min, coagulation pH 6.0, flotation agent dosage 333 mg·L^-1, flotation time 10 min. Under such conditions, the treatment effect of COD and BOD5 can reach 81.9% and 73.3%, respectively, and the value of BOD5/COD can be expected to increase from 0.26 to 0.40, which makes the leachate easier to biodegrade. Furthermore, the treated effluent with the given method can be made to come up to the standard for pollution control on the landfill site for domestic waste （GB 16889- 1997）, whereas the removal effects of this system prove stable and. less affected by the outside environment. Thus, coagulation and flotation process proves of great value for the pretreatment of landfill treatment.