Research On Toxicity Inhibition Of Landfill Leachate On Anaerobic Sludge

Municipal landfill leachate, come from the municipal solid wastes(MSW) treatment, contained kinds of pathogeny microorganism and certain substance causing cancer, which is very harmful for the environment.Anaerobic Processing is a sort of low cost and common technology which treats the disposal of wastewater with high concentration. Anaerobic Processing possesses of low energy consumption, convenient operation, low invest and running cost, and accompanied organic degradation with produce gaseous fuel. As a result it is developed broadly and applied. Landfill leachate is a kind of complex organic wastewater with high concentration, and is difficulty treated, which has a inhibition on anaerobic microorganism and creates a hazard in anaerobic processing. So studying and improving the treatment technology of domestic landfill leachate is a important task in the water treatment field today.In this thesis, anaerobic toxicity of landfill leachate is researched by Anaerobic Toxicity Assay (ATA). And UASB was selected as a major object studied and was experimentized analogly in laboratory. The results as follows:1) Atom absorption spectrophotometer and gas chromatograph-mass spectrometer method(GC-MS) were used to measure the concentration of heavy metals and organic pollutants in the landfill leachate. In this kind of landfill leachate, 44 kinds of organic pollutants been discovered were more than 60% in reliability, and As,Pb,Cr and Ni is above 0.1mg/L in the landfill leachate.2) Heavy metal salt, organic and ammonia nitrogen of the leachate that is typical characters of "aging" leachate were study. The results of the experiment showed that the "aging" leachate made the activity decreased 55.5% and the period of most biogas production time delayed 14d. while fresh leachate made the activity of anaerobic sludge been in restrained state in the days of trial, the half lethal dose of heavy metal salt, organic and ammonia nitrogen to anaerobic microorganism is 2.9 times of the content of heavy metal salt of the "aging" leachate, 3.2 times of the content of organic of the "aging" leachate, and 2.3g/L ammonia nitrogen in concentration.3) Compared non-pretreatment leachate with the leachate deposited and blow-off in the basicity with which to act as feed-water of UASB, we found that pretreatment deposited and blow-off in the basicity was of great advantage to anaerobic processing, which the rate of COD removal reached 60 percent. When the load of the leachate by pretreatment reach 5kgCOD/m3·d, the rate of COD removal maintain 50 percent the above.4) Landfill leachate varied relatively large with natural degradation in the course of deposit. The affect of toxicity of leachate for anaerobic microorganism was an important problem need to take into account for fresh leachate. With natural degradation the COD and the biodegradability reduced obviously, and the leachate presented the character of "aging". But the low biodegradability will turn into the difficulty of anaerobic processing.