Study on influence factors of treating landfill leachate by ultraviolet-activated persulfate system

In recent years, there have been many studies on treating pollutants with ultraviolet-activated persulfate (UV/PDS) system. In this paper, the biochemical treatment effluent of landfill leachate from garbage incineration power plant was treated. The effect of treating landfill leachate with UV/PDS system in the low-pressure external device and medium-pressure built-in device was compared; it was concluded that in the latter device, the photon quantity increased, the energy loss decreased, and the probability of generating free radicals in the reaction between photons and S₂O₈^2- increased, which result the treatment efficiency of this system was higher. In addition, the leachate was treated by combining the activation method of spinel composite (CuO-MgAl₂O₄) with UV activation method, called CuO-MgAl₂O₄/UV/PDS. The experimental data showed that the processing effect of segmented dosing PDS process was higher than that of one-time addition process. Under the same conditions, the removal rates of CODcr were 83.10% and 19.76%, respectively. One of the reasons for this result may be that excessive PDS in CuO-MgAl₂O₄/PDS system of the latter process inhibited the treatment effect. This paper analyzes the efficiency of UV/PDS system, as well as CuO-MgAl₂O₄/UV/PDS combination process which were used to treat landfill leachate under different conditions; the results showed that the medium-pressure built-in device and segmented-dosing process could get better treatment effect.