Treatment of Landfill Leachate RO Concentrate by VMD

Abstract

Reverse osmosis (RO) concentrate has been one of the concerned environmental pollution since the RO membrane is widely applied. RO concentrate has a dramatic impact on the useful life of landfill, surrounding soil and ground water. Thus, the RO concentrate is also urgent to be solved. In this research, we firstly explored the characteristics of vacuum membrane distillation (VMD) by monitoring the membrane flux after controlling for three variables: inflow temperature, inflow flux and vacuum degree downstream and found out the optimum operating conditions. Then we further tracked the running instances of the system by testing the membrane flux and the effluent pH, conductivity, TOC and COD at two different temperature. As for the membrane fouling and wetting, a SEM/EDX analysis was conducted and an efficient solution was given. Finally, we found out that when the vacuum pressure is set at 0.08Mpa, inflow flux is set at 200L/h and at 75℃ or 80℃, we can get a relatively ideal membrane flux. The deterioration of effluent quality and membrane fouling happened in the VMD experiment at 80℃ faster than at 75℃ and "soaking with alkali, acid and tap water + drying" process is available to function recovery.