Aged raw landfill leachate:: Membrane fractionation, H2O2/UV treatment and molecular size distribution analysis

Treatment of an aged raw landfill leachate with H2O2/UV was performed to find an effective way to cope with large refractory organic compounds. A 2(3) factorial design experiment, using leachate pH, H2O2 dose and UV fluence as factors, and COD, BOD5 and color as measured responses, showed that UV fluence was significant factor for COD and color reduction and BOD5 improvement; H2O2 dose was important for both COD and color reduction; and leachate pH was only significant to COD reduction. Then, the aged raw leachate and the membrane fractionated leachate samples were oxidized with H2O2/UV, and COD, BOD5, color and molecular size distribution were monitored. The COD removal efficiency of H2O2/UV on the fractionated samples varied from 12% to 33% depending on the sample initial quality. H2O2/UV reduced color effectively for the particle-free samples. After H2O2/UV treatment, BOD5 increase of the particle-free samples seemed to be only dependent on UV fluence. Molecular size distribution analysis demonstrated that no new peaks were observed after treatment except the sample of 0.45 mu m to 10k Da. Particles larger than 0.45 mu m seemed to hinder the reduction of COD and large molecule peaks.