Ozone Pre-Treatment to Enhance Anaerobic Degradation of Refractory Landfill Leachate Organics

• Other Authors: Qiao, Yu (authoraut)
• Format: Others
• Language: English; English
• Published: Florida State University
• Subjects: Civil engineering; Environmental engineering
• Online Access: http://purl.flvc.org/fsu/fd/FSU_migr_etd-5421

Advanced oxidation processes (AOPs) have garnered recent consideration as an option to reduce organic loading, and the recalcitrance of mature landfill leachate. Hydroxyl radicals (*OH) are produced during AOPs, which are effective in destroying organic chemicals. To investigate the potential for leachate conditioning by pre-ozonation treatment (O3/H2O2 and O3), low-mg/L level ozone stock solutions were spiked into an `old' landfill leachate (0 to 7.5mg/L O3). The stoichiometric ratio of 1.1:1 was determined to be the optimal molar ratio of O3 to H2O2 based on the biodegradability of the leachate organics. The leachate conditioning includes: measurement of the three anthropogenic contaminants tris-(2-chloroethyl) phosphate (TCEP), tris-(butoxyethyl)-phosphate (TBEP) and 17ß-estradiol (E2) by pre-ozonation treatment and the pre-ozonation followed by anaerobic treatment; COD and BOD5/COD analysis of the ozonated leachate; measurement of the methane and total gas formation during the anaerobic incubation; also the COD analysis of the mixed leachate and sludge solution during the anaerobic incubation. When treating with O3 and O3/H2O2 pre-oxidation, the removal of E2 was 65% at the ozone dose of 4.5mg/L to 5.4mg/L, which was higher than that of TCEP and TBEP. Based on one-way ANOVA analysis, the O3/H2O2 pre-treatment was observed to have significantly improved degradation of E2 during anaerobic incubation of oxidized leachates (removal rate of E2 was 53.7% after 15 days of incubation). However, O3 pre-treatment improved post-ozone degradation of TCEP and TBEP by 26% and 39.3% as compared with O3/H2O2 after 15 days of incubation. In addition, overall anaerobic activity was not impacted by the applied ozone pre-treatments, as measured by methane formation, total gas formation, and COD removal. In general, low-mg/L ozone pre-treatment, prior to anaerobic incubation, was found to improve biological degradation === A Thesis submitted to the Department of Civil and Environmental Engineering in partial fulfillment of the requirements for the degree of Master of Science. === Fall Semester, 2012. === September 28, 2012. === Advanced oxidation processes(AOPs), anaerobic, leachate, ozone === Includes bibliographical references. === Michael Watts, Professor Directing Thesis; Gang Chen, Committee Member; Amy Chan Hilton, Committee Member.