Use of Sugarcane Bagasse as Carbon Substrate in Permeable Reactive Barriers: Laboratory Batch Tests and Mathematical Modeling
R.C. Mattos, P.S. Hemsi, E.Y. Kawachi, F.T. Silva
Soils and Rocks, São Paulo, 38(3): 219-229, September-December, 2015 | PDF
The combination of the lignocellulosic residue sugarcane bagasse and poultry litter as carbon and nutrients sources, respectively, in organic permeable reactive barriers for remediation of metal laden acid mine drainage has not yet been extensively tested and may be promising based on chemical composition. This system is being tested in the laboratory by means of microcosm batch experiments using sugarcane bagasse with and without poultry-litter as nitrogen and phosphorous source. As expected based on the compositions of sugarcane bagasse and poultry litter, the experiments (duplicate) combining both residues achieved the highest rates of sulfate reduction, between ~ 30 to 45 mg sulfate/L-day, and better sustained these rates throughout the duration of the experiment (78 days). Also, pH values increased from~6to8, and the oxidation-reduction potential achieved < -100 mV, indicating anaerobic sulfate-reducing conditions. Mathematical modeling performed on these experiments, with a previously-tested model, resulted in simulated results that approached the experimental data when the sugarcane bagasse was modeled as comprising a cellulose fraction with a Contois specific degradation rate similar to that for wood chips and leaf mulch, plus an additional easily-degradable fraction to account for the occurrence of soluble sugars in sugarcane bagasse.
Submitted on June 25, 2015; Final Acceptance on November 4, 2015; Discussion open until April 30, 2016.