ANAEROBIC-DIGESTION OF WASTES CONTAINING PYROLIGNITIC ACIDS

Small quantities of residues from wood pyrolysis (pyrolignitic acids) added to swine slurry were digested in two laboratory anaerobic, fixed-bed, upflow digesters, filled with wood-chips or PVC as support media. The two digesters showed about the same efficiency when treating swine slurry containing pyrolignitic acids up to 6·5% (v/v). With a 10% (v/v) concentration, COD removal efficiency, specific biogas production, pH of the effluent, utilized as process-efficiency parameters, decreased remarkably for both plants. However, the digester with wood-chips showed a stronger resistance to the presence of pyrolignitic acids. © 1990.