Co-composting of paper mill sludge and hardwood sawdust under two types of in-vessel processes.
Recycling of organic residues by composting is becoming an acceptable practice in our society. Co-composting dewatered paper mill sludge (PMS) and hardwood sawdust, two readily available materials in Canada, was investigated using uncontrolled and controlled in-vessel processes. The composted materials were characterized for total C and N, water-soluble, acid-hydrolyzable, and non-hydrolyzable N, extractable lipids, and by Fourier Transform Infrared (FT-IR) spectrophotometry. In the controlled scale process, the loss of organic matter was approximately 65% higher than in the uncontrolled process. After undergoing initial fluctuations in N fractions during the first two days of composting, by the end of the process, concentrations of water-soluble N decreased while those of acid-hydrolyzable and nonhydrolyzable N increased in the controlled process, whereas in the uncontrolled process, water-soluble N increased, but N in the other two fractions decreased continuously, indicating that the biochemical transformations of organic matter were not completed. Data on extractable lipids and FT-IR spectra suggest that the compost produced from the controlled process was bio-stable after 14 days, while the uncontrolled process was not stabilized after 18 days. In addition, FT-IR data suggest the biological activity during composting centered mainly on the degradation of aliphatic structures while aromatic structures were preserved. The co-composting of the PMS and hardwood sawdust can be successfully achieved if aeration, moisture, and bio available C/N ratios are optimized to reduce losses of N.
Dinel
Henri
H
Eastern Cereals and Oilseed Research Centre, Agriculture and Agri-Food Canada, Ottawa, Ontario, Canada. denise.drd@sympatico.ca
Marche
Todd
T
Schnitzer
Morris
M
Paré
Théophile
T
Champagne
Pascale
P
D001673:Biodegradation, Environmental; D002244:Carbon / Q000032:analysis* / Q000737:chemistry; D007700:Kinetics; D008055:Lipids; D009584:Nitrogen / Q000032:analysis* / Q000737:chemistry; D012037:Refuse Disposal / Q000379:methods*; D012995:Solubility; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D014934:Wood
D008055:Lipids; D002244:Carbon; D009584:Nitrogen