Submitted to: Journal of Environmental Polymer Degradation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 26, 1998
Publication Date: N/A
Interpretive Summary: Bagasse, the stalk residue from cane sugar production, can be chemically modified so that it can be used to remove dyes from textile wastewater. Ideally, the modified bagasse and adsorbed dye should be disposed of by composting or spreading on farm land to minimize disposal costs and return their nutritive (carbon and nitrogen) value to the soil. This work was performed to determine whether soil microbes are able to digest (biodegrade) modified bagasse. We found that the biodegradability of modified bagasse is much less than unmodified bagasse (which normally degrades slowly over a period of about a month under our test conditions). This means that the modified bagasse should not be composted or applied to land. It is preferable, therefore, to reuse (recycle) the modified bagasse when possible and then incinerate the spent material.
Technical Abstract: Quaternized, crosslinked sugarcane bagasse can adsorb anionic dyes from textile wastewater. Disposal of dye-saturated adsorbent by composting or land application would require that modifications made to the bagasse do not interfere with its decomposition. The impact of quaternization and crosslinking on bagasse biodegradability was examined. Bagasse in varying states of modification was mixed with soil and monitored for carbon dioxide evolution for 4 weeks at 27 deg C. After subtracting the amount of carbon evolved from control soil samples, the net carbon evolved from the bagasse samples was determined and used as a measure of their extent of biodegradation. Biodegradability decreased in the order: bagasse (approx. 60% degraded after 4 weeks) > quaternized bagasse > quaternized, epichlorohydrin-crosslinked bagasse > quaternized, methylene-bis-acrylamide-crosslinked bagasse > epichlorohydrin-crosslinked bagasse (less than 5% degraded). Crosslinking severely impacted biodegradation, probably by preventing the penetration of (hemi)cellulytic and lignolytic enzymes into the interior of the modified bagasse particles. It is concluded that the biodegradability of quaternized, crosslinked bagasse is too low for composting or land application.