Testing anaerobic biodegradability of polymers in a laboratory scale simulated landfill

The objective of this research was to develop an improved technique for measurement of anaerobic biodegradability that more closely simulates decomposition in landfills. Tests were conducted in 2-L reactors that contained a mixture of C-14-labeled test material, fresh refuse, and decomposed refuse as a seed. The four materials evaluated included a pure cellulose, a lignified cellulose (LC), a citric acid cross-linked cellulose (x-C), and a polyacrylate absorbent gel material (AGM). Material biodegradability, as measured by production of (CH4)-C-14 and (CO2)-C-14, was 55.5, 25.7, 52.0, and 2.5% for purified cellulose, LC, x-C, and AGM, respectively. Total recovery of radiolabel, after measurement of residual label in the leachate and decomposed refuse, was 77.4, 95.2, 74.1, and 66.7%, respectively. The reactor system provided repeatable results and simulated the refuse decomposition cycle in 6 months. Tests demonstrated that the biodegradability of x-C, a newly developed material, was comparable to that of pure cellulose and greater than that of LC. Cellulose in both forms is typically buried in landfills.