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 14C-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 14CH4 and 14CO2, was 55.5, 25.7, 52.0, and 2.5% for purified cellulose, LC, x-C, and AGM, respectively. Total recovery of radiolabel, after measure ment 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.
A test cell of 3-m by 6-m located at the mid-point of a gasoline spill site was selected to test the hypothesis that the rate of hydrocarbon biodegradation is influenced by the spatial distribution of the electron acceptors, aqueous geochemistry, and microbial population. Multilevel samplers (MLSs) were installed at four corners of the test cell for groundwater sampling. Sampling ports were placed at 0.3-m intervals from 1.5 to 4.8 m below land surface (bls). A 0.91-m by 12.7-cm sediment core (from 3.3 to 4.2 m bls) in the center of the MLSs was collected. The core was cut into 7 sections, and each was used for sediment extractions, microbial enumeration, grain size distribution, and microcosm studies. Groundwater analytical results indicate that iron reduction was the dominant biodegradation process within this test cell. Iron-reducing process caused the preferential removal of certain compounds. Microbial enumeration results show that the distribution of microbial population varied with depth and sediment materials. Lower microbial population was observed in those sections with higher portion of clayey materials. The less permeable materials would limit the bacterial transport, decrease the bioavailability of Fe(III) to iron-reducing bacteria, and thus cause the low biodegradation activity. Results suggest that using blended sediments for biodegradation rate measurements may provide misleading results.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.