Effect of organic waste amendments on degradation of PAHs in soil using thermophillic composting

Abstract

The feasibility of using various types of organic wastes including pig manure, sewage sludge, and soybean refuse for remediation of soil spiked with phenanthrene, anthracene and pyrene (PAHs) was evaluated through batch‐scale composting reactors. The most active degradation of PAHs occurred between day 4 to 30 and maximum removal at the end of composting accounted for 90% of the initial concentrations of the three PAH compounds. Among the three PAHs, degradation of pyrene in the composting mass was relatively slow as indicated by a longer lag period than that of phenanthrene and anthracene. This corresponded well with the high molecular weight and log K _ow values of pyrene. The organic amendments were effective in enhancing the degradation of PAHs, and pig manure amendment exhibited a slightly higher removal efficiency than sewage sludge and soybean refuse. A decrease in total organic matter in all treatments indicated that the decomposition process occurred. Toxicity test with cress seed germination was evaluated and no phytotoxidty was noted after 21 days of composting. This preliminary study positively supports that pig manure is an effective organic additive for bioremediation of PAH‐contaminated soil using composting as a treatment technology.

Keywords:

• Anthracene
• composting
• degradation
• organic wastes
• phenanthrene
• pyrene