Bioremediation of Diesel Contaminated Soil Using Spent Mushroom Compost
Open Access
- Author:
- Eramo, Alessia Giuseppina
- Graduate Program:
- Environmental Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- May 12, 2009
- Committee Members:
- Rachel Alice Brennan, Thesis Advisor/Co-Advisor
Rachel Alice Brennan, Thesis Advisor/Co-Advisor - Keywords:
- composting
bioremediation
spent mushroom compost
diesel fuel
soil contamination - Abstract:
- Composting has been shown to be an effective bioremediation technique for the treatment of hydrocarbon-contaminated soil. In this research, spent mushroom compost (SMC), a sustainable, inexpensive, and abundant byproduct of the mushroom industry, was analyzed for its ability to support the remediation of soil contaminated by a diesel fuel spill. Chitin, a nitrogen-rich polymer derived from crab shell material, was also investigated as a nutrient amendment to counteract the nitrogen loss commonly observed in petroleum-contaminated soils. The approach was tested on contaminated soil and SMC obtained from the California Mushroom Farm, Inc. The results of this study will be used to guide the implementation of aerobic composting for remediation of diesel-contaminated soil at the site. Sacrificial batch microcosm tests were used to evaluate the effect of substrate/nutrient addition and elevated temperatures on the rate of diesel total petroleum hydrocarbon (TPH) remediation in a series of two experimental phases. In Phase I, the conditions evaluated were soil + SMC, soil + SMC with crab-shell chitin, and soil only (control). In Phase II, TPH removal was monitored at three temperatures typically encountered during composting: 22 oC, 30 oC, and 50 oC. In Phase I, all substrate-amended microcosms were successful at diesel removal. Microcosms amended with SMC and chitin showed an advantage at various points throughout treatment but did not enhance overall TPH remediation when compared to microcosms amended with SMC only. In Phase II, microcosms showed different TPH removal trends at early times depending on temperature, but overall, it was determined that none of the various temperature conditions provided an advantage for remediation. After 160 days, TPH concentrations in microcosms were reduced from approximately 1600 to 210 ppm at 22 oC, 180 ppm at 30 oC, and 270 at 50 oC for removals of 87%, 89%, and 83%, respectively. Denaturing Gradient Gel Electrophoresis (DGGE) was conducted using universal bacterial 16S rRNA gene primers to characterize the microbial community at different points during treatment. A diverse community was shown to be present in all conditions and time points analyzed. Preferential enrichment of specific community members or hydrocarbon degraders was not found. Functional overlap by various species breaking down the organic material in the system may be responsible for hydrocarbon degradation as well. Composting treatment of diesel contaminated soil using SMC from The California Mushroom Farm was compared to similar treatments using other locally available low cost waste substrates. SMC from The Pennsylvania State University Mushroom Testing Demonstration Facility and sewage sludge-based compost from The University Area Joint Authority (UAJA) Wastewater Treatment Plant promoted the highest TPH removal, CO2 production, and O2 usage as compared to The California Mushroom Farm SMC. The highest TPH removal (43%) was observed in microcosms containing Penn State SMC. This enhanced performance is probably linked to the higher carbon and nitrogen contents available in UAJA compost and Penn State SMC per dry mass as compared to The California Mushroom Farm SMC. The results of this study demonstrate that SMC can serve as an effective compost amendment to treat weathered, diesel-contaminated soil. Additionally, several other readily available waste substrates can be utilized in this type of low cost, low energy remediation system. Optimal conditions for microbial growth and activity, particularly sufficient O2 and moisture, should be provided at the onset of treatment and monitored actively throughout the course of remediation to ensure maximum hydrocarbon degradation.