Chemical characterization of ash generated from alfalfa stem gasification: Agricultural and environmental implications. Quarterly report, July 1, 1997--September 30, 1997

Abstract

This progress report provides results of Toxicity Characteristics Leaching Procedures (TCLP) and Synthetic Leachate Test Procedure (SLTP) for the alfalfa stem ash. The TCLP simulates solute leaching in landfill by using acetic acid as a solvent and SLTP simulates potential for leaching from synthetic acid rain. This report also provides information on detailed chemical characterization of organic and inorganic constituents of the ash. The analysis performed includes information on compounds that may represent a potential risk to human or animal health and those constituents that may have beneficial use as soil amendments and conditioners. A sample of the fly (filter) ash from the test burn conducted in Finland was received in May 1997 and used for initial investigation. Three additional fly ash samples and one sample of bottom ash (reactor bed ash) were received in June 1997. The samples were either tested at the University of Minnesota or sent to a reputable laboratory, and various tests were conducted according to the standard methods. The result of the comprehensive tests conducted in May 1997 (report submitted previously) were used as a screening procedure for conducting tests on June 1997 samples. To provide a more comprehensive representation of ash characteristics the results for fly ash received in May are presented along with results from fly ash samples received in July. The average, range and coefficient of variation (CV) are provided. The TCLP and SLTP tests conducted in the laboratory indicated that the concentration of heavy metals were below or close to the detection limits for fly and bottom ash samples (Tables 1 and 2). The ash was also characterized for a number of classes of organic compounds that may pose potential environmental or health risks. These are polyaromatic hydrocarbons (PAHs), total and individual dioxin and furan compounds.