Characterization of waste organic matter by FT-IR spectroscopy: Application in waste science

A series of experiments has shown that FT-IR (Fourier transform infrared) spectroscopy is a helpful tool for characterizing waste organic matter, its decomposition, and stabilization in rotting processes. A specific set of differently treated input materials, originating from various composting plants, was chosen to reflect a wide range of spectroscopic properties. The approach to FT-IR spectra interpretation is presented. Changes of relative absorbances of the band at 2925 cm(-1) (methylene groups of aliphatics) reflect the progress and dynamics of composting processes. Different processes can be compared by the specific development of their 2925 cm(-1) band. Nitrate was quantified by calibrating nitrate band heights with added amounts of KNO3. The concentrations and band heights (absorbances) were linearly correlated (R-2 = 0.9968, SD = 0.001). Bands of inorganic components are useful to assess the decomposition process because they also indicate the development of organic matter. Different wastes can be distinguished by their fingerprint region (1500-900 cm(-1)). This region also reveals fresh and undecomposed materials. The presence or absence of specific bands provides information about the decomposition status of materials.