METAL BINDING BY HUMIC SUBSTANCES AND DISSOLVED ORGANIC MATTER DERIVED FROM COMPOST

Abstract

Composting of MSW is of great importance for both developed and developing countries. It can be applied with the aim of reducing the total volume of MSW, thus lowering landfilling costs, and if properly treated after careful source separation it can be a source material for substrate used in greenhouses or to amend soils with OM. It is well known that compost maturity is of great importance from the point of view of the compost quality, as well as for cost optimization of the composting facility. Due to its importance and complexity, the search for ideal parameters of composting maturity is ongoing. Advanced chemical, physical and spectroscopic methods of compost maturity have been reviewed in this work. The bulk compost material has been the focus of earlier studies, yet HS and even more so the DOM and its fractions have become the focus of concern in more recent studies, as well as in the present one. It seems that DOM fractions are the most labile ones within the decomposing OM and therefore, the point at which changes in their content and composition occur seems to be a good indicator of maturity. Examination in detail of the DOM and its fractions with advanced chromatographic, spectroscopic and chemical techniques, along with the evaluation of metal binding to these fractions, was the aim of this review. It has been confirmed that decreased DOC and hydrolyzable carbohydrates are characteristic of the OM decomposition process taking place during composting. Hydrolyzable amino acid concentrations fluctuate, and therefore, cannot serve as indicators of maturity. Key