Characterization of water-extractable organic matter during the biostabilization of municipal solid waste

Relationships between stability, maturity, water-extractable organic matter of municipal sewage sludge composts and soil functionality

“…Even if stability and maturity were sometimes considered as terms with no real distinction, some differences should be made: stability is an index of compost evolution, expresses the biodegradability of its organic matter and is mainly evaluated by means of respirometric measurements, while maturity is an index of the compost capability of sustaining plant growth, is linked to the elimination of phytotoxic compounds and is evaluated by plant or seed bioassays (Adani et al 2006;Bernal et al 1998;Said-Pullicino et al 2007a). Various parameters for evaluating compost stability and maturity, such as anaerobic gas formation potential, volatile solids content or organic carbon (C) content in solids (Shao et al 2009) have been proposed. Among them, the concentration of dissolved organic matter (DOM) was reported by a high number of works (Bernal et al 1998;Iannotti et al 1994;SaidPullicino et al 2007a;Zmora-Nahum et al 2005).…”

“…Among them, the concentration of dissolved organic matter (DOM) was reported by a high number of works (Bernal et al 1998;Iannotti et al 1994;SaidPullicino et al 2007a;Zmora-Nahum et al 2005). Indeed, the biochemical transformations of organic matter take place in the water-soluble phase (Shao et al 2009) and the concentration of water-extractable organic matter (WEOM), which is the fraction of DOM gently extracted in water and conceptually consisting of the mobile and available portion of the total DOM pool (Corvasce et al 2006;Zsolnay 1996), consistently decreases during composting (Said-Pullicino et al 2007a). This suggests the suitability of this parameter for compost evaluation.…”

“…WEOM consists of a heterogeneous mixture of compounds with different molecular sizes and complexities, ranging from simple sugars and organic acids to complex proteins and humic colloids (Lu et al 2013;Traversa et al 2010). It contains the organic materials for the production of polysaccharides and proteins (Said-Pullicino et al 2007a) as well as alcohols, aromatic compounds (He et al 2011), carbohydrates and amino-sugars (Shao et al 2009), whose concentration depends on the evolution degree of compost.…”

“…For these reasons, WEOM was studied to evaluate compost or vermicompost evolution (Lu et al 2013;Said-Pullicino et al 2007a;Shao et al 2009), as well as changes of humification and aromaticity along soil profiles (Corvasce et al 2006). WEOM characterization could be carried out by means of UV absorbance, fluorescence spectroscopy in the emission and excitation/emission matrix modes, excitation and synchronous fluorescence and additional spectroscopic-derived indexes (Corvasce et al 2006;Zaccone et al 2009), as well as through acid-base titrations (Fernandez et al 2007).…”

“…WEOM characterization could be carried out by means of UV absorbance, fluorescence spectroscopy in the emission and excitation/emission matrix modes, excitation and synchronous fluorescence and additional spectroscopic-derived indexes (Corvasce et al 2006;Zaccone et al 2009), as well as through acid-base titrations (Fernandez et al 2007). Moreover, WEOM is correlated to respiration and other compost parameters (Chica et al 2003;Shao et al 2009), thus has been proposed as cut-off value for compost maturity (Bernal et al 1998;Hue and Liu 1995;Zmora-Nahum et al 2005). However, while compost properties and soil fertility were extensively investigated separately (Barrena et al 2014;Baldantoni et al 2010;Guerrero et al 2007;He et al 2011;Nolan et al 2011;Pavan Fernandes et al 2005;SanchezMonedero et al 1999;Sciubba et al 2014), only a few works (Bustamante et al 2010;Lannan et al 2013;SanchezMonedero et al 2008) focused their attention on the relationships between compost and soil quality.…”