Evaluation of Organic Matter Stability During the Composting Process of Agroindustrial Wastes

Abstract

Composting of wastes from citrus industrial processing (pastazzo and sludge) was studied in order to evaluate the evolution of organic matter during the process and to individuate chemical and/or biochemical techniques able to set the stability of the final product.Composts from two open-air piles of different composition were sampled every month during the whole period of composting (5 months) and the organic matter of each sample was characterised by chemical and biochemical techniques. Humification rate (HR%) and humification index (HI) were determined. Extracted organic matter of the six samples collected for each compost was investigated by isoelectric-focusing technique (IEF). The biochemical analysis were based on the study of C-mineralisation after the addition of each collected sample to soil. Results obtained clearly demonstrated organic matter evolution during composting processes. Humification rates increased and humification indexes decreased over time, while extracted organic matter showed electrophoretic behaviour typical of stabilised organic compounds. Moreover, mineralisation patterns confirmed the increased level of organic matter stability during the composting process.

Square‐Planar Coordinated Polyanions of Palladium, Platinum, and Gold Stannaborate [SnB11H11]2− Coordination Chemistry

“…In order to prepare the mixtures between GMF and the organic biomasses, the following starting materials were considered: dried vine vinasse (DVV), an anaerobically digested solid residues (constituted by exhausted stems, skins and grape seeds), obtained after distillation of the ‘ grappa ’, the exclusive Italian ‘acquavite’ ‘ pastazzo ’ (PAS), a by‐product from orange juice production, mainly formed by peel, membranes and seeds, rich in sugars, fibers and other residual materials,13 amounting to 50% of the whole fruit mass a quality compost (COMP), produced by composting pastazzo in combination with pruning residues from citrus orchards, already utilised as a soil amendment 14–16 …”

Compost from Fresh Orange Waste: A Suitable Substrate for Nursery and Field Crops?

“…Bioconversion of fresh orange processing waste was accomplished at the Agricultural Experimental Station (University of Reggio Calabria, Italy) following the turned pile composting system (Intrigliolo et al 2001;Tittarelli et al 2002). Briefly, an amount of pastazzo (chemical properties shown in Table 1) with an initial moisture content of 85.8% (Figure 2) was left drying for two weeks on a cemented pit (20 x 5 m) until the water content decreased down to 65%.…”

An Integrated Chemical, Thermal, and Microbiological Approach to Compost Stability Evaluation

“…Humification parameters, based on the fractionation of the extractable humic‐like and nonhumic organic C, have been successfully used for evaluating the stability level of compost (Dell'Abate et al, 1998; Hsu and Lo, 1999; Tittarelli et al, 2002). However, the extraction and fractionation of OM could have drawbacks, such as the alteration of some organic constituent (Stevenson, 1994) and the presence of substances interfering with the determination of humic‐like substances (Adani et al, 1995).…”