Biostabilization of mechanically separated municipal solid waste fraction

Abstract

Municipal solid waste was processed by a mechanical–biological end composting process both in pilot and full‐scale plants. The organic fraction obtained by mechanical treatment (fraction → < 50 mm) was processed at a high composting rate for 37 days followed by a curing phase of 79 days. Process parameters were registered and kept in an optimal range (oxygen > 140 ml l−1, temperature < 65°C, moisture > 500 g kg−1 w.w.). After the high‐rate phase, the products obtained showed a high degradation coefficient and good biological stability (ΔVS = − 54.75% and − 35.35%, DRI = 300 and 500 mg O2 kg−1 VS h−1, respectively, for pilot and full‐scale plants) especially for the pilot plant, indicating that it is not possible to obtain the same performance for a full‐scale plant as obtained under laboratory conditions. Nevertheless, the successive curing phase showed less of a discrepancy between the two processes (ΔVS = − 66.33% and − 56.87%, DRI = 280 and 360 mg O2 kg−1 VS h−1, respectively, for pilot and full scale plants). The quality of the stabilized product was tested by biogas production tests. As expected, a sample processed in the pilot plant produced less biogas (26 l kg TS−1) than that obtained at full scale (40 l kg TS−1). An unprocessed sample produced less biogas owing to the production of organic acids, which, by lowering the pH, inhibit the generation of gas.

Composting of cow manure and rice straw with cow urine and its influence on compost quality

“…Generally, the MC decreased over process time in both compost piles, but decreased greater in pile A. The decrease of MC during composting course was in agreement with comparable data from other authors (Marco et al, 2010;Adani et al, 2000;Tao et al, 2011). Turning operations which were performed along the process should tend to decrease moisture contents.…”

Monitoring the biological activity of the composting process: Oxygen uptake rate (OUR), respirometric index (RI), and respiratory quotient (RQ)

“…The respirometric index has been proposed both as a biological activity indicator and a stability index (Ianotti et al, 1993;Adani et al, 2000). Among the different strategies used for the determination of the respirometric index, one of the most popular, simple, and low-cost techniques is the static respirometric index (SRI, or simply RI), which is carried out off-line by incubating a compost sample and calculating the oxygen consumption.…”

Dynamic Respiration Index as a Descriptor of the Biological Stability of Organic Wastes

“…Table 1 shows that this study was based on 16 different organic waste types of differing origins and compositions representative of products from Italian solid urban waste treatment systems (biostabilization, biodrying, and composting). Samples 1 to 6 were biostabilized wastes obtained by mechanical biological treatment of municipal solid waste (MSW) (primary screen at 50 mm and successive high‐rate composting of the undersize fraction, i.e., the organic fraction) (Adani et al, 2000). In particular, Samples 1 to 3 were sampled at time zero.…”

“…B iological processes such as composting, biostabilization, and biodrying are used in solid waste management to convert waste matter into agriculturally useful products (Chen and Inbar, 1993), safe refuse for disposal in landfills (Wiemer and Kern, 1996; Adani et al, 2000), and refuse‐derived fuel (Calcaterra et al, 2000). Irrespective of the process, all these methods achieve high levels of biological stability by proceeding from an aerobic process to one of degrading organic matter.…”