Search

The disposal of municipal biowaste is associated with the formation of malodorous and frequently hazardous volatile compounds. The composition of volatile pollutants formed during composting of mechanically sorted organic fraction of municipal solid waste (ms-OFMSW), sewage sludge (SS), food waste (FW), and wood waste (WC) during 28 days in a laboratory setup was analysed using electrochemical measurements, gas chromatography, and solid phase microextraction. Despite the close biodegradation intensity of SS+WC, ms-OFMSW, and FW+WC, the average temperature values were 57.0, 51.7, and 50.6 °C. The emission of volatile substances per day were: CO2 0.64, 0.68, and 0.64 g/kg, NH3 22.3, 93.1, and 4.9 µg/kg, CH4 5.3, 1.5 and 8.7 mg/kg, H2S 5.0, 3.3 and 1.8 µg/kg organic matter. The ratios of emission from SS+FW, ms-OFMSW and FW+WC for inorganic substances were 1.0, 1.1, and 1.0, and for organic compounds (VOC) were 1, 24, and 123. A total of 121 VOC was identified. The 12 N-containing compounds detected at the beginning of composting, some of which are highly toxic, ranged from 3.2 to 21.0% of the total VOC and belonged to amines with a very low olfactory thresholds and heterocyclic compounds. The results of this research help to optimise the systems used to remove pollutants from exhaust air.

The degradation of polylactide (PLA) films of different structures under conditions of controlled composting has been studied. We have demonstrated that PLA underwent degradation within one month in a substrate that simulated standard industrial composting. Regardless of the initial structure of the samples, the number-average molecular weight (Mn) decreased to 4 kDa while the degree of crystallinity increased to about 70% after 21 days of composting. Addition of an inoculant to the standard substrate resulted in the accelerated degradation of the PLA samples for one week due to an abiotic hydrolysis. These findings have confirmed that industrial composting could solve the problem of plastic disposal at least for PLA.