Home – Home – Jornals – Chemistry for Sustainable Development 2023 number 1

Results of the studies of municipal sewage sludge (MSS) oxidation during pumping a water-oxygen fluid through its bed under uniform (1.5 K/min) temperature ( T ) rise up to 733 K are presented. The temperature dependences of the yield of volatile and liquid products, as well as data on the content of mineral components in the ash residue and water collected at the reactor outlet are obtained. It follows from the temporal dependences of the reactor wall temperature, the power of the ohmic heaters, and the degree of carbon burn-up that the major part of MSS organic matter is oxidized at T < 602 K. According to the data of IR spectroscopy and ultimate analysis, an increase in the oxidation duration and temperature leads to a decrease in the content of hydroxyl and amide groups and an increase in the proportion of aromatic compounds in liquid products. The volatile products obtained at T > 673 K contain only inorganic substances - CO₂, CO, N₂, and NH₃. It is revealed that the major part of nitrogen in the form of NH₄⁺ ions passes into the aqueous phase, while the elements Si, Ca, Al, Fe, P, S, K, Na, and Mg are concentrated in the ash residue.