The sewage treatment plant at Tarnow included since 2018 a unit for thermal hydrolysis and digestion of the sludge and processed municipal sewage as well as sediments supplied from the treatment plants located near Tarnow (450 and 290 Gg of dry solid sewage sludge in periods 2018 and I-V 2019, resp.). A redn. of sewage sludge mass by over 60% (and more than 45% of dry matter) was achieved when compared to sewage treatment without addnL thermal hydrolysis and digestion.