The thermal treatment of waste is a source of energy recovery and thus an important element of mature waste systems. For the past two years, we have been expanding Warsaw’s ZUSOK, which has been producing green heat and electricity for Warsaw from mixed waste since the beginning of the millennium, and after expansion will be the largest thermal waste conversion plant in Poland. The investment is attracting a lot of professional interest. On 23 November 2023, we hosted participants at the annual sector conference ‘Thermal Waste Conversion. Energy recovery’. The host – Abrys Sp. z o.o. – introduced a study visit to ZUSOK into this year’s programme. More than 120 conference participants saw the plant undergoing expansion and modernisation up close, and also had the opportunity to talk to the investor (MPO Warsaw) and the main contractor (POSCO E&C) about the implementation of a major investment carried out on an active facility.