During the first and second weeks of October 2023, International Ecological Engineering Society Conference 2023 and the 19th International Symposium on Waste Management and Sustainable Landfilling took place in Chania (Greece) and Sardinia (Italy), in which Cecilia Polizzi from Università degli Studi di Firenze and Francesco Pasciucco from Università di Pisa presented their research work devoted to modelling and Life Cycle Assessment of two novel biological treatment trains proposed for resource recovery from tannery WWTPs and pigment production industry’s flue gases by the RECYCLES project in WP3 and WP4.