RETRACTED: Overview of modern methods of treatment and disposal of sewage sludgeKamshat Jumasheva, Samal Syrlybekkyzy, Akmaral Serikbayeva, Botakoz Suleimenova and Zhansaule AltybayevaE3S Web Conf., 420 (2023) 07008DOI: https://doi.org/10.1051/e3sconf/202342007008