A method of treatment of sewage comprising adding at least one cell signalling chemical (CSC) to a sewage substrate, wherein the at least one CSC regulates activity of a microbial population in the sewage substrate. In particular, methods of reducing odor in sewage treatment systems, preventing corrosion in sewage treatment systems, enhancing microbial digestion of sewage, managing methane gas production in a sewage treatment system, enhancing digestion of sewage sludge, resuscitating dormant microbes or microbes that are in a starvation or stationary phase in a sewage substrate and controlling the bacteria responsible for oxidation or reduction of nitrogenous compounds in a sewage substrate, are provided.