De Bavay was born in Vilvoorde, Belgium, second son of R. de Bavay, Knight of the Order of Leopold / a son of Xavier de Bavay and his wife Marie Thérèse de Bavay née de Bontridder. He was educated at a college in Namur, and graduated in 1873 qualified as a surveyor. He undertook further studies at Gembloux, and found employment as a brewer and chemist. In the late 1870s he left for Ceylon, where he worked as a plantation manager. In March 1884 De Bavay arrived in Melbourne and worked as a brewer at Thomas Aitken's Victoria Parade Brewery. Following E. C. Hansen's discovery of the impact of yeast variety on the beer quality, De Bavay grew Australia's first pure yeast expressly cultured for top-fermentation brewing. His students included Jack Breheny. In 1894 De Bavay joined the Foster's Group following a recommendation by Montague Cohen, a director of the company, and made improvements to their lager production. He then joined Cohen in wine production, establishing a vineyard at Woori Yallock in partnership with Cohen. He also acted as a consultant to Perth's Swan Brewery and Hobart's Cascade Brewery and, later, Carlton & United Breweries, in all of which Cohen and Baillieu had an interest. In 1889 he proved that Melbourne's water supply was potentially being contaminated by sewage via fireplugs. This led to a State Royal Commission, resulting in removal of the devices and an immediate improvement in quality of the water supply. De Bavay was attracted to the "sulphide problem" of Broken Hill, where great mounds of potentially valuable zinc blende had accumulated, but could not be shipped economically because of the gangue content. If an economical method of separating the ore were developed, a great new industry would be created. C. V. Potter and Guillaume Delprat had made useful work on development of froth flotation and by July 1904 he had evolved his own process, skin or film flotation. In 1904 he founded de Bavay's Sulphide Process Co. Ltd, with Cohen and William Baillieu, and the following year another company De Bavay's Sulphide Process Co. Ltd to purchase De Bavay's patents. In 1909 Amalgamated Zinc Ltd was founded to put the process into practice. After Australia entered the Great War in 1914, De Bavay was approached by the Minister for Defence, George Pearce, to develop a process for production of acetone, needed for manufacture of cordite. Within two weeks he had developed a process based on the fermentation and distillation of molasses. He made a gift of the patent to the Commonwealth of Australia. De Bavay was put in charge of development and erection of the Government's Commonwealth Acetate of Lime Factory. De Bavay was naturalized in November 1902. He died at his home on Studley Park Road, Kew, Victoria aged 88. His remains were buried in Melbourne General Cemetery.
Captain Charles de Bavay married Vera Tolley on 20 August 1919. He was brewer with Carlton Brewery, she was member of Tolley family, winemakers of South Australia
Vera de Bavay married John Higgs on ?? 1833, lived in Surrey, England
Xavier de Bavay married Dulcie Lucille Cooper on 19 June 1922. He was manager of the Cascade Brewerv Co. Ltd, Hobart
