The ocean environment is being used increasingly for the disposal of municipal sewage. Saltwater sewage systems are also in use in several locations. This research describes the microbially mediated degradation of the particulate fraction of sewage in saltwater media. Since the soluble fraction of sewage shows equal oxygen uptake, compounds thought to be representative of the particulate fraction of sewage were tested and found to be degradable in both freshwater and saltwater. Cellulose, however, did not seem to undergo reaction in saltwater within twenty days using organisms resident in domestic waste. Organisms from the marine environment were obtained and used to show that cellulose degradation was possible in saltwater media. Confirmatory data based on biomass and substrate depletion are accomplished using techniques developed for use in systems in which solid substrates are involved.