Biological treatment of condensate from aerobic digestion of biodegradable waste: A German example
Separation of household waste into recyclable, biodegradable, and nonbiodegradable components is required in Germany. Aerobic digestion of the biodegradable component can further minimize the waste volume. During aerobic digestion a hot humid exhaust stream, containing volatile organic and other low molecular weight compounds, is produced. Cooling this stream produces up to 350 L of condensate per ton of biodegradable feed material. Efficient treatment of this condensate is essential for a practical aerobic digestion process. Reuse of the condensate could lead to improved process economics. In this paper, condensate treatment by biological degradation using intermittent sparging has been investigated. An inorganic ultrafiltration membrane was used to separate the biomass from the treated water. It is shown that this one-step intermittent nitrification/denitrification process may be used to reduce COD, total nitrogen, and ammonia nitrogen concentrations to acceptable values for direct discharge of the treated water into rivers. © 2004 American Institute of Chemical Engineers Environ Prog, 23: 215–221, 2004