The ODM-100 from Challenge Technology allows the user to place the device at any point in the treatment process to monitor biological activity via respiration in a continuous or sequential batch mode, depending on what information the user needs. It allows for the continuous monitoring of the influent loading used to adjust processes and warn of potential upsets or toxic events. This application also allows evaluation of loading history for daily and seasonal optimization of processes. It can be used to optimize aeration and return activated sludge volumes based on real-time loading, or continuous monitoring of mixed liquor for rapid assessment of changing oxygen demand in an aeration basin that is not dependent on a plant aeration system. It can be used for batch monitoring of mixed liquor and detailed evaluation of treatment processes at any point in-plant, or batch testing of trucked-in or industrial wastewater to evaluate treatability and possible toxic events. 479/927-1008; www.challenge-sys.com.