DISSOLVED OXYGEN IN GRAVITY SEWERS - MEASUREMENT AND SIMULATION

Dissolved oxygen (DO) concentrations were continuously measured during 2 month in a 3.6 km intercepting sewer. DO showed significant diurnal variations mainly caused by changes in the organic matter composition of the wastewater. At low temperatures the gravity sewer was strickly aerobic. Towards the end of the campaign, DO concentration decreased as temperature increased and the sewer became anaerobic part of the day. A conceptual model that takes into account bulk water and biofilm DO uptake as well as reaeration was used to simulate the DO measured.