Division Aerobic test system

The aerobic test system described in this test method consists of an aerobic water layer (typical oxygen concentrations range from 7 to 10 mgl^-1 ) and a sediment layer, aerobic at the surface and anaerobic below the surface (typical average redox potentials (E_h) in the anaerobic zone of the sediment range from -80 to -190 mV). Moistened air is passed over the surface of the water in each incubation unit to maintain sufficient oxigen in the head space.