Investigation of bioreactors by instrumented flow-following sensor particles

Instrumented flow-following sensor particles have been developed for investigation of hydrodynamic and biochemical processes chemical reactors and bioreactors, where standard measurement techniques are not applicable. The sensor particles allow autonomous long-term measurement of spatially distributed process parameters in the chemically and mechanically harsh environments of agitated industrial vessels. Each sensor particle comprises of an on-board measurement electronics that logs the signals of the embedded sensors. A buoyancy control unit enables automated taring to achieve neutral buoyancy of the sensor particles. Moreover, controlled floating of the sensor particles is possible to expose them for recovery from the fluid surface. The paper presents exemplary results from tests in an air-water column reactor, a pilot biogas digester and a waste water treatment plant.