Particle size analyses in relation to the operation of the activated sludge process

Abstract The nature of the particle size distributions of activated sludge particles would appear to influence both the settlement and thickenability of the sludge. However, there are few methods available that can quickly and reliably provide particle size analyses of sludge samples. This assessment of an optical/electronic method showed that it was quick and provided reproducible and repeatable data. The results produced during this investigation showed how the particle sizes of activated sludge varied with the operational conditions prevailing in the aeration tank.