Aerobic granular sludge in an SBR-system treating wastewater rich in particulate matter

摘要

Aerobic granular sludge was successfully cultivated in a lab-scale SBR-system treating malting wastewater with a high content of particulate organic matter (0.9 gTSS/L). At an organic loading rate (COD_(total)) of 3.4 kg/(m~3·d) an average removal efficiency of 50% in COD_(total) and 80% in COD_(dissolved) was achieved. Fractionation of the COD by means of particle size showed that particles with a diameter less than 25-50 μm could be removed at 80% efficiency, whereas particles bigger than 50 μm were only removed at 40% efficiency. Tracer experiments revealed a dense sessile protozoa population covering the granules. The protozoa appeared to be responsible for primary particle uptake from the wastewater.