Before the reason for poor ...

Before the reason for poor sludge settleability can be pinpointed, a diluted settleometer test must be run. A simple old-sludge condition, with just too much sludge in the system, will show greatly improved settling in the diluted test. However, a bulking situation, even though it shows some improved settling, will not show large improvement.The required pressure is a decrease in the total system sludge mass. Increased wasting is required to accomplish that objective. This problem is very common. If it is reduced, the concentration gets so low that effective settling is impossible.Normally, one would try to reduce the MCRT, but this requires wasting and a reduced MLSS and it seldom works in this case. It may be worth trying to grow some filaments, such as low DO filaments, that would slow the settling and improve the capture of solids. Maintaining a DO between 0.1 and 0.5 in the aeration tank will usually allow low DO filaments to grow. Be careful