In addition to the comments ...
Published by Nick Walmsley, Water New Zealand - Technical Co-ordinator
In addition to the comments below about organic loading, flushing rates and consequential hydraulic capacity of the system, including drains, there will need to be a review of the air movement. With less porosity more slime will grow and it will be easier to block the pores. Equally there will be more oxygen required from the air supply so make sure that the current fan system can handle both changes in pressure and perhaps increased recirculation rates. There will also be more solids transport from flushing and slightly greater solids loading on the downstream clarifier.