Rules of Activated Sludge

1) RULE:

The yield should range from 0.4 to 0.7 for heterotrophs and from 0.05 to 0.29 for autotrophs.

FUZZY RULE:

The yield for heterotrophs should be larger than the yield for autotrophs.

2) RULE:

If the retention time is too long then the system may become more alkaline.

FUZZY RULE:

The rention time should not be too long.

3) RULE:

If the dissolved oxygen is too low then more retention time is needed.

FUZZY RULE:

The dissolved oxygen should not be too low.

4) RULE:

The unaerated fraction of the reactor volume should be less than 50%.

FUZZY RULE:

The unaerated fraction of the reactor volume should be low to medium.