This document discusses strategies for addressing bulking and foaming problems in wastewater treatment plants. It outlines various chemical additions that can be used, including polymers, alum, ferric chloride, and ferrous sulfate. Chlorination is described as the most widespread method, and can be designed into new plants or retrofitted into older ones. Application points are given as directly into the aeration basin or the return activated sludge stream. The document also covers techniques for dealing with excessive foaming such as lowering mixed liquor suspended solids concentrations, chlorinating sludge, using water sprays, and foaming agents. It emphasizes the importance of process monitoring and control to maintain effluent quality.

1. Bulking and Foaming Problems PART 2
*

2. *
*When all else fails for bulking control
or poor settling:
*Chemical addition – When is the right time?
*Excessive filamentous growth
*Viscous or non-filamentous bulking

3. *
*What chemicals can be used?
*Polymers – does not increase sludge mass
*Aluminum sulfate (alum)
*Ferric chloride
*Ferrous sulfate -
*Powdered activated carbon
*Talc
*Paper fibers/clay

4. *Chlorination – the most widespread use
*Designed into new plants
*Retrofitted into older plants
*Common application points:
*Directly into aeration basin
*RAS stream (preferred location)
*

5. *RAS Stream Chlorination
*Directly into aeration basin
*RAS stream (most common)
*

6. *Chlorination
*Designed into new plants
*Retrofitted into older plants
*Common application points:
*Directly into aeration basin
*RAS stream (most common)
*

7. *
*Excessive concentrations:
*Lowering MCRT by reducing MLSS
*Chlorinating MLSS and/or RAS MLSS
*Use of water Sprays
*Application of Foaming Agents
*Removal of the scum/Foam should be complete
as not to re-enter the treatment process.

8. *

9. *
*Foaming/Froth/Scum will contain grease.
*This makes for a very slippery environment.
*Care must be taken for control and removal of
this hazard.
*Numerous Operators have been seriously
injured while removing this hazard.

10. *

11. *
*Use of a Graduated Cylinder as well as a
standard Settle-O-Meter can aid the operator
with identification of both foam and bulking
conditions.
*Critical timing of the test to simulate actual
operations is critical for best results.

12. *

13. *
*Bulking will take place in the Secondary
Clarifier.
*Filamentous Bacteria is the cause.
*Be mindful of why this happens:
*Air or gas in the sludge causes the sludge to
float.

14. *

15. *
*With bulking, the RAS MLSS concentration will
be reduced.
*When this occurs, the concentration is lowered
so the rate must be increased.

16. *
*Manipulating the RAS:
*Reduce the MLSS in the Secondary Clarifier
*Reduce SS loading while maintaining RAS BULK
withdrawal rate,
The SVI is then increased.

17. *
*EVERY POTW (Publicly Owned Treatment
Works) is built in “Trains”.
*Multiple treatment tracks so that the facility
can stay in operation during periods of
maintenance.
*Any maintenance that takes a basin or tank out
of service will change the hydraulic loading on
the facility, this can disrupt effluent water
quality.

18. *
*Poor Effluent Water Quality.
*High or Low SVI results.
*Increased number in flagellates or amoeba.
*Decreased number of stalked ciliates.
*All these would inspire a change in process
control.

19. *
*This is why we look under the microscope.
*If you wait too long to make a change based
entirely on effluent water quality, ultimately
you will violate your DMR and Permit.
*It takes time through a process to see a change
take place. Remember your sludge age or
MCRT? Days………….

20. *
*Good Operational Effluent: 2 or 3 times per
week.
*Poor Operational Effluent: twice per day
(morning and afternoon).
*Following a Process Change: daily or twice per
day until stabilization.

21. *
*Homework:
*Read Chapter 4 “Control of Activated Sludge
Bulking and Other Settling Problems”