NITRIFICATION AND ACTIVATED SLUDGE FOAMING ...

This chart presents an example of targeted consistent ammonia load by variable control of flow rates
relative to varying ammonia nitrogen concentrations. The ammonia loading rate under these conditions
was 1,300 – 2,740 lb/day. Note that the minimum ammonia load value is affected by a dip in flow that
occurs when the flow EQ basins reach minimum low level.
CONCLUSIONS
To date, the WRF evaluation to control foaming and enhance nitrification stability has provided good
insight into the relationships between the variables that are involved in maintaining a balance in the
microbiological community in the WRF. Each wastewater treatment plant is unique and the responses to
process control approaches and adjustments need to be tuned to the specific conditions for each facility.
For this effort, key process data is necessary. On-line analyzers tied into SCADA provide an advantage to
the operations team to make informed process control decisions and to see the responses of the system
to these calculated adjustments.
While great improvements have been realized in the performance of the WRF through this evaluation and
progressive implementation of operational changes and control equipment, the WRF continues to adjust
the operation to optimize conditions. The approaching winter season will provide the first opportunity to
operate using the equalized ammonia nitrogen loading control system. The WRF staff awaits the
challenge of these conditions with greater understanding, more tools and higher confidence that improved
control of Nocardia foam and scum, and more consistent nitrification performance will be achieved.