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POLYMER ADDITION COMBINED WITH RAPID DECREASE IN SOLIDS RETENTION TIME IS AN EFFECTIVE NOCARDIA FOAM CONTROL METHOD

San Jose/Santa Clara Water Pollution Control Plant (SJ/SC WPCP)
San Jose, California

In this study, Nocardia foam control using a combination of polymer addition and solids
retention time (SRT) reduction was investigated at the San Jose/Santa Clara Water Pollution
Control Plant (SJ/SC WPCP). A three-week continuous polymer addition at increased dosing
rates of 0.35 mg/l, 0.5 mg/l and 0.75 mg/l reduced Nocardia foam coverage from 100% to less
than 5%. But, foam accumulation returned to 95% coverage when polymer dosing was stopped
for a week. It only took a week to eliminate Nocardia foam from the aeration tanks when 0.5
mg/l polymer addition was accompanied by SRT reduction from eleven days to four days. A
potential effluent ammonia permit violation associated with SRT reduction was avoided by
aerating the anoxic compartment of the aeration tanks and converting the step-feed biological
process to plug flow mode. Except an increase in secondary effluent solids concentrations during
plug flow operations, polymer addition to the return activated sludge (RAS) and Nocardia
wasting to the digesters via dissolved air floatation did not cause foaming in the digesters nor
was it detrimental to effluent filtration.


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Posted: May 20th, 2011 | Filed under: >1M, Waste Water Treatment | Tags: , , , | No Comments »