Page 11 - SIMPLIFIED WASTEWATER TREATMENT FUNDAMENTALS \ Advanced Activated Sludge P1

Growing the Ideal Species

Microorganisms are cold blooded, meaning they grow faster and work

harder when it’s warm, and grow and work slower when it’s cold.

Each microorganism species has a specific growth rate and lifespan. The

experienced Operator knows the growth rate for the ideal species

depending on the time of year.

Sludge Retention Time (SRT) for carbonaceous removal (not to be

confused with species associated with nitrogenous nutrient removal)

may be 2 to 6 days in the summer season and 10 to 20 days in the winter

season. This varies widely by climate and location.