The aerated lagoon

An operator reference for aerated lagoons, with a season simulator: summer, winter and spring melt, one aeration lever, and six field scenarios.

At simulator.beedy.ca/lagoon/. No account needed; free.

What it is

An operator reference for aerated lagoons, with a season simulator. It suits small municipal systems and anyone learning how lagoons behave through a northern year.

The simulator

1. Pick a season: Summer (design flow), Winter (ice, deep cold) or Spring melt (overload).
2. Set the one lever an operator really has: the aeration power running.
3. Press Run the season and read the gauges: water temperature, detention time, dissolved oxygen in the first and third cells, BOD₅ in and out, removal, aeration energy, and compliance with a 25 mg/L BOD₅ limit.

The goal: keep dissolved oxygen above 2 mg/L in every cell and effluent BOD₅ under 25 mg/L, without wasting energy.

The reading

Seven short chapters: the process, the biology, nitrogen, phosphorus, temperature and winter, lab and control (the field tests an operator does and what goes to the accredited lab), and six scenarios written as symptom, action and what not to do: winter cold collapse, spring washout, summer algae, septic lagoon, short-circuiting, seasonal start-up. A glossary with sources closes it.