Aeration basins
A million gallons a day of mill effluent, and a BOD figure that climbed every winter as the water cooled and biological activity fell away with it.
lower effluent BOD within a month of dosing
01The plant
A containerboard mill producing about a million gallons of effluent a day, treated through two extended-aeration lagoons of fourteen million gallons each and a three-million-gallon polishing lagoon, then discharged to the local publicly owned works.
02Before
Every winter the same thing happened. BOD and suspended solids climbed in the effluent as the water cooled, the mill could not absorb the swings in incoming load on top of that, and the receiving works felt both. Troubleshooting put the cause at water temperature: below about 10°C biological activity falls away, and the resident population simply could not keep up with what was arriving.
03Treatment
A blend selected for organisms that stay active in cold water, applied to the lagoons from January — the coldest point of the mill's year, and deliberately so.
Every result in this library was measured at an operating plant treating with one of the formulations SediLogic supplies, over the window stated above. It is a field result published as reported, not a controlled trial we ran.
04Method
Effluent BOD tracked against the pre-trial figure through the month that followed. The assessment that preceded it monitored dissolved oxygen at points across the basin, oxygen uptake rate, residual macronutrients and the microscopic picture, which together are what pointed at temperature rather than at loading.
05Outcome
Water temperatures stayed low into mid-March and the incoming load did not shift materially across the window, so the improvement did not simply arrive with the season.
06Limits
Only a percentage is published. There is no starting BOD, no closing BOD and no permit figure to read sixty per cent against, so how much of the mill's winter problem this actually solved is not established. That temperature held and loading did not move are the publisher's assertions rather than data shown. Nothing was left untreated, and neither the mill nor its location is identified, so none of it can be checked.
Only the volatile organic fraction of a sludge responds to any of this. Grit, sand, silt, mineral precipitates and plastics remain at any dose, here and everywhere else.
—What we would supply
Liquid is intended for systems with metered or poured dosing and organic load in the water column. Sinking solids are designed for settled bottom sludge.
The planner does not calculate quantities for an activated-sludge basin. Send the flow and loading for review. A lagoon dose table cannot be transferred to this application.
—Read next
Aeration basins
IndustrialImprovement inside 4 months
reported annual saving once settling recovered
Nine months of filamentous growth had taken the settled-volume test above 980 ml/L, so the clarifier could not hold solids and the plant was paying to haul them away.
Aeration basins
Municipal1 year
reduction in secondary sludge production
A food-processing load arriving at a municipal works, bringing enough grease with it to drive filamentous growth and cost the plant its settling.
Aeration basins
Industrial60 days
to clear the foam blanket
A stable foam blanket on the aeration basin, fed by grease in the incoming load and unaffected by the usual mechanical answers.
Your lagoon next
This result came from a different plant. Your sludge composition and operating conditions need their own assessment. Send us your lagoon details for a dosing review; do not use the quantity on this page as your application rate.
