Aeration basins
Effluent ammonia above what the plant's permit allowed.
reduction in effluent ammonia
01The plant
A chemical works' own activated-sludge plant, 7,600 m³ a day (2.0 MGD), designed for nitrogen removal, with anoxic nitrate removal in a basin fed by return sludge and part of the mixed liquor. Influent ammonium runs 200–800 ppm.
02Before
A plant upset took the nitrifying population out. Effluent ammonium went past 400 ppm and the works was in acute breach of its discharge permit. Basin pH had fallen to 6.1–6.5 — not what caused the loss, but low enough to obstruct a recovery, because nitrification consumes alkalinity as it re-establishes and a restart at that pH could have driven it under 6.0 and stalled there.
03Treatment
Nitrifying cultures seeded into the aeration basin across ten days, with caustic soda dosed over the same period to lift pH and alkalinity into a range that would let the population hold.
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.
04Sizing
A ten-day seeding rather than a single charge, against the basin — and paired with an alkalinity correction, because seeding into water that cannot hold its own pH wastes the seed.
05Method
Effluent ammonium and effluent nitrate tracked through the ten days, against the works' own operating record from before the upset.
06Outcome
The mixed liquor was allowed back down to the 6.5–7.0 that had always supported nitrification there, so the caustic dosing did not have to continue.
At the start
Effluent ammonium 397 ppm, mixed liquor pH 6.1–6.5, works in breach of permit.
At the close
Effluent ammonium 10 ppm, a 97.5 per cent reduction. Effluent nitrate rose from zero to a peak of 135 ppm and then eased to 101 as denitrification caught up with it.
07Limits
Two things changed at once and the record is open about it: cultures were seeded and pH was raised across the same ten days, and pH alone can restart a nitrification that has been inhibited rather than lost. That the low pH was not the cause of the loss is the plant's assessment rather than a measurement. Nothing was left untreated and the works is not named.
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.
Nitrifying organisms do not survive drying. No product in SediLogic's dry range addresses an ammonia or total-nitrogen permit, and this record is published as part of the field record rather than as an offer.
—What we would supply
SediLogic Liquid is the article in the range that reaches this — a concentrate for systems that take a metered or poured dose rather than a solid one, which is what a basin under continuous flow is. Nothing in the dry range is the right vehicle for mixed liquor: a sinking solid is built to leave the water column, and mixed liquor is the water column.
SediLogic holds a written dose table for wastewater lagoons and for no other duty, so the planner will not size a basin. A quantity for one is settled with a person against your flow and your loading.
—Read next
Aeration basins
IndustrialOne month from a January application
lower effluent BOD within a month of dosing
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.
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.
Your lagoon next
A different plant, a different loading and a different sludge. What decides your result is how much of your own accumulation is organic and treatable, and whether the dose is sized against the lagoon in front of us rather than read off this page. Tell us the dimensions and we will size it.
