Wastewater lagoons
A fat, oil and grease cap covering the whole lagoon surface, cutting oxygen transfer into the water beneath it and standing between the plant and its irrigation discharge.
surface coverage by the grease cap, in three weeks
01The plant
A 22 million gallon food-processing wastewater lagoon taking about 50,000 gallons a day.
02Before
A fat, oil and grease cap six inches thick covered the whole lagoon surface, cutting off oxygen transfer and holding back nitrogen removal, which in turn limited what could go to land irrigation. The lagoon was being dredged on a regular cycle.
03Treatment
An opening dose in June followed by weekly doses through to September. The surface aerators were removed for the treatment period, so this ran without aeration.
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
The opening charge was set against the lagoon's volume and the weekly doses that followed against its weekly flow — volume for the standing problem, flow for what kept arriving. Both are bases rather than rates, and the quantities are not carried here.
05Method
Photographs of the cap for coverage and thickness, effluent nitrogen measured, and accumulation depth taken with a sludge judge.
06Outcome
The plant reported 75 per cent less material requiring dredging and better irrigation capacity as nitrogen came down.
At the start
Grease cap over 100 per cent of the surface at about six inches thick.
At the close
Coverage down to 60 per cent and thickness to about two inches, within three weeks.
07Limits
Cap coverage and thickness were judged from photographs, which is not a measurement. The 75 per cent dredging figure has no before-and-after tonnage behind it. Aerators were removed during the window, changing the lagoon in a second way at the same time. No untreated comparison and no laboratory analysis.
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
This is the duty SediLogic supplies and sizes. Which article depends on where the material sits: Sedivore Spike is the denser solid and carries down through depth to an established blanket, Sedivore Puck is a smaller unit that spreads a calculated dose across the bed, and SediLogic Maintain is a soluble pouch for load carried in the water column — with Sedivore Polar for that same duty where the water runs cold enough to stall a standard blend.
A quantity for your own lagoon comes from the dosing planner, sized against your dimensions and loading from the manufacturer's written dose method. It does not come from the figure on this page, which was set for a lagoon that is not yours.
—Read next
Wastewater lagoons
Industrial2 months
reduction in oil and grease
A lagoon carrying a heavy oil and grease load on top of an organic load, with the surface closed over.
Wastewater lagoons
Municipal24 weeks
of accumulated solids digested
Just over five feet of accumulated solids in the primary aerated lagoon, assessed at 2,365 dry tons. The plant wanted a route that did not involve dredging.
Wastewater lagoons
MunicipalFive months, May to October
reduction in solids volume overall
Accumulated solids across two lagoon cells, against a specification calling for a 50 per cent reduction. The treatment window was bounded by water temperature, which has to stay above roughly 55°F for the organisms to work at all.
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.
