Aeration basins
A food-processing load arriving at a municipal works, bringing enough grease with it to drive filamentous growth and cost the plant its settling.
reduction in secondary sludge production
01The plant
A municipality's activated-sludge works taking about 5 MGD, with a food-processing load arriving in the influent.
02Before
Grease in the incoming flow was high enough to favour filamentous growth in the biomass, and the works had lost its settling. Polymer went in continuously to hold it. Secondary sludge production was high and expensive to deal with, the filter-pressed cake came off at fifteen to seventeen per cent solids, and 1,500 cubic feet of grease stood in the scum pit with about another thirty-five arriving every week — all of it lifted out by hand and hauled to landfill.
03Treatment
A biological powder blended for high-grease influent, applied across a full year with the stated objects of a healthier biomass, less secondary sludge, better settling and no standing grease.
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
Twelve months of the plant's own records read together — effluent suspended solids, polymer consumption, secondary sludge production and the solids content of the pressed cake — alongside the operators' observation of the scum pit.
05Outcome
The grease accumulation was visibly degrading about a month in and had gone two months after that. The works also reported running better through cold weather, which it attributes to the change in the biomass rather than to anything it did differently.
At the start
Effluent suspended solids 12–16 ppm with polymer dosed continuously to hold settling, pressed cake at 15–17 per cent solids, and 1,500 cubic feet of grease standing in the scum pit.
At the close
Effluent suspended solids under 5 ppm, polymer use halved, cake 25 per cent drier, secondary sludge production down 20 per cent, and the scum-pit accumulation gone.
06Limits
A year is a long window and nothing was left untreated across it, so twenty per cent is a before-and-after at one works rather than a controlled result. No incoming grease concentration is published, which means there is no way to tell whether the load itself changed: a food-processing discharger altering its own practice would move every number on this page. 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.
—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
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
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.
