Lagoon Aerators

Surface and diffused aeration equipment for wastewater lagoons, with the selection guidance that decides which family fits your cells.

Short answer

Lagoon aerators come in two families: floating surface units that transfer oxygen at the top of the water column, and diffused systems that push fine bubbles up from the bottom through a shore-mounted blower. Choose on cell depth, climate, energy cost and sludge history, and size on pounds of BOD5 applied rather than acres.

What we carry

Kasco

Floating Surface Aerator

Floating surface aeration for wastewater lagoon cells, sized by organic load. Quoted to your site with freight and power service accounted for.

Quoted to your siteFreight4 sizes

Most aerator listings are a grid of horsepower ratings with no way to tell which one belongs on your cells. The selection logic below is the part that actually matters, and it comes straight out of the aeration guide.

Start with the two families

Floating surface aerators transfer oxygen by contacting water with air at the surface. Lower upfront cost, fast installation on mooring lines or cables, and relocatable as loading shifts. They use more energy per pound of oxygen delivered, mix mainly the upper water column, and splash-style units are exposed to icing.

Diffused aeration puts a blower on shore and fine-bubble diffusers on the bottom. Best energy efficiency in most applications, often around half the power of surface aeration for the same duty, with full-column mixing that suppresses sludge zones and reliable winter operation. Higher upfront cost and a more involved installation.

Selection by duty

Your situation	Points toward
Shallow cells, tight budget, fast install	Floating surface
Deep cells, sludge blanket building	Diffused fine bubble
Hard-freeze climate, winter ammonia trouble	Diffused fine bubble
High energy rates, continuous run hours	Diffused fine bubble
Loading is changing, may need to relocate	Floating surface
Summer peaking capacity on top of a base system	Floating surface
Single-cell system with no redundancy	Multiple smaller units over one large one

Size before you shop

There is no per-acre shortcut that holds up. Two five-acre cells with different BOD loads can need very different horsepower. Get a current loading calculation first, then run the sizing calculator for a planning-level range. On a permitted municipal system, your state design standards and a licensed engineer have the final word.

Compare on tested transfer, not horsepower

Published design references rate floating high-speed surface aerators around 1 to 1.2 kilograms of oxygen per kilowatt-hour, with larger low-speed units reaching roughly 2 to 2.5 kg per kWh. Those are category patterns, not product specs. When you compare two units, compare their tested oxygen transfer numbers, because that is what converts energy into treatment.

Common questions

How do I know what size aerator I need?

Oxygen demand follows pounds of BOD5 applied per day, not surface acres. Design references commonly size oxygen supply at roughly 1.5 pounds of oxygen per pound of BOD5 applied, and in partial-mix cells the horsepower needed to keep the cell mixed often controls the design instead. Run the sizing calculator for a planning range, then confirm with an engineer.

Why is everything quoted rather than priced online?

Aeration equipment ships by freight and the delivered cost depends on your site, your power service and your install. Quoting it means the number you get is the number you pay, rather than a list price plus a freight surprise.

Can you help me choose before I buy?

That is the point of the guides here, and we run loading numbers with operators by phone at no charge. Send us your current BOD and flow data and your cell dimensions and we will work through it with you.

Read before you buy

Aeration