Minnesota Lagoon Odors Neutralized

A central Minnesota plant was forced to find a new aeration solution when its existing system proved inefficient and expensive. Thankfully, the Mazzei Injector aeration system proved to be precisely what the facility needed.

A large vegetable processing facility in Sleepy Eye, Minn., was experiencing problems with its lagoon surface aerators. The company’s treatment process includes a collection and screening assembly, two an- aerobic stabilization ponds and a 40 million gallon aerated lagoon. The lagoon is used for BOD reduction and polishing before the water is discharged to a nearby creek. Several surface aerators had been used to provide the oxygen in the lagoon. However, the surface aerators were beginning to fail, and this caused odor issues. This, along with ongoing maintenance requirements, prompted the company to seek a new method for lagoon aeration.

In 2004, the plant maintenance supervisor began replacing the surface aerators with the Mazzei Injector aeration system. Since then, as the surface aerators have failed, they have been replaced with banks of eight Mazzei Injectors and subsurface nozzles; a 40 hp pump powers each bank of injectors. These systems deliver ample oxygen transfer and have provided the plant’s maintenance team with a solution to its lagoon aeration problem.

When comparing the Mazzei system to the old equipment, the maintenance supervisor said that the surface aerators are “less reliable, [they require] more maintenance, and you need a boat to get out there in order to fix them, which becomes a safety issue.”

The maintenance supervisor describes the Mazzei aeration system as “much better than the floating surface aerators,” noting that “since the equipment is all land-based, and the only piece of equipment with moving parts is the pump, we are much happier with this system.”

As the last remaining surface aerators fail, and the plant experiences growth in production and in wastewater loading, the company plans to install additional banks of the Mazzei equipment.