California Carrot Plant Combats Fetid Lagoon

Grimmway Farms is one of the largest producers of carrots in the world, and when its Kern County, Calif., packing plant was faced with an aeration problem in its lagoon, it turned to Mazzei products for help.

The plant was having severe odor problems due to septic conditions in its truck washout water holding lagoon. In addition, low nutrient and nitrogen levels in the wastewater compromised its usefulness for crop production.

The plant’s manager selected a Mazzei AirJection aeration system as a cost-effective method of lagoon aeration. The aeration system consisted of a common, pressurized water line and featured model 4091 injectors spaced around the lagoon’s perimeter. Each injector discharged into a drop leg that terminated in a tee with 45-degree elbows and a set of N45 nozzles.

The AirJection system was introduced in September 2001. The angular placement of the gas-mixing nozzles at the end of each injector created a counterclockwise movement within the lagoon. After two weeks of operation, the septic lagoon became aerobic; black sludge turned brown and objectionable odors disappeared. Biochemical oxygen demand and total nitrogen fell, and the wastewater in the lagoon met regulatory compliance for land applications. The success of this pilot program led to a permanent installation that remains in operation today.