MANURE STORAGE - LAGOONS

Anaerobic	Single-Stage
Aerobic	Multi-Stage

Anaerobic Lagoons

Anaerobic lagoons are the ones used most commonly used to treat livestock manure because they are much less expensive than aerobic ones. These lagoons can be deeper since anaerobic processes do not require free oxygen. This permits a smaller surface area (and thus less odor emission) for a given lagoon volume.

Advantages of Anaerobic Lagoons

Anaerobic lagoons require relatively small design volumes and are thus less expensive to construct.
Anaerobic lagoons can decompose more organic matter per unit volume than aerobic lagoons.

Disadvantages of Anaerobic Lagoons

Anaerobic lagoons are sensitive to sudden changes in temperature and loading rates and will produce some septic odors as a result. However, serious odor problems seldom occur if the lagoon is designed and operated properly.
Anaerobic lagoons work best during summer and in areas without cold winters since higher temperatures improve manure decomposition.

Aerobic Lagoons

Aerobic lagoons are generally considered uneconomical for livestock manure treatment. These lagoons are usually shallow since aerobic processes require free oxygen. The oxygen is suppled either from the atmosphere by means of mechanical aeration or from algae as a result of the photosynthetic process.

Advantages of Aerobic Lagoons

Aerobic lagoons produce fewer offensive odors than anaerobic lagoons.
Mechanically aerated lagoons require only about half of the design volume of anaerobic lagoons.

Disadvantages of Aerobic Lagoons

A very large land area is required for naturally-aerobic lagoons since they must be shallow (less than 5-6 feet). Therefore, naturally-aerobic lagoons are very expensive to construct and impractical for livestock operations.
Mechanically aerated systems are too expensive to install and maintain for most livestock operations.
It may be necessary to add bicarbonates in order to maintain the pH between 6.5 and 9.0.
The efficiency of aerobic lagoons decreases during periods of cold weather since the rate of organic decomposition decreases as temperature decreases.

Single-Stage Lagoons

Single-stage lagoons are similar to earthen basins, but are designed to treat manure as well as for manure storage.

Multi-Stage Lagoons

Multi-stage lagoons work well for livestock manure treatment, especially when the treated manure will be used for irrigation or recirculation in a flush-type handling system. The first cell, or stage, is usually deep and anaerobic.

The level in the first state remains constant so that any additions will cause some of the treated effluent to overflow into the second cell, which is usually shallower. A multi-stage lagoon typically has fewer odors and organic solids than a single-stage lagoon. Three-stage lagoons are sometimes used where flush water is returned to the building for manure removal. Water is recycled from the constant-head second stage with the third stage used as a holding unit before irrigation onto cropland.

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