Management and Startup of Anerobic Lagoons

Proper management of a lagoon is critical for minimum odor levels. A new lagoon should be half filled with fresh clean water. Add waste slowly and gradually increase to the normal loading rate over a 2 to 4 month period. This gradual increase in loading will generally occur as the animals grow. Loading should be started in the spring or early summer to allow for bacterial action during the warm summer months. Load the lagoon daily or weekly. If the pH of the lagoon falls below 6.7, add hydrated lime or caustic soda.

A well managed lagoon will require sludge removal every several years. Removal of some of the solids every two to three years can greatly reduce problems associated with solids buildup and odors.

Try to avoid pumping the lagoon down in early winter. If the the bacteria do not have time to repopulate before cold weather arrives higher odor levels may result during the following spring. If excessive odors occur during the spring warm up period, agitation will reduce the time to equalize the temperature of the waste from top to bottom. Although this will not reduce the odor level, it will shorten the time of high odors.

Color is a good indicator of proper lagoon function. As the microbial activity of a new lagoon stabilizes the color will change from light green, to dark green and then to brown. This color change will often take a year. Swine lagoons will often develop a pinkish tint as a result of purple sulfur bacteria. These bacteria are desirable because they control the hydrogen sulfide concentration which is a significant source of odor. A black color or a grainy scum layer is an indication of overloading. These lagoons may have an unpleasant odor, and sludge will build up at a high rate. Once the sludge layer occupies a large portion of the treatment volume foul odors will be a common occurance.

As the water level of the lagoon rises, pumping will be required to prevent a spill or discharge. Lagoons should never be pumped below 4 ft of depth or low enough that solids are exposed (except during solids removal). The effluent is high in plant nutrients and must be applied to crop, forage, or forest land at agronomic rates.

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Return to Management of Odor and Sources Return to Odor Control Return to The Land Application of Animal Manure.

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