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.