WASTE MANAGEMENT
PIH-62
pork industry handbook
COOPERATIVE EXTENSION SERVICE • PURDUE UNIVERSITY • WEST LAFAYETTE. INDIANA
Lagoon Systems For Swine Waste Treatment
Authors
John M. Sweeten, Texas A & M University
Clyde L. Barth, Clemson University
Ronald E. Hermanson, Washington State University
Theodore Loudon, Michigan State University
Reviewers
Frank Humenik, North Carolina State University
Don Jones, Purdue University
James Moore, University of Minnesota
Richard Smith, Iowa State University
Lagoon systems provide treatment of livestock manure and storage of treated products prior to final utilization or disposal on land. Lagoons designed and operated for destructive treatment (breakdown) of manure can reduce organic matter and nitrogen by more than 50%. In addition, lagoons can be designed and operated to provide ample storage of manure and wastewater to meet no-discharge requirements of state and federal water pollution control agencies and to fit cropping and labor cycles of the livestock feeding operation. Lagoons are also used to supply water for flushing in many swine operations.

Advantages and Disadvantages
Properly designed and operated lagoon systems for treatment and storage of livestock waste have many advantages. These include:
•	Compatibility with modern hydraulic cleaning and/or . pit overflow systems
•	Low cost construction
•	Maximum convenience in manure handling and land spreading
•	Minimum operating costs
•	Low labor requirement
•	Reduction or elimination of fly problems
However, there are also disadvantages in using lagoon systems. Some disadvantages are:
•	Appreciable loss of manure fertilizer value, especially nitrogen
•	Need for terminal disposal of effluent by irrigation
•	Need for periodic sludge removal
•	Possible formation of mosquito habitat
•	Cost of equipment and electrical energy where aerators are used

Also, odors, flies and groundwater pollution may result if the system is under-designed or poorly managed.
Lagoon systems are preferable to storage pit/tank wagon systems when insufficient cropland is available for
full utilization of manure as fertilizer, when large volumes of water are used for manure removal, and/or when labor is limited. Lagoons are not recommended for a site that has a porous subsoil or a high water table unless an impervious lining is installed. Lagoons are recommended only where adequate distances to property lines and residences can be established.

Types and Characteristics of Lagoons
Livestock waste lagoons act as digestion facilities in which three categories of bacteria—aerobic, anaerobic and facultative—decompose the manure organic matter. Aerobic bacteria require dissolved oxygen to survive. Anaerobic bacteria cannot survive in free oxygen. Facultative bacteria can grow with or without free oxygen in the liquid waste material.

Anaerobic lagoons are commonly used for livestock waste treatment. This type of lagoon can handle relatively high loading rates of organic wastes. However, anaerobic decomposition of livestock waste can result in the production and release of odorous compounds. Proper design and operation will lessen odor emissions. Lagoon volume and dimensions should be carefully selected. Relatively constant operating conditions for anaerobic decomposition should be provided by maintaining the proper water level and by discharging manure into the lagoon daily or as frequently as possible.

In aerobic lagoons, algae generate oxygen tnrough photosynthesis, which takes place where sunlight penetrates the water (upper 4-5 ft.). Oxygen diffusion also occurs by wind action across the surface of the water. Thus, a maximum water depth of 5 ft. is recommended. Aerobic bacteria produce little or no odor but much more sludge than anaerobic bacteria. A naturally aerobic livestock waste lagoon is generally impractical as the sole means of treatment because a very large surface area is required for oxygen transfer. Aerobic lagoons must have about two