Manure Lagoon
Definition
What 'Manure Lagoon' means
Manure lagoons are large, uncovered pits used to collect and store urine, feces, and wash water from concentrated animal feeding operations. They emit methane and ammonia, and can overflow or leak, contaminating groundwater and surface waters with nitrogen, phosphorus, and pathogens.
In depth
The longer answer
A manure lagoon is an engineered, open-air basin designed to store liquid animal waste, primarily from industrial-scale pig, dairy, and poultry operations. It is essentially a large, earthen pond lined with clay or synthetic material to prevent seepage. The reader encounters these lagoons as the most common waste-management system on concentrated animal feeding operations (CAFOs), where thousands of animals are housed in confined spaces.
In practice, manure lagoons function as anaerobic digesters without the gas-capture equipment. Animal waste, urine, wash water, and feed spills are flushed into the lagoon, where bacteria break down organic matter in the absence of oxygen. This process releases methane, ammonia, hydrogen sulfide, and other gases. Over time, solids settle at the bottom, while the liquid layer is periodically sprayed onto nearby cropland as fertilizer, often exceeding the soil's nutrient-absorption capacity.
For consumers, manure lagoons matter because they are a major source of water and air pollution near factory farms. They can leak, overflow during heavy rains, or breach catastrophically, contaminating groundwater and surface water with pathogens and nitrates. The nuance is that while some farms use covered lagoons to capture methane for energy, the vast majority remain uncovered, contributing significantly to greenhouse gas emissions and local odor nuisances.
At a glance
Quick facts
| Detail | What to know |
|---|---|
| Primary use | Storage of liquid animal waste |
| Typical size | 1 to 20 acres in area |
| Key emissions | Methane, ammonia, hydrogen sulfide |
| Regulation status | Limited federal oversight in US |
In practice
What this means for you
- When buying meat or dairy, look for labels indicating pasture-raised or grass-fed, which generally avoid lagoon systems.
- Check your local watershed maps to see if your drinking water source is near CAFOs with manure lagoons.
- Support policies that require covered lagoons or alternative waste treatment, such as anaerobic digesters with methane capture.
- When visiting rural areas, avoid swimming in or drinking from streams near large livestock operations, especially after heavy rain.
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