Perception vs Reality: How did college students’ perceptions change after visiting a hog farm?

As the divide between rural and urban communities becomes more pronounced, there are fewer people in North Carolina who know what it’s like to actually live around a farm. That’s one reason we wish the courts would have allowed juries to visit the farms being targeted in lawsuits — we know that when people visit a farm in person and get an up-close look at how it operates, they come away with a more favorable impression.

As for those who rely solely on media reports to inform their perception of hog farms… well, there’s no telling what they might think.

NC Farm Families recently invited a group of students from Mount Olive University to visit a hog farm in Duplin County and learn more about how our treatment lagoons work. It seemed like a good opportunity to see how perceptions change after visiting a hog farm, so we asked each student to complete a short survey before and after their visit.

UMO students walk the perimeter of a lagoon.

UMO students walk the perimeter of a lagoon.

The results were telling:

Nearly 75% of the students had a more favorable impression of hog farms and treatment lagoons after their visit. The other students’ perceptions remained the same.

When we asked students to rate the odor near the lagoons on a scale of 1-10 (with 10 being the strongest), they expected the odor to rank as a 6.6 before their visit. After the visit, they rated the odor next to the lagoon as a 2.5. Nearly two-thirds of them rated the odor as very faint (1 or 2).

An even higher percentage of students — nearly 75% — rated the odor on the farm in general as very faint (1 or 2). Perhaps that is why none of the students who visited said they would consider this particular hog farm a nuisance.

When we asked what surprised them most about their visit to the farm, many students focused on the lack of odor:

“Hog farms are much cleaner and safer than the media portrays.”

“The odor was not bad.”

“It smelled a lot less than I imagined… The media makes them seem terrible when they are actually well maintained and regulated.”

Our experience with these students reinforces what we’ve always known: When people actually visit a family farm and see how it operates, they are impressed with our farms and the dedicated people who run them.

Perceptions of hog farms changed after the students visited the farm

Perceptions of hog farms changed after the students visited the farm

Understanding Pig Lagoons: Everything You Need to Know

There are three key things to understand about lagoons: (1) How they are designed, (2) the anaerobic process that takes place inside lagoons, and (3) the benefits they offer to farmers. Let’s look at these separately:


Most lagoons are constructed as an earthen basin. They are earth-walled structures that use basin liners to prevent groundwater contamination. Lagoons must have a liner, which is typically made of clay or geosynthetic plastics.

Lagoons must meet specific design criteria. Everything from size to dike construction are carefully engineered to meet state regulations. It is far more complicated than just digging a hole in the ground. Just like a building must meet certain codes and regulations, so does a hog lagoon.

Where Can Lagoons be Built?

Another major aspect of lagoon design is the location. In North Carolina, there are many rules that say hog lagoons may only be built certain distance away from wells, only in certain soil types, etc. Along with placement of lagoons, the fields where waste water can be applied must be carefully placed (more on that later).One thing that many people don’t realize is that no new hog lagoons have been built in North Carolina for more than twenty years. The state legislature passed a moratorium on construction of new hog farms in 1997 and those restrictions remain in place today.


Lagoons may not seem very complicated, but there is actually a lot going on in that earthen basin. From anaerobic bacteria to pink water, lagoons require a closer look.

Anaerobic Process

The anaerobic process is where the magic happens in the lagoon. It is the process that occurs when anaerobic bacteria grow in an oxygen free environment (the treatment zone of a lagoon) and decomposes organic matter (waste). The result of this process creates something very valuable to the farmer — fertilizer! Those anaerobic bacteria do a great job of treating the waste and turning waste into useful nutrients that can be used as fertilizer.



Managing Lagoon Levels

Farmers must maintain a buffer of at least 19” between the top of the lagoon and the liquid storage. This space – called a freeboard – is designed to prevent the lagoon from overflowing.The lagoon system is built to effectively manage significant rainfall events. Maintaining a minimum freeboard level is specifically designed to handle 24 hours of rain during a 25-year storm – the largest storm that can be expected during a 25-year period based on historical record. If the freeboard level falls below 19 inches, the farm must immediately notify the NC Department of Environmental Quality (DEQ) and submit an action plan to return to normal levels within 30 days.

Pink Lagoons?

Color is a good indicator of proper lagoon function. The pink tint often seen on hog lagoons means it is working as intended. Purple sulfur bacteria reduce the concentration hydrogen sulfide, a significant source of odor. In other words, pink reduces stink.


Anaerobic lagoons produce nitrogen which is a valuable fertilizer for farmers. Farmers must follow a detailed process to properly manage their lagoons. Here’s how it works:

The farmer samples the surface water of the lagoon and sends it off for analysis every 90 days.  The results from that analysis tell the farmer how much plant available nitrogen is contained in the lagoon’s temporary storage depth. The farmer then applies the nitrogen to crops based on guidelines set by the DEQ. State regulations also require farmers to keep detailed records of the nutrients applied.

To simplify, the process looks like this:

the cycle

the cycle

Ultimately, it is a sustainable cycle that allows pigs to fertilize crops like corn which then gets fed back to pigs in their feed ration.