sustainability

Pig farmers reduce environmental impact | Activists push back

Greenhouse gas emissions (GHG) are a national (and global) concern, with blame being directed everywhere from fossil fuels to cow farts. Included in the blame game, at least in North Carolina, are pig farms.

Terms like “toxic,” “polluters,” and “cesspools” have been used to describe pig farms in North Carolina. According to activists, they really have a problem with how we handle manure. They view the lagoon and spray field system as an “antiquated” method that needs to be abolished. Activists have sued over “odor” and effectively shut down several farms. In these lawsuits, they never requested a change in the system (just millions of dollars) but did highlight alternatives that could be implemented.

Fast forward to recent months. Farmers have been working together with Dominion Energy and Smithfield Foods to implement years of research to cover lagoons, capture methane, and turn it into renewable natural gas, which in turn, produces electricity. Note, this was one of the alternatives encouraged by activists in court. Now they oppose it, with claims that it may make things worse.

Confused? Get ready to become more so.

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Greenhouse gas emissions in America are caused by several things, the least of these, though is agriculture. According to the EPA, only 10% of GHG are caused by agriculture, with less than 4% caused by livestock. Swine emissions come in at a whopping .4% of total GHG emissions. That’s less than half of a percent.

Yet, .4% is not low enough. They want you to stop eating bacon for four-tenths of the total GHG emissions. Seriously.

Even so, hog farmers and the pork industry are actively working together to reduce that less than half a percent even further.

It gets better. According to the EPA, emissions can be reduced by:

  • Controlling the way manure decomposes to reduce nitrous oxide and methane emissions.

  • Capturing methane from manure decomposition to produce renewable energy.

  • Storing manure in anaerobic lagoons to maximize methane production and then capturing the methane to use as an energy substitute for fossil fuels.

Did you catch that? The EPA suggests capturing methane to produce renewable energy—the exact thing pig farmers are trying to do in North Carolina. But activists still oppose this EPA-recommended tactic. The EPA says, “Capturing methane and using it as an energy sources has a positive impact on the environment, as it avoids methane emissions and displaces conventional fossil fuels.”

Do you know what else the EPA recommends to reduce GHG emissions? “Fertilizing crops with the appropriate amount of nitrogen required for optimal crop production.” North Carolina pig farmers are required to test the nitrogen content of the manure they spread on crops before application to make sure they are not just following North Carolina regulations, but also following EPA recommendations.

The bottom line: activists are blaming us for GHG emissions, while also preventing us from reducing our impact. (We’re confused, too.)

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What we do know is that farmers have been doing more with less for a long time. The U.S. swine industry has decreased emissions by 18% since 1990, largely in part because of their determination to always improve and willingness to adopt new technology. Over the past 17 years, North Carolina hog farmers have significantly increased their feed efficiency, resulting in reductions of nutrient content in manure lagoons at farms by 35%-78% and ammonia level reductions of 22%-54%, according to NPPC.

Let’s stop blaming pig farmers (or any farmers) for being the cause of all the GHG emissions. You know the old saying — when you point a finger at someone, there’s three more pointing back at you.

Activists should remember that, especially when flying around in their airplanes to take photos of pig farms. Transportation is the largest contributor to GHG emissions in America and aircraft rank near the top of the list. Who’s the real polluter here?

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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:

LAGOON DESIGN

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.

HOW A LAGOON WORKS

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.

process2

process2

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.

BENEFITS TO FARMERS

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.