Sustainably Treating Hog Waste

1. Sustainability Problem: Toxic Animal Farm waste

Raising animals from farm to fork takes an incredible amount of resources, including an enormous amount of water.  Agriculture worldwide accounts for 70% of water withdrawals.  In the case of animals, water must be used first to grow feed crops, and then to water the animals themselves as they grow.  Also, as climate change accelerates, access to clean fresh water is becoming more and more difficult.

The water used in the farms is contaminated with feces and other animal byproducts and collected in waste ponds, then released into waterways, often with insufficient treatment.  This contaminates water supplies used downriver for humans, crops, and other livestock.  It also means that water treatment must be more and more aggressive, requiring more energy and resources the further downriver you get. 

In North Carolina, where I am from, the primary source of this waste is from Hog Farms.  These farms also regularly have incidents of overflow during heavy rains, especially during the hurricanes that come through the state every couple of years.  Most of these hog farms are located in eastern North Carolina, the very place where the hurricanes make landfall and are their strongest, and also a very flat place that floods easily.  During these events often entire enormous waste ponds will be compromised and all of the contents flood downriver, contaminating entire towns with toxic floodwaters, causing illness and death.

2. Sustainable Technology: Advanced Oxidation Technologies (AOTs)

This technology separates wastes from water, and treats them to create a solid odor and pathogen free fertilizer.  So not only is it cleaning the water, it is creating a useful product!  First, an additive is added to the waste.  Then it is sent through “The AOT reactor and ozone diffusion”.  Then it goes through a process called flocculation, which accumulates all the waste into larger and larger pieces which are much easier to remove from the water stream.  These solids are separated by centrifuge, and then dried.  Then hey presto!  Fertilizer! 

This can be done constantly as it is created so that waste is not left for long periods in holding ponds, eliminating the hazard of storing toxic waste in unsafe spaces. 

3. Stakeholders:

  • Hog Farmers
  • Chicken Farmers
  • Cattle Ranchers
  • Other animal farmers
  • Fishing industry
  • Any life in the rivers (fish, shellfish, etc.)
  • All humans that use rivers as their source of water
  • Cities that pull water from rivers and have expenses in wastewater treatment
  • Recreational water users (boaters, beach swimmers near river outlets, etc.)
  • Coastal ecosystems and estuaries (hog waste also causes algal blooms)

4. Technology Implementation:

1. Hog Farmers are already paying for wastewater treatment technologies which are not as effective, and are being fined for their environmental discharge.  These farmers are relatively wealthy, and would likely be able to invest in this technology if the amount above and beyond current efforts will pay for itself in reduced fines.  There would also be a marketing bonus for products produced at the farm to be marketed to the “green” consumer market.

2. Cities which draw water from rivers have an economic interest in those rivers being cleaner.  So local and state governments may be convinced to put money into a fund to help subsidize the implementation of these systems.

3. Ideally this would be implemented at the farms most upriver, to be able to analyze most effectively the change in water quality of the farms’ effluent and its effects on the river, instead of trying to accurately measure the amounts of contaminants further downriver where many farms have contributed to the problem.



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