22 Jan 2021

Processing plant wastewater as potential irrigation source for crops

Gestão da Água

Auburn University College of Agriculture researchers were encouraged to find alternative water resources for crop irrigation. The driving force behind this project was the dwindling global fresh water supplies as well as the ever-increasing population.

“One proven source that can meet this demand is wastewater,” according to Brendan Higgins, assistant professor in the Department of Biosystems Engineering and head of the research team. “In addition to providing water for crops, wastewater resources are rich in nutrients, specifically nitrogen and phosphorus. Combined, these nutrients can improve the growth of food crops.”

A four-year grant worth $499,577 has been afforded by the National Institute of Food and Agriculture (NIFA) to Higgins and his research team to study the possibility of using poultry processing wastewater for irrigating in controlled-environment agriculture.

The team consists of Daniel Wells, assistant professor in the Department of Horticulture; Dianna Bourassa, assistant professor and extension specialist in the Department of Poultry Science; and Rishi Prasad, assistant professor and extension specialist in the Department of Crop, Soil and Environmental Sciences.

The poultry industry generates a significant amount of wastewater packed with nutrients. “This water supply is currently being treated as a waste at a significant expense to industry and, ultimately, to consumers,” Higgins said.

In 2018, the U.S. broiler industry produced about 9 billion chickens, bolstering the economy by $31.7 billion. This also led to a 62 billion gallons of wastewater to be produced annually by the processing and meatpacking plants; at a staggering treatment cost of more than $247 million.

“Repurposing this water supply for use in crop production has the potential to significantly reduce treatment costs, increase food production and reduce the overall impact on the environment,” Higgins said. “However, there are three main challenges that need to be addressed in order to safely and efficiently use wastewater for food production.”

The first challenge is that the nutrients mentioned should be in the adequate form to provide sustenance to the crops. Secondly, the water must be free of pathogens, and, lastly, significantly reduce the negative effects of antimicrobial chemicals found in the poultry wastewater.

The researchers will meet the project’s goal via four major focus points:

  1. Developing a novel wastewater treatment reactor that uses algae and bacteria in tandem to both clean the water and transform the nutrients into usable forms for the crops.
  2. Testing the ability of said reactor, along with other non-chemical treatment methods, to clean the water of pathogens and render it safe for crop irrigation.
  3. Growing lettuce as means to test the system’s performance. During this step, researchers will dose in antimicrobial chemicals into the treatment system to determine how effectively it removes and mitigates their negative impact on lettuce production.
  4. Developing a set of engineering models based on this system that will serve as a foundation for a “scaled up” version that can be safely deployed and effectively used at commercial poultry processing plants.

According to Higgins, the treatment system will need to be located near a processing plant. “Water can be pumped a significant distance, but of course you would need to consider the site-specific economics,” he said. “Where is the supply and demand, and does it make sense for this particular location?

“One of the attractions of controlled-environment agriculture is that the footprint of the facilities is quite small, given how intensive the crop production is. You can produce a lot of lettuce on a small area of land using greenhouse technology. It is conducive to suburban and exurban areas where a lot of the poultry processors are located.”

“I’ve been working with poultry processing wastewater over the past few years and have been developing the idea that algae can be used to overcome the negative consequences of antimicrobial agents in the poultry processing wastewater,” Higgins said. “However, it wasn’t until our research team started talking that this idea of growing crops with wastewater really came to fruition.”

While lettuce will be the focal crop of this project, Higgins sees the potential for using wastewater on a variety of crops. “Non-food crops like cotton would probably be easiest from a regulatory standpoint,” he said. “However, we really wanted to grow food with the water because it is a major research challenge. There are already many options for reutilizing waste materials on non-food crops and forage.”

Source: https://www.hortidaily.com/article/9285150/us-al-studying-poultry-wastewater-as-way-to-irrigate-crops/




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