New plant technology to benefit environment
both pork processors and the environment, writes Anthony
Fletcher.
Agricultural Research Service (ARS) scientists and partners in the US claim that the system is capable of converting a site's brown wastewater lagoon into blue, clean and aerated water.
Soil scientists Matias Vanotti, Ariel Szogi and Patrick Hunt were so impressed with the system's performance during a recent year-long evaluation that a patent is now pending.
Minimising the impact of livestock waste on the environment is one of the sector's major challenges. With swine facilities, the problem is compounded when nutrient-rich waste is flushed into lagoons and then applied to cropland.
Problems arise when more nutrients are applied than crops or forage can use, causing excess nutrient runoff that can lead to poor drinking water and oxygen depletion in bodies of water. The magnitude of this challenge was clear during the evaluation of the system - at its operating peak during the trial, the system processed waste generated by more than 4,000 pigs. On average, 12,700 gallons of manure - containing 176 pounds of nitrogen - were flushed from the complex each day.
Environmental regulations on both sides of the Atlantic are becoming increasingly tighter, which has brought problems of pollution into sharper focus.
In order to deal with such waste and help processors achieve environmental targets, the system relies on a mix of technologies developed by ARS and companies in the United States, Spain and Japan. It comprises tanks and staging areas laid out over 200 feet and performs three critical processes in animal-waste management.
Firstly it separates solids and liquids from swine wastewater while recovering organic matter; it removes ammonia from wastewater, using acclimated nitrifying bacteria; and it transforms phosphorus removed from wastewater into a solid, marketable fertilizer while converting leftover effluent into an environmentally friendly liquid crop fertilizer.
"Results showed that this system can have a great impact in animal-waste treatment," said soil scientist and project collaborator Ariel Szogi.
The researchers tested the system's ability to eliminate animal waste discharge - and related release of ammonia, odours and pathogens - to surface and groundwater. They also gauged its ability to stem soil and groundwater contamination by nutrients and heavy metals.
During the evaluation, the system removed more than 97 per cent of total suspended solids from wastewater. It also stripped the water of 95 per cent of total phosphorus, 99 per cent of its ammonia and more than 97 per cent of its odour-causing components.
The scientists believe therefore theta their invention could help meat processors achieve greater environmental performance. "The innovation can soften the effect of the new demands regarding modern swine production and environmental sustainability," said soil scientist Matias Vanotti.
The evaluation, conducted by the inventors and private firm Super Soil Systems USA, was based on a full-scale version of the system built at a farm in North Carolina. Construction was part of an agreement between Smithfield Foods of Smithfield, Virginia; Premium Standard Farms of Kansas City, Missouri; and the North Carolina Attorney General's office to use environmentally superior technology to replace current waste lagoons.
The research is part of Manure and Byproduct Utilization, an ARS national programme.
