Common polymers used on construction sites and irrigation fields to reduce soil erosion also can help treat water from livestock lagoons, according to
The polymers, called polyacrylamides — or PAMs — are relatively inexpensive chemicals that the soil absorbs, which then helps bind soil particles. They have no significant movement below the root zone and they degrade over time, not affecting water quality in streams.
Todd Bolte, an undergraduate researcher at the time, combined PAMs with other chemicals to test for improved water quality using effluent from a dairy farm.
The study compared the traditional method of using sand, PAMs and chemicals including aluminum sulfate, ferric chloride and calcium oxide. Bolte found the combination of PAM and calcium oxide proved most effective in reducing nitrogen, ammonia, phosphorous and fecal coliform concentrations.
Since PAMs can cause suspended solids to clump, perhaps they also can be used to collect nutrients, says Allen Thompson, associate professor of biological engineering.
“The bottom line is that this approach shows promise,” Thompson says. “It would be done as a polishing agent in conjunction with other treatment systems to take the load off other treatment methods to help meet state regulations. You still have to have some way to get your solids out of the lagoon.”
This method could be used in human systems as well as animal-waste systems, he adds.