Treating Biosolids With Microwaves

One of the challenges of treating biosolids is how to efficiently remove heavy metals to make it safe enough for use as organic fertilizer. If not filtered out adequately, these potential toxins can leach into the environment. Extracting these metals are expensive and can hinder the wider adoption of biosolids as a viable source for agricultural use.

The presence of heavy metals in biosolids have always been a concern in their application to soil because these metals can be absorbed by plants and can end up contaminating the food supply of the community. Accumulation of these metals in the human body can lead to intellectual disability in children, dementia in adults, central nervous system disorders and damage to organs.

Researchers from Florida State University have examined new ways of removing these heavy metals simply by running it through a microwave. It was successful in eliminating three times the amount from biosolids compared to traditional means and could potentially save treatment plants up to 60 percent in cost.

This opens the possibility of producing more organic fertilizer for cultivating crops that are safe for human consumption. It would also reduce the contamination of heavy metals in the water from runoff.

Gang Chen, a professor of Civil & Environmental Engineering at the FAMU-FSU College of Engineering said, “Biosolids are a valuable resource, but heavy metals prevent their use.”

This study is significant because there is an exponential increase in wastes produced by an ever-growing population and the biosolids produced would need to be optimized for fertilizer use. Treating biosolids can be challenging. The traditional way of getting rid of unusable biosolids was to dispose of it in landfills or incinerators which are not only costly but are also a cause of secondary pollution.

Chen’s team studied the type of energy needed to develop a more efficient process of treating biosolids. They also investigated the amount of energy that was necessary to break the bonds that attached the heavy metals to the rest of the biosolids, but without destroying the material itself. After surveying the electromagnetic spectrum, Chen’s group discovered that the radiation held the right amount of energy.

Microwave radiation checked all the parameters they were looking for. They ran a sample of biosolids in a microwave and they were able to remove the heavy metals from biosolids using a lower dosage of treatment chemicals than what traditional extraction required.

“It’s a technique that can be scaled up to facilities that service a city or a region to give them a less expensive way to make biosolids safe,” Chen said.

Breakthroughs like these are what could make a big difference with how biosolids will be used in the future. As more effective ways of treating biosolids are discovered, the potential to develop renewable fertilizer that is sufficient for food crops on a much wider scale is a game-changer. It would make food production more affordable and would have a reduced environmental impact. Chen and his team hope to bring this discovery to more countries for early adoption.

If you are a municipality in Ontario and in need of a biosolids management solution, please feel free to contact us at 1 (877) 479-1388.


Treating Biosolids With Microwaves
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