A growing challenge with proper sewage treatment has been the effective elimination of medicines and personal care products (PCPs) from wastewater. Many treatment plants have employed a variety of methods for removing these contaminants but with mixed results.
Although the technologies that could ensure proper sewage treatment are available, the appropriate technological upgrades that could effectively filter medications and PCPs are prohibitively expensive.
Diana Aga, professor of chemistry at the University of Buffalo, is studying the most effective methods among the 10 current modalities that are currently used today. She has identified two that work particularly well, granular activated carbon and ozonation. These two methods are a good solution for proper sewage treatment and have reduced the concentration of pharmaceuticals in water by more than 95 percent.
The industry standard for treatment has been activated sludge, which is very effective in removing nutrients such as nitrogen and phosphorus, but is not that effective in removing persistent drugs, including certain antidepressants and antibiotics.
Aga believes that the best way for treating wastewater from pharmaceuticals is to use a “multiple treatment process.”
“Our study shows that highly persistent pharmaceuticals that are not typically biodegraded in conventional activated sludge systems can be removed using ozonation,” she explained. “However, to reduce potential ecotoxicity of the treated effluent after ozonation, activated carbon may be necessary after ozonation.
Therefore, the concept of multiple barrier treatment is important in the system design if the ultimate goal is to use the reclaimed water back into potable use,” says Aga.
Potable water is the holy grail of water treatment. An Advanced Water Purification Facility (AWPF) is being built in El Paso, Texas that will make it the first in the nation to distribute treated wastewater directly to a city’s drinking water distribution system. It is expected to produce up to 10 million gallons per day of renewable, drought-proof water to supplement the city’s drinking water supplies once it becomes operational in 2023.
There is still a lot of research that needs to be done on finding the best complement of technologies that would ensure that the wastewater is safe for the environment and the people.
“At this time, the processes we examined are expensive for treatment plants,” said Aga, “but scientists and engineers are constantly doing research to make things better and more cost effective. I wouldn’t be surprised if in the near future a less expensive, more innovative way to reduce the presence of pharmaceuticals and other micropollutants in wastewater is implemented.”
Aga is part of a collective group that is looking into streamlining the wastewater treatment process. They investigated methods that would reduce the amounts of pharmaceuticals in wastewater such as using urine-diverting toilets at homes and offices. They are hopeful that it could reduce its concentration before it heads into wastewater treatment plants, while also sequestering nitrogen and phosphorus for fertilizer use.
It would just be a matter of time before the right technology and methodology be adopted before the dream of restoring wastewater into a potable state could be achieved on a much larger scale. Aga and her group of researchers are confident that the solution is just around the corner.
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