Low-cost, low-tech solution to improve water quality and remove carcinogens
Michigan Technological University (MT) researchers have developed low-tech, low-cost solutions to improve water quality.
Mohammad Alizadeh Fard, doctoral student at MT, and Brian Barkdoll, professor of civil and environmental engineering, have created a way to remove micropollutants using renewable materials.
Many communities throughout the US use large water-storage tanks for municipal drinking use. Often, these tanks have a line in to supply water, and a line out. However, these lines are frequently at the tank bottom.
The tanks are refilled daily, yet the water at the top of the tank is never used and becomes stagnant. According to an MT statement, despite municipal water supplies being treated with chlorine, the top water layer can become stagnant and a breeding ground for bacteria, algae or waterborne sicknesses such as giardia and E. coli.
"If the water is not moving, (bacteria and algae) can start growing," Barkdoll says in an MT statement.
"It may not be originally from the water source; it could be from the air. Or the chlorine in the stagnant water could be used up after some time. You want the water to keep moving, especially in hot regions of the country."
If the water tank is ‘drawn down’ significantly, perhaps in response to a fire in the community, people will end up drinking the stagnant water.
“After a fire, people get sick, that's a known thing. That's the problem that we're trying to fix," Barkdoll explains.
Solution
Barkdoll and Alizadeh Fard’s answer to this problem is shower head-like attachments that can be added to new or existing water tanks for minimal cost. According to the scientists, adding a PVC-pipe sprinkler at the top of the tank and a reverse sprinkler at the bottom injects water into the system and keeps all the water circulating.
An article on their innovation has been published in the most recent edition of the Journal of Hydraulic Engineering.
Taking carcinogens out of the water supply
Micropollutants such as pharmaceuticals, hormones, microplastics, antifungal compounds and types of industrial waste present a different challenge.
Despite being present in only microscopic amounts, these pollutants can have a carcinogenic effect on humans. Retrofitting plants to filter these contaminants is expensive.
“These contaminants have long-term effects on health," Alizadeh Fard says. "Most of our treatment plants have not been designed to remove them from water, so it's important to find a reliable solution to address the problem.”
The scientists used polymer-coated magnetic nanoparticles to adsorb Tonalide (used to mask odours and often found in detergents), Bisphenol-A (better known as BPA, used to make plastics clear and tough), Triclosan (an anti-bacterial and anti-fungal agent used in cleaning products that is now banned), Metolachlor (a herbicide), Ketoprofen (an anti-inflammatory) and Estriol (an estrogen supplement).
The polymer-coated magnetic nanoparticles were most effective at adsorbing Ketoprofen and BPA, removing the pollutants in 15 minutes with 98% and 95% effectiveness, respectively, with only 0.1 milligram of the adsorbent.
Because the nanoparticles are magnetic, the researchers can safely remove them from the water once their work is done, using magnets. What’s more, the adsorbents can be rinsed with a restorative methanol solution and then be reused.
Scaling up
According to the statement, the two scientists are now looking to scale up their research for use in water treatment plants. The end goal is to develop technologies that can remove micropollutants without requiring costly retrofits.
For Alizadeh Fard, finding effective ways to improve water quality is vital.
“Civil and environmental engineers will have to handle whatever society hands to us," Alizadeh Fard says. "We will have to remove nanoparticles, and other things such as opioids. It's a topic we have to discuss politically and socially as well."
