One of the growing concerns with water pollution is the increasing presence of pharmaceuticals in wastewater. If not properly filtered, pharmaceuticals can end up in water sources and can have negative consequences to human health, the environment and ecosystems. Thus many researchers and scientists are in a race to find a new method of removing pharmaceuticals in wastewater.
A notable example of pharmaceutical contamination in water systems is ethinylestradiol, which is found in contraceptive pills. This has become major issue in Europe and the United States, where it is reported that the concentrations of estrogen hormones have reached a level of up to 0.83 micrograms per liter. These hormones are also known as endocrine disruptors and they can alter the gender of fish and turn male fish into females.
The European Union has declared that these pharmaceuticals in the water is a serious concern because wastewater treatment plants do not have the means of capturing the substances in an effective manner. Wastewater treatment plants often remove pharmaceuticals through the use of activated sludge tanks, but a significant amount of the compounds inevitably escape the tanks and end up in bodies of water. The region has been seeking a new method of removing pharmaceuticals in wastewater.
A group from VTT and Aalto University is seeking to address this problem by devising a wood-based cellulose fiber yarn that is capable of capturing substances like ethinylestradiol and prevent it from contaminating the water.
They managed to achieve this by attaching a cyclic sugar onto the surface of the cellulose fiber yarn. These sugars bond chemically to the surface of the yarn and form pockets where hydrophobic pharmaceutical substances are captured. This method takes only a few minutes for the pharmaceutical compounds to become bound to the cyclic sugars which are attached to the surfaces and cavities of the fiber. The team demonstrated that one gram of fiber yarn can capture approximately 2.5 milligrams of the ethinylestradiol hormone.
“Hormone capture would be most effective in wastewater treatment plants and hospitals, since the wastewater in these facilities contains a higher concentration of the compounds. We are developing a wood-based affordable material that could be thrown into a tank in a wastewater treatment plant or used as a filter in a pipe connected to the tank. After some time, the material is collected mechanically. It is disposed of by incineration, but it is also possible to separate the pharmaceuticals and reuse the material,” says VTT’s Senior Scientist Hannes Orelma.
The wood-pulp-based fiber yarn that was used for the study was created using deep eutectic solvents (DES), utilizing a method developed by VTT. DES typifies the new generation of organic solvents which are designed to be environmentally friendly. The study wanted to make sure that the solvent they chose for addressing the pharmaceutical contamination is itself not a threat to the environment.
“It would be interesting to test how effectively the cellulose yarns can capture hormones and pharmaceuticals from wastewater at a larger scale,” says Orelma.
It is hoped that the new method for removing pharmaceuticals from wastewater would be used as a template for larger scale projects around the world because addressing the issue of contaminants is vital to ensure the quality of treated wastewater before it can be released back into the environment.
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