Removal of Pharmaceuticals Using an Eco-cleaner – Constructed Wetland Wastewater Treatment Plant
Master's degree students created a small wetland at the AZ Groeninge University Hospital in Kortrijk and utilized natural filtration processes to treat water from the building.
Medications that people take, such as anti-inflammatory drugs or antibiotics, are not always fully absorbed by the body, and their residues end up in wastewater.
Existing wastewater treatment plants are unable to remove all of these residues, and they can then cause harm to the plants and animals living in the water.
Professor Diederik Rousseau, who supervised the students' master's theses, said that the contamination does not affect drinking water, which undergoes a more rigorous purification process.
While constructed wetlands have long been considered an effective method for wastewater treatment (though not so much in the Slovak Republic yet), students Laurens Huba and Lige Vanseveren wanted to find out more about how bacteria and plants cope with pharmaceutical residues, as there is not much information available about it.
They found that although the constructed wetland did not completely remove all drug residues, the use of ozone in a second step made it possible to complete the purification process.
Rousseau says about this:
"What we really discovered is that these technologies complement each other. Some pharmaceuticals are removed in the reed bed, but not by ozonation, and vice versa. So this combination gives us a greater guarantee of well-treated water.
'Constructed wetlands, unlike conventional wastewater treatment plants, blend into their environment and are simpler and cheaper to operate,' he adds.
The team worked with an innovative type of constructed wetland from the company Rietland, which is actively aerated. This greatly increases efficiency, meaning that such a constructed wetland requires much less space than other types of reed bed WWTPs. (by the end of this year at the latest, we will present a similar type of Eco-cleaners in our portfolio as well)
The five-month experiment required filling a portable container with gravel and planting wetland plants. It also included a settling tank to capture coarse impurities. The first laboratory test of the wastewater showed the presence of residues of beta-blockers, anti-inflammatory drugs, anticonvulsants, narcotics, antacids, and antibiotics. After passing through the constructed wetland, most of these elements were removed, but some non-biodegradable substances remained, such as the widely used anti-inflammatory drug diclofenac.
The solution proposed by Professor Stijn Van Hulle was to subsequently treat the water using ozone, which can be produced on-site. But given the high energy consumption requirements for ozone production, the team still needs to find a way to better control its dosing."
A study by Van Hulle's former student, Aegina Malaj, states that organic chemicals (which include both pharmaceutical residues and pesticides, dyes, and other substances) THREATEN the ecological integrity and biodiversity of nearly half of Europe's water bodies.
Rousseau says:
Exposure to low concentrations of chemicals does not kill plants or animals directly, but it can have a cumulative effect on their bodies, for example by disrupting hormonal balance.
He also added that while there are currently no European standards for removing pharmaceutical residues from wastewater, Switzerland has recently introduced such new legislation, and European lawmakers are also looking into this issue.
Do you think conventional biological wastewater treatment plants will be able to handle this?
Original article by Paula Dear