The water we drinkStudents design innovative wastewater treatment process for removing pharmaceuticals

Four Chemical Engineering students Ryerson University in Toronto, Ontario, have discovered a potential solution to the rising levels of pharmaceuticals ending up in the water supply, particularly worrisome around hospitals and long-term care facilities, where pharmaceutical use is heavy (see “U.S. Water Supply Contaminated by Pharmaceuticals,” 11 March 2008 HSNW; and “Growing Worries about Unregulated Chemicals in Water,” 8 December 2009 HSNW).

The four students have designed an advanced wastewater treatment system which would remove 90 percent of pharmaceuticals and endocrine-disrupting compounds (EDCs) using commercially available technology. Currently no such sewage treatment plant exists in North America.

At a time when tap water is being hailed as the environmentally responsible choice over bottled water, the amount of pharmaceutical medications making their way into the water supply through improper disposal and bodily elimination warrants some concern. As part of their final-year undergraduate project, Kirill Cheiko, Reuben Fernandes, Charles Gilmour, and Pawel Kita used research data from academic and industry sources to design an award-winning simulated wastewater treatment plant to deal with the potentially harmful waste.

“In Canada, the government doesn’t enforce the removal of pharmaceutical drugs and EDCs, including Bisphenol A, from wastewater. As a result, municipalities don’t currently pursue removal, since it would incur extra expense,” said Cheiko. “That said, it could also potentially reduce health-care costs.”

Many prescription and over-the-counter drugs are flushed down the toilet. Others cannot be fully metabolized by the body and are eliminated soon after administration. While the rate of elimination varies (at least five per cent of acetaminophen and up to 80 per cent of the antibiotic ciprofloxacin), the final result is the same: biologically resistant contaminants end up in municipal wastewater.

Eventually, those chemicals enter the environment and the drinking water supply. While there haven’t been any studies done to determine the long-term effects of these pharmaceuticals and EDCs on humans, concerns have nevertheless been raised. Even in trace amounts, for example, chemotherapy drugs can inhibit normal cell function; and pain-relievers and blood-pressure diuretics can lead to liver damage. Regarding reproduction and development, pharmaceuticals and EDCs have also been implicated in such conditions as polycystic ovarian syndrome and hypospadias (a birth defect involving the male urethra).

The students’ proposed innovative design uses two processes in combination, both using commercially available technology. First, wastewater is subjected to membrane biological reactors. This activity increases the amount of bacteria already present in the treatment process and makes them “hungrier.” From there, sewage goes through an advanced oxidization process. Typically used to treat drinking water, this process works in the same way as an antioxidant does in the body: it destroys harmful toxins. But whereas most wastewater treatment plants use chlorine as a disinfectant the students proposed using ultraviolet light (UV) and hydrogen peroxide for the purposes of advanced oxidation and disinfection. Normally, UV light would be unable to penetrate murky wastewater, but after undergoing the membrane biological reactor, liquid waste in the students’ simulated wastewater treatment plants would be clear enough to permit the use of UV light. Afterwards, the students concluded, the wastewater would be clean enough to go straight into lakes and rivers.

The students and faculty advisor Professor Manuel Alvarez Cuenca are seeking funding to test the proposal in Ryerson’s Laboratory of Water Treatment Technologies. They also recommend, however, that municipalities conduct their own research and set up pilot studies around the areas’ hospitals and long-term care facilities.