News Release 

Treating wastewater with ozone could convert pharmaceuticals into toxic compounds

American Chemical Society

With water scarcity intensifying, wastewater treatment and reuse are gaining popularity. But some methods for killing microbes in wastewater create disinfection byproducts (DBPs) that could be harmful to human health. Now researchers have found that ozone treatment and subsequent chlorination can convert trace amounts of some pharmaceuticals in wastewater into DBPs called halonitromethanes. They report their results in Environmental Science & Technology.

The combination of ozone and chlorine kills most bacteria and viruses in wastewater. Compared with chlorine treatment alone, ozone also reduces the formation of many DBPs. Recently, however, scientists have discovered that ozone can increase the formation of potentially toxic halonitromethanes, such as chloropicrin, in chlorine-treated wastewater. Jiaming Lily Shi and Daniel McCurry wanted to determine which molecules in the wastewater were being converted to chloropricin and how.

To find out, the researchers collected wastewater samples from three treatment plants in Southern California. The team discovered that ozone treatment produced nitromethane, which could have been formed from some nitrogen-containing drugs in the wastewater, including stimulants such as ephedrine and methamphetamine and certain antidepressants. Then, chlorination transformed the nitromethane into chloropricin. The pharmaceuticals, which enter wastewater through sewage, are not removed completely by conventional wastewater treatment. Future work should address how effectively processes that occur after ozone treatment can remove the nitromethane intermediate, the researchers say.

###

The authors acknowledge funding from the Foundation for Cross Connection Control and Hydraulic Research.

The paper's abstract will be available on February 5 at 8 a.m. Eastern time here: http://pubs.acs.org/doi/abs/10.1021/acs.est.9b04742

For more research news, journalists and public information officers are encouraged to apply for complimentary press registration for the ACS Spring 2020 National Meeting & Exposition in Philadelphia.

The American Chemical Society (ACS) is a nonprofit organization chartered by the U.S. Congress. ACS' mission is to advance the broader chemistry enterprise and its practitioners for the benefit of Earth and its people. The Society is a global leader in providing access to chemistry-related information and research through its multiple research solutions, peer-reviewed journals, scientific conferences, eBooks and weekly news periodical Chemical & Engineering News. ACS journals are among the most cited, most trusted and most read within the scientific literature; however, ACS itself does not conduct chemical research. As a specialist in scientific information solutions (including SciFinder® and STN®), its CAS division powers global research, discovery and innovation. ACS' main offices are in Washington, D.C., and Columbus, Ohio.

To automatically receive news releases from the American Chemical Society, contact newsroom@acs.org.

Follow us: Twitter | Facebook

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.