Algae in lakes and reservoirs can create issues for drinking water plants including toxins, bad taste and unpleasant odors in the water. While there are a number of treatment methods used to deal with this problem, ozone treatment of the water has emerged as a proven and cost effective method.
Depending on where and how the ozone is applied to the process, the ozone can serve two purposes: primary disinfection and removal of algae related compounds that pose health or aesthetic risks to the drinking water plants customers.
The city of Oregon in Ohio was concerned about algae related issues from their intake in Lake Erie due to cyanobacteria that can produce microcystin, a toxin. Toledo had experienced a severe issue with this toxin that resulted in a 2014 temporary ban on the use of water from their drinking water plant. This cause Oregon to look for solutions before they experienced a similar problem.
In Oregon’s process, water from lake Erie will be treated with ozone and then go through biological filtration. The approach will remove algae-related toxins. The process works because ozone breaks down the toxins into molecules that are quickly digested by the biology living in the filter.
The process was first tested at the pilot scale for several months to prove that it worked well. The full scale system is expected to be in operation by the algae season of 2017. Other advantages include reduced use of chlorine, improved disinfection and reduced disinfection byproducts. Ozone also eliminates trace organic compounds.
The project is expected to cost $14 million, with funds mainly coming from the Ohio Environmental Protection Agency’s Water Supply Resolving Loan Account. Oregon’s water rates will increase about $2 to $3 more a month for the improved quality and safety.