Donnellson, Iowa Solves Critical Need at Sewage Treatment Plant

Written by Theresa Rose on December 4, 2015

The engineering firm of French-Reneker-Associates, Inc. of Fairfield, Iowa, working with the City of Donnellson has completed a project to upgrade the City’s sewage treatment plant to meet Iowa Department of Natural Resources Standards.

The project reduces the concentration of ammonia nitrogen that is discharged into an adjacent stream by 94% compared to how the lagoon system was previously performing. The project has also essentially eliminated E. coli bacteria entering the stream. Iowa’s streams are plagued with high concentrations of ammonia and bacteria which affects our drinking water, fish that try to live in the streams, and the use of the streams and lakes for recreation. Iowa is attempting to improve water quality through a nutrient reduction strategy. Donnellson is a small contributor of pollutants to the streams relative to all of Iowa, but they have made their contribution to the good for all.

The project included upgrading the aeration system to provide more oxygen to the wastewater for better treatment throughout the year and placing an insulated cover over the lagoon to keep the wastewater warmer during the winter months. The bacteria that provide the treatment in the lagoon are more active and more effective with warmer water.

The project also includes an ultraviolet light system at the end of the treatment train to rid the wastewater of E. coli bacteria. Some sewer treatment plants use chlorine to kill E. coli. Ultraviolet light is a relatively new method for disinfection. Chlorine is a dangerous chemical for the plant operator to handle. Chlorine leaves a residual chemical that is harmful to fish and other wildlife. The ultraviolet system does not leave a residual chemical and is easier and safer to be around than chlorine.

Donnellson has gone a step further by also adding solar panels to reduce their power costs at the lagoon. The solar panels were installed in 2014 and are working very effectively.

Most people do not think to tour a sewage treatment plant. It may not be on your bucket list, but the Donnellson plant is worth a trip if you have any interest in wastewater treatment or in water quality in general.

For a tour of the plant, contact City Hall at 319-835-5714