Trouble Free UV Disinfection of Lagoon Water for Irrigation

7 years without cleaning.



Project Background

Cortland is Illinois’ first wastewater reuse project and was based on treating wastewater by the use of a local lagoon system. UV disinfection is not normally in conjunction with lagoon effluent. The low quality of the water decreases the UV transmittance, and thus compromises the required disinfection. However, through close collaboration with the engineering firm Sheaffer Environmental; a complete treatment process was devised and approved by the State of Illinois.


The Enaqua Solution

A continuous, reliable, regulated supply of UV energy is a critical requirement when UV is applied for disinfection. This is required in order to guarantee continuity of process operations and safe, uncontaminated water for reuse. Uniform UV exposure was therefore essential in Enaqua’s solution offering in order to ensure a continuous premium disinfection quality. Enaqua’s UV design places the lamps outside of the water having the water flowing through fouling resistant AFPTM tubes. The lamps are placed so that they surround the water conveying tubes. Each tube hereby gets exposed to UV from all sides taking full advantage of the radiation provided by the lamps. The volume of water near the UV lamps is hereby maximized.


Advantages and Benefits

The Non-Contact UV unit from Enaqua has now been in operation for more than 10 years. Cortland has done zero maintenance within these years. Not a single ballast has been replaced. The system still provides the right treatment in order to even exceed the regulatory quality limits for water reuse. The solution has essentially eliminated any UV related maintenance in Cortland’s operational costs providing extensive savings.

Water trouble


System design parameters
Peak Decant Flow5,500 GPM (reuse)
Average Daily Flow1.5 MGD
UV Transmittance65%
Disinfection Limit22/100ml Fecal
Enaqua Product BaseC-Series
Upstream TreatmentAerated Lagoon
Year Installed2004