Sanitary district upgrades lagoons for full cold weather ammonia nitrification within existing footprint.

Project Background & Challenges

Located 120 miles due west of Chicago very near the Iowa/Illinois border is Park View, Iowa. The Park View Water and Sanitary District had been operating a three-cell, 0.5 MGD lagoon facility, but in February 2018 the facility had enlisted the help of the engineers at Strand Associates to help it meet the needs of an impending permit by meeting effluent limits as low as 1.2 mg/L for a monthly average.


The Nexom Solution

Strand Associates reached out to Nexom on behalf of Park View to upgrade the PVSD lagoons with optAER® fine-bubble aeration and lagoon upgrades, as well as SAGR® post-lagoon nitrification.

Optimizing lagoons for TSS and BOD reduction

Implementing optAER® fine-bubble aeration is an effective way to retain the simplicity and low-O&M nature of a lagoon system, while dramatically increasing its ability to reduce suspended solids, BOD, ammonia, and total nitrogen. By efficiently delivering oxygen in the form of fine-bubble aeration to the lagoon’s biology, the lagoon can remove substantially more loading within the same basin, often dramatically extending the life of this simple-to-operate infrastructure. And with the system’s diffusers suspended from floating laterals (which freeze into any surface ice without issue), the system is easy to maintain from the water surface.


Achieving ammonia limits in frozen lagoons

SAGR® fully-aerated media beds provide ample oxygen and surface area to both polish cBOD5 and fully nitrify ammonia. The rock media retains heat to offset the impact of rapid decline in water temperatures during cold snaps in the fall.

Another key to a SAGR’s success is also its ability to offset the impact of reduced bacterial metabolism and reproduction. Using the patented Step-Feed process, in which it pre-grows additional nitrifying biomass when the water is warm so that, when the water cools even to <1°C / <34°F, there is more than enough nitrifying bacteria available to fully nitrify ammonia to <1 mg/L.

Best of all, a SAGR achieves all these ends with operational complexity over a standard aerated lagoon.

Site Construction

Civil work began on the site in February of 2021, with the SAGR being commissioned ten months later.

Thanks to the improved treatment of the optAER-enhanced lagoons and the ability for the SAGR to polish lagoon effluent, the SAGR was built within the existing footprint of the third lagoon cell and the distinctive four-cell design is in accordance with the 2016 update to the Iowa DNR New Technology Assessment No. 11-1.

Upgraded System Performance

Since the site was commissioned in November 2021, the site has recently wrapped up its first winter of compliance. Given the performance demonstrated at more than 40 Iowa SAGR facilities, the Park View Water and Sanitary District can sleep easy at night, knowing that their lagoon-based wastewater treatment plant is equipped to meet its ammonia limits now and into the future.

Project Information

Project Type: Lagoon-based municipal wastewater treatment

Completion Date: November 2021

Treatment Objectives

Design Flow:

  • 500 MGD (AWW)
  • 492 (ADW)

Effulent Objectives:

  • <4.1 mg/L TAN (Winter)
  • <1.2 mg/L TAN (Summer)
  • <20 mg/L cBOD5
  • <20 mg/L TSS

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