City of Hettinger, Lagoon Cell #3 Repair

Typical of most North Dakota rural communities, the City of Hettinger treats its sanitary effluent via a series of gravity sewer mains and uses a three-cell facultative lagoon system. The current system is comprised of two primary cells and one secondary cell. Primary Cells #1 and #2 were in good working condition, while secondary Cell #3 had begun to experience an exceedingly large amount of seepage through the existing clay liner. The system also started to show its age in other areas, such as the deterioration of the force main pipe from Cell #2, which delivers water up to Cell #3.

Due to several years of dry weather, the City of Hettinger’s secondary sanitary lagoon cell had dried up from evaporation and irrigation, causing the thin sections of the liner to crack. When water was placed into the secondary cell, the cracks did not seal, and water seeped at a high rate down the hill to the primary cell. The water also flowed across the top of the berm, which provided access to the lift station, causing impassible conditions and allowing weeds to grow at an increased rate. Additionally, the seepage had decreased available treated water for irrigation. To control seepage to groundwater and provide favorable environmental conditions for wastewater treatment, the City needed to remove and replace the existing liner immediately.

This project replaced the cracked lining, installed an impermeable high-density, environmentally friendly polyethylene plastic liner, and sealed the entire pond, allowing treated water to be retained and used for irrigation. Primary Cells #1 & #2 are pumped into secondary Cell #3 two or three times a year. Then the city golf course pumps this treated water to a holding pond located at the golf course for irrigation.

In addition to providing water for golf course irrigation, this project reduced maintenance costs and the number of hours needed for the treatment process. Also, the project included the force main piping replacement between Cells #2 and #3 to ensure no breaks will compromise either cell berm.

The City was awarded a $111,500 Community Development Block Grant, a USDA Rural Development $228,000 loan, and a USDA $185,650 grant to complete the project. Brosz Engineering provided funding assistance, surveying, preliminary engineering, and construction engineering services.

Brosz Engineering received the 2021 ND ACEC Engineering Excellence Award in the Waste & Storm Water Category for innovative, sustainable, and cost-effective civil engineering solutions.