St. Mary Wastewater Engineering Report: Clean Water Engineering Report Grant

The City of St. Mary is a small community of approximately 300 residents situated along the historical riverbed of the Mississippi river.  The existing wastewater treatment and collection systems were constructed in 1978 and have received minimal repairs and upgrades since that time. The original design included individual grinder pump stations for each sewer customer. Many of these pump stations still consist of the original components installed in 1978. Many components of the both the existing collection and wastewater treatment systems have far outlived their intended design lives. As a result, the city has persistently struggled to maintain the functionality of their collection and treatment systems. The natural degradation of components over the years since 1978 have now added up to the point where the cost of repairs is extensive and outside the normal means of the city.

Heartland Engineering was retained by the city to conduct preliminary investigation and design of the city’s wastewater facilities as part of a Clean Water Engineering Report Grant (CWERG) through the Missouri Department of Natural Resources. The engineering report is ongoing and will outline the cost of options to repair and modernize the collection system. Due to the high cost to construct and maintain pump stations, alternatives such as a traditional gravity collection system will be explored. Options are also being analyzed to create a functional and reliable wastewater treatment system for the city. The expected cost to repair and upgrade the existing treatment facility equipment will be compared versus the cost to construct a non-discharge land application system and other options. Alternatives will be compared not only on a basis of up-front construction costs, but also in regards to long-term operations and maintenance, major equipment replacement, and the depreciation value of assets on-hand.

Finally, the completed report will be used as part of a funding application package, most likely through the Missouri DNR State Revolving Fund, to help the city acquire the funding necessary to complete final design and construction of the proposed project. The report is anticipated to be complete by mid-2025.