The City of St. Martin, MN had been operating its water system with two shallow wells near a creek, which had benzene levels above the maximum contaminant level (MCL). The geology of the area is underlain with a granite shelf, making it difficult to find sites with a sufficient water yield within the city limits. The City drilled two new wells to the east of the city that contained high levels of iron, manganese and ammonia. While not dangerous, the impurities were not pleasing to residents.
The City decided to investigate a biological treatment pilot program, using naturally occurring bacteria instead of chemicals to remove contaminants. Upon achieving successful results from the pilot study, the City authorized us to design and bid the first fully biological filtration water treatment plant in Minnesota.