The Village of Andalusia, Illinois utilizes a lagoon system for wastewater treatment. After nearly 30 years of constant use, solids had accumulated on the bottom of the lagoon, gradually reducing its depth and available volume for treatment. Compounding the issue, the lagoon’s aeration equipment was approaching the end of its useful life. This combination presented challenge in meeting BOD, TSS, and ammonia permit levels.
The Village of Andalusia selected Shive-Hattery to optimize its lagoon system. The Shive-Hattery team worked closely with the Illinois Environmental Protection Agency (IL-EPA) to gain clearance for subsurface sludge injection in the neighboring fields.
Shive-Hattery developed a plan for cleaning the lagoon as well as bid-ready documents for securing a contractor for removal and disposal of the solids. While the lagoon was dewatered for sludge removal, Shive-Hattery recommended that imperfections in the impermeable clay lining be repaired to ensure isolation of the lagoon water and prevent possible infiltration.
Shive-Hattery also replaced the old aeration equipment with new fine-bubble diffusers. This equipment uses less power to provide oxygen to the treatment process. The fine-bubble diffusers are between 40% and 60% more efficient than the older technology used for lagoon aeration.
Removing the sludge from the bottom of the lagoon and replacing outdated aeration equipment gave the Village of Andalusia’s wastewater treatment system a spike in standard oxygen transfer efficiency (SOTE), improving treatment performance. This upgrade has also provided a noticeable reduction in operations and maintenance costs.
The lagoon upgrades also placed the Village of Andalusia in good position with IL-EPA, and extended the useful life of the lagoons in treating wastewater.