Like many other small communities in Iowa, Lenox is expecting much more stringent limits on the effluent of their wastewater lagoons. Currently the community is able to achieve excellent treatment with their lagoons and follow on sand filters during the summer. In the winter however, they struggle with Ammonia. After completing the pilot testing in Gresham, WI; WCS transported the pilot unit down to Lenox in order to provide the city, engineers and state regulators with a chance to see the pilot unit in operation in a local community.
Solution & Results
While the pilot unit was delivered in August of 2011, the influent to the pilot unit from the lagoon had almost no ammonia coming in until the end of November. To keep the biology alive, we were forced to spike the pilot unit with Ammonium Bicarbonate which is the reason for the effluent spikes in the effluent through the 17th of November. Once the lagoon water temperatures got close to 5 oC the ammonia levels in the influent started to climb and we’ve started to see the biology take off and remove the ammonia. The pilot started with a 7 day HRT and was reduced 3 times to an ultimate 1 day over the course of the study. In each instance a reduced HRT was followed by a rise in effluent ammonia and then a decrease following as the biology adapted to the increase loading. Additionally, WCS was asked to run stress tests on the pilot to simulate a power outage. A 48 hour power outage shown by the first gray box showed no ill effects on the performance of the pilot. A 7 day power outage (second gray box) caused a spike in effluent ammonia, but after turning the air on, the biology was fully functional within 24 hours.
Lenox, is pioneering the Bio-Domes in Iowa and has submitted a preliminary design to the Iowa DNR for approval for 2014 construction.