Clear Lake Sanitary District News and Information Update
From the Administrator/Superintendent, Mitch Hanson
UV Disinfection Project
The District completed a $1.2 million UV disinfection project May 31, 2019 in response to regulatory requirements. The UV system is capable of treating 11.4 million gallons per day. This project helped the Sanitary District meet the Iowa DNR E-Coli compliance schedule.
In response to regulatory requirements for reducing nutrients (total nitrogen and phosphorus) the District hired HDR engineering to prepare and submit to the DNR a Nutrient Reduction Strategy Report in June 2018. The report outlines different methods for reducing nutrients by March 2023. One method and probably the least cost option is to install an in-basin probe and control system intended to enhance the existing treatment system’s controls ability to remove nutrients biologically. The in-basin system was purchased in May 2019 and was placed online fully in late 2022. Nutrient removal will then be monitored for the next couple of years. If needed, the report lists other options that will complement the in-basin probe and control system to further reduce nutrients.
SBR Inner Wall Project
Bids were received March 2019 for the SBR Inner Wall project but were rejected since they were over the engineer’s estimate. This project was rebid in the fall of 2019. Henkel Construction was awarded the construction contract. The scope of this project includes forming and pouring an eight thick inner wall around the of the four SBR treatment tanks. The objective of this project is to add 30 to 40 years of life to the deteriorating concrete walls. This was a 2 year project and was completed in October of 2021.
Pretreatment Upgrade Project
This project was designed to update one of CLSD’s pretreatment screens that remove any large materials that should not be in the waste. The new screen also has 3mm openings on it to collect smaller materials to better protect the rest of the process. Also, the grit system was upgraded to remove the majority of the inorganic waste. This project should be complete by the end of 2022.