Crosslake Wastewater Treatment Facility Improvements
The City of Crosslake is considering a project to improve deficiencies at the Crosslake Wastewater Treatment Facility. The proposed improvements being considered include the following:
- Upgrades to Plant Controls which will allow for better automated controls, improved wastewater treatment, increased plant capacity, and reduced operations staff time.
- Various improvements that will buffer peak flows during high use periods and maintain flows during low flow periods (flow equalization) which will enhance treatment performance and increase Facility treatment capacity.
- Backup emergency power upgrade to provide for treatment operations during natural disaster and other power loss events.
- Modifications to existing pipe and process systems that currently restrict Facility capacity, operations and performance.
- Consideration of a future well supply/storage system for strategic fire protection purposes.
The proposed improvements are estimated to cost around $1.6 million and would be constructed during the summer and fall of 2017.
The Crosslake Wastewater Treatment Facility was originally constructed in 2004. The Facility was constructed with a limited budget and has served the City well, consistently meeting all discharge limits. The Facility currently requires significantly more manual control and operation than other typical facilities and is relatively unique in that it receives highly variable flows that tend to peak on weekends when the Facility has the least amount of staffing. As a result, the City has found that the Facility has now become challenging and expensive to operate and due to variable high flows has reached its maximum treatment capacity.
The Crosslake Wastewater Treatment Facility is a critical part of protecting the water quality of the lakes, streams, and wetlands in and around the City. The Facility treats for phosphorus which is one of the primary contributors to excess algae growth in lakes and streams. Due to the soil conditions and limited farming in the area, point sources such as wastewater plants or onsite drainfields are some of the biggest phosphorus sources to lakes in this region. The City is committed to treating its wastewater to a high level, thus significantly reducing any impact on the environment.
December 2017 Construction Update
During December, the Contractor continued progress on the two tanks. Concrete was poured at the beginning of the December for the walls of both structures, as well as for the top slab (cover) of the equalization basin. Installation of process piping was started and various plant upgrades were made which will continue throughout the winter. These process piping changes are necessary to begin to incorporate the new equalization basin into the existing treatment process and to improve the operational ability of the WWTP to meet peak flows experienced during high use periods in the City. The equalization basin is planned to be fully functional by St. Patrick’s Day (mid-March 2018) in anticipation of peak flows experienced with City festivities. The entire project is planned to be completed by Fall 2018.
November 2017 Construction Update
During November, the Contractor focused on concrete work associated with the equalization basin and the water storage tank. The main slabs and sump areas for both tanks were poured. The contractor used a concrete pump truck to effectively place the concrete on the tied rebar within the forms. A heat tent was erected by the Contractor to protect the concrete from the cold weather so the concrete would be allowed to properly cure and gain strength. Concrete forms and tied rebar for the water tank walls were placed by the end of November with a planned concrete pour for early December.
October 2017 Construction Update
On September 15, 2017, the City of Crosslake awarded the 2017 Wastewater Treatment Plant (WWTP) Improvement Project to Eagle Construction Company Inc. from Little Falls, Minnesota for the amount of $2,227,000.00. Starting in October 2017, the contractor began to mobilize equipment and materials onsite to prepare for the construction of the WWTP improvements. Excavation for the new water storage tank, and also the new equalization basin, was completed. Dewatering equipment was used to lower the ground water table so that the contractor could begin construction activities. With the groundwater elevation lowered below the tank excavation, concrete form were placed and rebar tied in preparation for pouring the concrete base slabs at each tank.