MASTER PLANNING AND WTP SYSTEM IMPROVEMENTS
St. Cloud, MinnesotaAbout the Project
Although the St. Cloud Water Treatment Facility (SCWTF) was relatively “new”, numerous existing systems had been identified as problematic from either an operational, maintenance, or performance standpoint.The condition of process equipment was on the decline, regulatory requirements were increasingly strict with critical deadlines rapidly approaching, and consistent community growth was challenging the treatment capacity of the facility.
Project Details
Date: 2008 – Present
Client: City of St. Cloud
Key Project Elements
- Design Constraints within Existing Footprint
- Facility Condition Assessment
- Development of Implementation Plan
- Renovations/Improvements to Existing Facility
Enhancing Performance and Capacity through Rehabilitation and Technology Upgrades
In an effort to first optimize the existing SCWTF, the AE2S team completed a detailed review of the current treatment facility performance and performed an on-site Facility Condition Assessment to identify potential problems and opportunities to optimize the existing process.Technologies were evaluated based on process effectiveness with respect to target treatment goals, constructability and implementation into the existing facility, and estimated total present worth of each alternative.
The SCWTF Master Plan provided a valuable tool for addressing existing deficiencies, optimizing existing systems, and providing clear direction for the City of St. Cloud. Phase I Improvements included the rehabilitation of the first stage train No. 1 clarifier and the existing north filters. The north filters did not meet current turbidity effluent standards.
The rehabilitation improvements allowed the SCWTF to meet individual turbidity standards, improve control, and increase overall filtration capacity from 16.9 MGD to 25 MGD. The Phase II SCWTF Generator and Rehabilitation Project is currently under construction.
The project primarily consists of a standby generator and structural enclosure, rehabilitation of the “south” filters, miscellaneous chemical feed system improvements, and Instrumentation and Controls (I&C) improvements to the facility’s Supervisory Control and Data Acquisition (SCADA) system.
Strengthening Treatment Efficiency and Addressing Water Quality Concerns
AE2S completed the design and construction of the Flow Train III Equipment Installation Project, which installed flocculation equipment, inclined plate settlers, lime softening solids contact clarifier, and a fully redundant batch lime slaking system.To further complicate an already complex Project, all equipment had to be brought into the WTF through an 8-foot x 8-foot removable wall panel. Concurrent with the Flow Train III Equipment Installation Project, AE2S conducted a year-long Advanced Treatment Process and Evaluation Pilot Study.
The pilot study evaluated several advanced treatment technologies that would best address areas of concern for the SCWTF such as Taste & Odor (T&O), Disinfectant & Disinfection By-Products (D/DBPs), and Contaminants of Emerging Concern (CECs).
The result of this pilot study and associated 20-year lifecycle cost analysis identified ozonation, biological filtration, and UV Light disinfection as the best process technologies to most effectively and efficiently meet the needs of the SCWTF.
AE2S recently completed the design of the SCWTF Advanced Process Improvements and Upgrades, as well as successfully bid the Project. Construction commenced in September 2020 to install the advanced process technologies identified by the pilot study, implement strategic upgrades, and expand the administrative areas.