Phase 1B WWTP Biological Improvements

In 2014, the District completed an update to its 2008 Facility Plan, identifying the scope for Phase 1B improvements. The treatment facility maintains a capacity of 8.63 MGD but meets current and future regulatory requirements and has a simplified hydraulic profile. The $49 million project was funded through the IEPA Water Pollution Control Loan Program and included the following major additions and improvements:

• Raw Sewage Pumping Station – Within the existing structure, upgraded the existing pumping equipment, electrical equipment, force mains, valves, and other appurtenances to pump the Daily Maximum Flow (DMF) to the new biological process and flow in excess of the DMF to the excess flow facilities.
• Primary Clarifiers – Provided new rectangular or circular primary clarifiers for the full DMF. Provided new primary sludge pumping facilities.
• Biological Process – Provided a new activated sludge process to replace aged RBCs and to meet anticipated lower ammonia limits and a 1.0 mg/L phosphorus limit. Identified improvements to meet a 0.1 and 0.5 mg/L phosphorus limit and potential future total nitrogen limits 8.0 mg/I. Including Digester supernatant, WAS thickening, and dewatering centrate treatment (sidestream treatment) to reduce ammonia load to the activated sludge process.
• Secondary Clarifiers – Provided new circular secondary clarifiers for the full DMF.
• Disinfection – Provided a new UV disinfection system for the full DMF.Provided chlorine disinfection for Excess Flow.
• Excess Flow – Converted three existing primary clarifiers to excess flow clarifiers.
• Operations and Electrical Building – New structure for aeration system, turbo blowers, and RAS/WAS pumps. In addition, new electrical switch gear, transfer switch, and dual fuel (natural gas and biogas) generator.
• Primary Sludge Fermentation Facilities – Produce VFAs for the biological phosphorus removal process. Provided odor control for the fermentation tanks either by covering the tanks or treatment.
• SCADA – A computer-based Supervisory, Control, and Data Acquisition (SCADA) system for monitoring and control of the new facilities. Operational Assistance Dashboard screens assist in biological phosphorus removal.