MDWASD NORTH DISTRICT WASTEWATER TREATMENT PLANT (NDWWTP) RENEWAL AND REPLACEMENT IMPROVEMENT PROGRAM
Miami-Dade Water and Sewer Department (MDWASD), beginning in 2007, initiated a plant-wide renewal and replacement program to evaluate, rehabilitate, and upgrade facilities at the NDWWTP under project E06-MDWASD-13. The NDWWTP is one of three regional MDWASD treatment facilities that receive and treat wastewater from Miami-Dade County, and has a dry-weather permitted capacity of 112.5 MGD, and average flow of about 80 MGD. The plant operates with six primary and 12 secondary clarifiers, and pumps raw primary and waste activated sludge to the MDWASD Central District WWTP for processing.
The R&R initial assessment identified a number of necessary and critical improvements focused on rehabilitation of existing equipment, processes, and facilities at the NDWWTP. Following the facility assessment and development of recommendations for improvements, MDWASD accepted the proposed priority list. MDWASD is continuing the implementation of the recommended projects as part of the Consent Decree (CD) negotiated with the USEPA in 2013, compliance with Ocean Outfall Legislation (OOL), projected impacts associated with Sea Level Rise and Storm Surge predictions.
CES Consultants, Inc., as part of the engineering team tasked with the R&R improvements, is providing professional civil, structural, and cost estimating engineering services for the development of studies and design of critical facility improvements. The various R&R projects for the NDWWTP include the following.
- Design of improvements to the Grit Removal Process facilities to bring the operation back on-line and improve operator safety.
- Facility evaluation and basis of design for structure and equipment replacement of a significant portion of the primary electrical infrastructure identified as a Critical Phase Project requiring immediate attention for operator safety, and imminent operational plant failure.
- Evaluation and basis of design for improvements to the primary clarifiers that are in critical need of repair and rehabilitation. Primary Clarifiers 1-6 constructed in 1978/1989/1996 have highly corroded internal mechanisms and domes that have surpassed their reliable and functional life.
- Evaluation and basis of design for secondary clarifiers 1 through 12 that have significant structural and equipment corrosion, and are well beyond their useful life. The clarifier component improvements include replacement of the collector mechanisms with scraper blade type mechanisms, enlargement of the center wells, structural rehabilitation for the effluent launders, rehabilitation and recoating of corroded and eroded concrete, and replacement of steel clarifier access walkways.
- Design for structural components for new pump nos. 5 and 6 in the existing Deep Injection Well Pump Station. Existing pump nos. 1 through 4, installed in 1994, have a rated capacity of 16,000 GPM with 900 HP motors. The project also includes structural evaluation of the station for new equipment loads and wetwell reconfiguration.
- Design and QA/QC of approximately 4,200 feet of 48-inch DI force main in NW 54th Street, including micro-tunneling, for improvement of hydraulic capacity within the NDWWTP service area.
- Basis of design for improvements to Pump Station 301, located in the NDWWTP service area, including structural evaluation of the existing building, and development of structural elements for a new station option.