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a14OSimilar Project Experience 6-2 <br />San Diego, California <br />Metcalf & Eddy is providing comprehensive services for the development of centralized <br />processing facilities for sludge from wastewater treatment plants in and around San Diego, <br />California, to replace existing sludge management facilities on Fiesta Island. As part of the <br />program, M&E conducted a sludge management study, developed a master plan, and provided <br />environmental documentation, design, and construction services for a variety of facilities. The <br />program includes a new sludge processing facility, a high-pressure sludge transfer pumping <br />station, sludge and centrate force mains, and a tunnel section of force main. <br />Centralized Sludge Processing Facility <br />M&E designed the Miramar biosolids complex, a 200-dry-tpd centralized sludge processing <br />facility that includes sludge receiving tanks, raw sludge straining and degritting, centrifuge <br />thickening, and anaerobic digestion to process sludge from two new wastewater reclamation <br />plants. <br />The centralized sludge processing facility will also receive digested sludge from the city's <br />primary treatment plant. Combined digested sludge from the primary treatment plant and from <br />on-site digestion will be further processed with centrifuge dewatering, lime stabilization and <br />pasteurization, and storage and load out of the dewatered sludge. <br />The facility includes state-of-the-art processes and equipment such as high-solids centrifuges, <br />vortex-type grit removal from sludge, sludge straining, and pumped mixed anaerobic digesters. <br />Comprehensive pilot testing was performed on the high-solids centrifuge and sludge screens. <br />The project planning provided for cogeneration and privatized facilities for additional sludge <br />processing capacity, including sludge drying, which was carried through preliminary design. <br />The design of the central facilities emphasized aesthetics, odor control, and reduced labor <br />operations. In addition to design, M&E provided site master planning, support for an <br />environmental impact statement and report, permitting, air emissions modeling, an operations <br />and maintenance manual, and start-up services. <br />The process control equipment designed for Miramar consists of 41 DPUs, 10 work stations (five <br />of which are environmentally hardened), 3 fiber-optic data highways connecting all the control <br />equipment, and an interface to a district-wide fiber-optic information network that connects a11 <br />the control systems together. The combined system consists of more than 16,000 input-output <br />points. <br />High-Pressure Sludge Transfer System <br />A high-pressure sludge pumping and force main system is being designed to transfer digested <br />sludge 18 miles from San Diego's advanced primary wastewater treatment plant to the <br />centralized sludge processing facility. The Point Loma sludge pumping station will have a firm <br />pumping capacity of 1,500 gallons per minute, and the design maximum working pressure of the <br />system is 570 psi. The main sludge pumps will be positive displacement, hydraulic diaphragm <br />