Quest Ventures

Biosolids Thickening Facility (GBT)

As part of an ongoing Job Order Contract with the Pima County Wastewater Management Department (PCWWMD), Quest constructed a new Gravity Belt Thickener (GBT) Facility at the Roger Road Wastewater Treatment Plant (RRWWTP). The completed GBT Facility improved critical digester detention times by a factor of 35% and reduced sludge volumes pumped to PCWWMD’s Ina Road Wastewater Pollution Control Facility by 30%.

During the preconstruction phase, Quest met with the Project Team consisting of PCWWMD, onsite RRWTP personnel and the Engineering Team at Brown & Caldwell in order to identify project goals, address the fast track schedule and explore value engineering options which would improve the design and value of the GBT Facility. Specific value engineering alternates were implemented, resulting in cost savings in excess of $35,000, which included piping configuration modifications, concrete construction joint layout revisions, using alternative materials for the GBT sludge hopper and locating a source of service water more convenient to the GBT Facility.

After a Guaranteed Maximum Price (GMP) had been successfully negotiated, Quest began construction of the GBT Facility in January 2007. Construction features included site work, underground and mechanical piping, concrete foundations and structures, structural steel GBT platform and hopper, GBT equipment and system installation, wash and sludge pump system, electrical work, instrumentation systems, painting and odor control features.

The project was completed approximately two weeks ahead of the original May 15th completion goal through the relentless focus on delivery of the GBT equipment that was pre-purchased by PCWWMD, coordination of suppliers and subcontractors and extensive system startup and testing. In addition to completing the project ahead of schedule, the final project cost of $971,000 was approximately 3% under the original GMP.