Solids Handling Improvement Project (SHIP)

Goleta Sanitary District (GSD) owns and operates the Goleta Water Resource Recovery Facility (WRRF) located at One William Moffett Place, near the Santa Barbara Municipal Airport (SBA), in an unincorporated coastal area of Santa Barbara County, California. GSD is a special services district that provides wastewater collection, treatment, and disposal services to residents and businesses within the Goleta Valley. The GSD WRRF has an annual average design flow capacity to treat 7.64 million gallons per day (MGD) of wastewater, but it is currently treating an annual average flow of approximately 4.9 MGD. The treatment process at WRRF begins with bar screens to remove large debris, as well as aerated grit tanks and two cyclone separators to remove grit and sand. The wastewater then flows into three primary clarifiers for solids removal prior to secondary treatment. The secondary treatment at WRRF includes biofilters, three aeration basins, and four secondary clarifiers. Currently, GSD's WRRF has the following solids and gas handling process for treatment of solids recovered from wastewater. Primary Sludge (PS) coming from primary clarifiers is pumped to the digestion process. Waste activated sludge (WAS) generated from secondary treatment is thickened to 6% solids using two screw thickeners; the resulting thickened WAS (TWAS) is pumped to the digestion process. Combined PS and TWAS solids are stabilized in three mesophilic anaerobic digesters (MADs ), operated in parallel. Digested biosolids are dewatered by two screw presses and then loaded onto trucks for transport off-site. A small portion of the dewatered biosolids is diverted into sludge drying beds for further stabilization to become a Class A product. Biogas produced in the digesters is burned in boilers to provide hot water for heating the digesters and to supply other heating needs at the WRRF. Biogas that is not required for heating is flared through the waste gas burner. A condition assessment conducted in 2016 indicated that some of the unit processes at WRRF are nearing the end of their service life and would need rehabilitation and replacement soon. A Biosolids and Energy Strategic Plan (BESP) was developed in August 2019 by Hazen and Sawyer (Hazen), which evaluated biosolids unit processes in detail and recommended upgrading existing facilities to mitigate regulatory uncertainties affecting biosolids disposition, to diversify beneficial use outlets, and to approach energy neutrality for the facility. The BESP summarized the capacity evaluation for the existing solids processes, including digesters considering the current and anticipated future flows and loads, and identified the need to build a new digester to maintain firm capacity. Firm capacity was defined as the ability to maintain full treatment capacity with the largest single process unit out of service. The BESP also included assessment of the High Strength Waste (HSW) co-digestion and the feasibility and benefits of reaching energy neutrality. BESP provided GSD with a suite of improvement options for the WRRF, each with its own independent utility and purpose. Goleta Sanitary District is proposing to implement a Solids Handling Improvement Project (SHIP) at its Water Resource Recovery Facility (Project), which includes the construction of a thermal dryer facility. The addition of the thermal dryer facility will decrease the amount of hauled sludge, as well as increase the quality of biosolids produced, thus increasing the potential for beneficial reuse of the product. The proposed Project includes the following components: (1) a thermal dryer, which will heat dewatered sludge to transform it into Class A biosolids; (2) a thermal heater system, which will use natural gas to provide heat to operate the thermal dryer, with the option to convert using biogas produced by the digesters in the future, when gas production increases; (3) loadout facilities, intended to load Class A biosolids into trucks for removal from the site; (4) associated civil, structural, electrical and instrumentation work; and (5) a fire pump for fire suppression system at the new buildings.