Electrical Design for HVAC in Biosolids Project at Southeast Treatment Plant - San Francisco, CA

Category: Industrial 

Services Provided: Electrical Engineering 

Completion Date: 2025 

Owner: San Francisco Public Utilities 

Contractor: Bullard’s Heating and Air Inc. 

Project Description

The Southeast Treatment Plant is San Francisco’s largest wastewater treatment facility, responsible for treating approximately 80% of the city’s combined stormwater and wastewater. As part of a long-term modernization effort, the Biosolids Digester Facilities Project (BDFP) is a flagship initiative aimed at replacing and relocating the plant’s outdated solids treatment infrastructure. 

Bullard’s Heating and Air was selected to provide HVAC installation services for part of the BDFP. To support this effort, Pragmatic Professional Engineers (Pragmatic PE) was retained to review the electrical documentation and produce detailed interconnect drawings for all HVAC equipment associated with the project. 

Scope of Work 

Documentation Review 

• Reviewed electrical contract documents prepared by the Engineer of Record. 

• Coordinated closely with the contractor to gather all missing and relevant details. 

• Verified the engineering content of the drawings and added clarification notes for installation. 

• Reviewed motor control diagrams, terminal junction box layouts, and field panel submittals to confirm correct wire terminations. Flagged and corrected any mislabeled terminations. 

Interconnect Drawings 

• Created detailed terminal connection drawings for all HVAC equipment. 

• Evaluated wire sizes, identifying conductors that were undersized for their respective loads and breakers. 

• Added safety and design notes where the original documents lacked adequate provisions. 

Coordination & Execution 

• Maintained active coordination with the HVAC contractor to ensure accurate, field-ready documentation. 

• Facilitated a smoother installation process by anticipating and addressing potential issues early in the design process. 

Results & Impact 

Pragmatic PE’s work resulted in highly accurate and safety-conscious interconnect documentation that aligned with California electrical codes and supported field installation. The enhanced clarity and attention to design ensured seamless execution, reduced field errors, and contributed to the overall success of one of San Francisco’s most critical infrastructure modernization efforts.