450 

 

 

Utilization of energy conserving operational methods (e.g., optimization of primary 
sedimentation to reduce utilization of pure oxygen) 

Formal Energy Efficiency Management Program led by a dedicated project engineer. Life cycle cost 
analyses, including cost of energy, are performed during each project design period.  

Maintenance shop and outside lighting at the Joint Water Pollution Control Plant (JWPCP) are replaced 
with LED lighting as existing lights fail. This greatly reduces lighting power consumption and increases 
bulb life.  

The Sanitation Districts have 48 natural gas and 6 electric vehicles in the fleet and is continuing to 
expand our alternative fuel fleet vehicles.  

Approximately 415 employees participate in a rideshare program that provides incentives to encourage 
carpooling, riding bikes and driving alternative fuel vehicles.   

Staff optimizes treatment plant operations to increase energy efficiency.  For example at the treatment 
plants, low-efficiency recessed impeller-style sludge pumps were replaced with higher efficiency screw-
centrifugal type pumps, biological reactors are taken out of service during low flows to reduce power 
consumption of mixers, inlet works influent sewer levels and sedimentation tank effluent channel levels 
are maintained as high as possible to maximize the suction head, and biotrickling scrubbers for primary 
sedimentation tanks are run on low speeds to minimize energy consumption while still containing odors.  

Performance Measures & Results   

-

 

Cumulative system load reduction:  4.8 MW since program initiation in 2006  

-

 

Annual Energy Efficiency Management Program Savings:  $5.7 million during FY 2014-2015  

-

 

Cumulative Energy Efficiency Management Program Savings:  $34 million since program 
initiation in 2006  

 

ENERGY GENERATION & RECOVERY 

 

Indication of management commitment (e.g., standard operating procedures; board/executive 
management renewable energy conversion policy, including quantitative goals developed and 
shared with stakeholders)   

 

Internal energy sources evaluated (e.g., biogas, hydropower, heat in wastewater), and/or 
renewable energy sources evaluated on an ongoing basis (e.g., solar, wind, co-digestion)  

 

Recovery of digester gas in a combined heat and power (CHP) system, and boilers in place (for 
process and building heating)   

 

Conversion of digester biogas to electricity and heat, and/or transportation fuel Yes   

 

Solar panels, wind turbines, heat recovery, in conduit hydro, and/or hydroelectric power 
generation systems installed  

The Joint Water Pollution Control Plant operates a digester gas-fueled, gas turbine-based combined 
cycle power plant that provides 100% of the plant’s electrical energy and process heating requirements 
under normal conditions. Natural gas is used to supplement digester gas to achieve necessary turbine 
generator output levels. Generator outputs are maintained to ensure that no power is imported from 
the electrical utility, while minimizing the amount of natural gas which must be consumed.