Total system concepts for municipal and governmental applications – water and wastewater treatment, methane gas recovery and central vacuum cleaning of schools, buses, administrative offices and other local public facilities.

Municipal water and wastewater aeration systems

For your water and wastewater aeration needs, look for systems rather than just blowers. And look for the most efficient package that will deliver air at the lowest net energy cost. You can save tens of thousands of dollars annually with Spencer systems that are process-optimized and technology-ready for the latest Biological Nutrient Removal (BNR) and Membrane Bioreactor (MBR) concepts.


Spencer’s aeration systems include energy-efficient multistage centrifugal blowers, variable frequency drives, dissolved oxygen controls, and in-house designed and built electrical control systems. Spencer has years of experience and hundreds of systems installed worldwide. We will design your entire system and accept responsibility for the integrated operation of all system components that we provide.

Typical Markets/Uses

Location/Activity Spencer product
Grit collection tank aeration
Multistage centrifugal and regenerative blowers
Headworks building aeration Multistage centrifugal and regenerative blowers
Aeration building Multistage centrifugal blowers
Channel aeration Multistage centrifugal and regenerative blowers
Sludge/Digestion Digester gas boosters
Compost building Single stage and multistage centrifugal blowers
Sludge dewatering building Multistage centrifugal and regenerative blowers

Spencer’s total aeration system package

  • Power Mizer® high efficiency centrifugal blowers
    Multistage blowers with three-dimensional impellers
    Superior aerodynamic design
    Special coatings available for corrosion resistance
  • Variable frequency drives
    Air delivery based on biological demand and
    system resistance
    Avoids inflexibility and waste of constant speed
    Helps end basin imbalance, foaming and undesirable
  • Dissolved oxygen control systems
    Probes, analyzers, flowmeters, motorized basin valves
    Provides input for sophisticated, fine-tuned air delivery
  • Blower & motor protection panels
    Bearing temperature and blower vibration monitors
    Oil level monitoring systems
    Motor phase protection and stator winding RTDs
    Motor overload and surge protection
  • Motor control centers
    Comprehensive, customized motor control capabilities
    Efficient modular design integrates VFDs and MCC
    Factory assembly and testing avoids field
  • Aeration system engineering
    Coordinated services of process, electrical and
    mechanical engineers
    On-staff Spencer experts in wastewater treatment and
    Programming specialists for airflow control logic
  • Electrical controls design expertise
    UL/CUL Listed control panels with PLCs and
    operator interfaces
    SCADA system tie-ins
    Flow and pressure transmission systems
  • Mechanical system components
    Inlet filters, inlet and discharge silencers
    Isolation valves, check valves, throttling valves
    Expansion joints
    Temperature and pressure monitoring systems

Methane – noxious pollutant or potent energy source?

Anaerobic digesters at wastewater treatment plants create a gaseous byproduct that is typically 65–70% methane and 25–30% carbon dioxide, plus particulates, moisture, oils and a little hydrogen and nitrogen. This mixture is a serious pollutant, but it’s also a powerful, inexpensive fuel for boilers, gas turbines, micro-turbines, sludge heaters, fuel cells and auxiliary power.


But first, you have to establish a stable supply at a boosted pressure. Our digester gas boosters are so effective at this, we have seen engineering specifications that read: “Sludge gas booster blowers shall be The Spencer Turbine Company, Model GH, or equal. Engineer knows of no equal.”

To deal with the highly corrosive and flammable gas, the gas booster is made of stainless steel with anodized aluminum fans and Inconel electrical connectors. An explosion-proof motor is located inside the gas booster housing, where it is cooled by the digester gas flow. Spencer’s completely hermetic design has zero leakage to the environment.

Spencer supplies its digester gas boosters as a complete turnkey module, skid-mounted and ready for utility hookups. Each package has its own control panel, hermetically sealed gas booster, isolation valves and other customized components such as a gas aftercooler/intercooler and stainless steel piping.

If your system has varying combustion fuel requirements, Spencer engineers can add a recirculation system with bypass piping. The bypass loop keeps gas flowing through the gas booster at all times for motor cooling, even when output flows are reduced.

Spencer digester gas booster advantages

  • Multistage, continuous-duty gas booster
  • Explosion-proof motor and controls
  • Hermetically sealed for zero leakage
  • Self-contained, prewired and prepiped
  • Very high corrosion resistance
  • Customized for new or retrofit installations

Natural gas dilution system when flow is low

Being a biological process, digester gas production can be variable and unpredictable. This creates a problem if the output demand remains constant. A Spencer natural gas dilution system keeps your system online by diluting natural gas with air, creating a temporary replacement fuel with matched BTUs to digester gas.

Like Spencer’s digester gas booster, the natural gas dilution system is furnished as a skid-mounted package. All system components are mounted and interconnected on a common skid that is designed to fit the exact dimensions of a new or retrofit installation.

Landfill gas extraction – another Spencer innovation

In municipal landfills, decaying organic matter produces a methane-rich gas similar to digester gas. Spencer has devised an effective technique for extracting and delivering this gas to accomplish two environmentally significant goals: reducing greenhouse gases and developing alternative, renewable energy sources. Our high-efficiency Power Mizer blowers are specially equipped with corrosion-resistant coated impellers and sealed to minimize leakage.

The rest of the story – more municipal Spencer contributions

Spencer product/application
Water treatment plants
Power Mizer blowers provide air for filter cleaning in air scour/filter backwash systems
Public schools Central vacuum cleaning systems for indoor air quality improvement, facility-wide sanitation, liquid spills pickup, vacuum-assisted shop tools
Public transportation Central vacuum systems with extra-long hoses to clean bus fleets and rail cars
Police and fire facilities Central vacuum systems for quiet, thorough cleaning of Call Centers, protecting sensitive communications equipment from dust contamination
Theaters, public halls
Central vacuum systems can be ideally configured for cleaning long rows of seats and carpeted or bare floors


Power Mizer® aeration blower for municipal wastewater treatment has a companion Spencer control system with PLCs, dissolved oxygen control logic, operator interface keyboards, modem software for factory communication and motor control centers.


Spencer central cleaning systems for schools turn classrooms into cleanrooms with their high-powered cleaning ability and specialized tools for carpeted floors and other surfaces.


Spencer natural gas dilution systems give municipalities the ability to utilize digester gas as their primary fuel, with natural gas as a supplementary  backup when needed.


Digester gas boosters help municipalities develop a new fuel source from their sanitary landfills and wastewater treatment plants.


Complex Spencer control instrumentation was part of a $1 million municipal wastewater aeration system upgrade. All panels and circuitry were designed and built by Spencer.