The Allentown Wastewater Treatment Plant in Pennsylvania is one of at least
122 wastewater plants generating
renewable electricity and heat from CHP
Wastewater treatment plants are an essential part of urban and rural
communities. Wastewater treatment plants, either under municipal or private
ownership, process residential, commercial, and industrial wastes for
conversion into benign liquid, gas and solid waste streams. Although the
plants can be very energy intensive, the treatment process produces methane
as a byproduct, which can be burned to generate electricity. The waste heat
from the electricity generation can then be used to meet plant thermal
requirements such as digester and space heating loads. Making use of the
waste heat from onsite electricity production increases fuel efficiency and
decreases energy costs.
Facts and Figures
Opportunity for Combined Heat and Power
CHP is an attractive option for wastewater plants that have, or are
planning to install, anaerobic digesters. The biogas from the digester can
be used as fuel to generate electricity in a CHP system. The thermal energy
produced by the CHP system is then typically used to maintain the digester
temperature, as well as for space heating in other plant buildings. A
well-designed CHP system using biogas offers many benefits for wastewater
treatment plants because it:
- Offers savings on electricity bills.
- Displaces purchased fuels for thermal needs.
- May qualify as a renewable fuel source under state renewable
portfolio standards and utility green power programs.
- Enhances power reliability for the plant.
- Produces more useful energy than if the wastewater plant were to use
biogas solely to meet digester heat loads.
- Reduces emissions of greenhouse gases and other air pollutants,
primarily by displacing utility grid power.
Wastewater treatment plants are critical for maintaining public
sanitation and a healthy environment, and must be able to operate in the
event of a natural or man-made disaster, as well as a utility power outage.
Because of CHP's ability to produce electricity and heat on site, it is a
valuable infrastructure addition for wastewater treatment plants.
The wastewater treatment plant for the City of Allentown, Pennsylvania
produces biogas as a byproduct of the wastewater treatment process. This
biogas is used to fuel a 360-kW microturbine CHP system to produce
electricity, and the heat is recycled back to the plant's anaerobic digester
and buildings. A detailed project profile is available at