Turning Poo Into Power

Green Bay, WI - Over the past two years, Green Bay Metropolitan Sewerage District (GBMSD) staff have been evaluating plans to replace its current solids handling equipment used in the treatment process. GBMSD needs to replace its current system because equipment has reached the end of its useful life, it must comply with stricter environmental air permit standards by May 2016, and it has triggered a regulatory requirement to increase capacity because it operates at more than 90% capacity daily.

The new solids handling plan selected recovers resources and generates electricity. The project is a Resource Recovery and Electrical Energy generation system known as the R2E2 Project. Director of Operations, Pat Wescott said, "We have shifted our thinking process to view what comes to our facility, not as a waste, but as a resource to be recovered and reused."

The R2E2 Project involves building two anaerobic digesters, which break down biodegradable material in the absence of oxygen, and reduce the volume of material to be processed. In addition, the digesters will produce a methane gas, which will be captured and processed into a biofuel, used to produce electricity.

GBMSD will also recover the heat from a new incinerator, which replaces its two existing 35-year-old incinerators. Through thermal processing, the heat from the system will be recovered and used for building heat or electricity production.

The new equipment will be more efficient, effective, and meet the new, stricter environmental air permit standards.

The benefits of the system are:

  • It will generate about 50% of GBMSD's energy in the first year (equivalent to about $2.2 million of energy)
  • It will reduce greenhouse gas (CO2) emissions by about 22,000 metric tons per year, which is the same as removing about 15,000 vehicles from the road
  • It is the lowest cost plan over a 20-year planning period
  • With producing much of its own energy, GBMSD will be able to minimize expenses as energy costs rise in future years
  • It will use about 90% less natural gas than the current system

The project cost is $147 million. "It is an expensive project, but is necessary. We are making certain we move forward with the most progressive and cost-effective plan possible," said Executive Director, Tom Sigmund. "There is an even greater cost of not doing anything by having the current system fail."

The project will be paid for through GBMSD's municipal wholesale rate charge; that's the rate it charges its direct customers. Based on current conditions, GBMSD anticipates its wholesale rate will increase about 9% each year until 2016.

It is important to note that GBMSD does not bill residents and businesses directly for wastewater treatment service so rates will vary from municipality to municipality. Generally, GBMSD's wholesale rate makes up less than half of the average household's sewerage charge, which is part of a resident's combined water and sewer bill.

Over the next three months, GBMSD will be hosting a series of public informational meetings on the R2E2 Project. The first public informational meeting will be held on November 28 from 2 p.m. to 4 p.m. at the Ashwaubenon Village Hall. For more information, visit www.gbmsd.org.

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