After a 10-month delay, landfill gas is now flowing through a 19-mile pipeline that runs from Muskego, Wis., to the Jones Island Wastewater Treatment Plant in the Milwaukee harbor, operated by the Milwaukee Metropolitan Sewerage District. The gas, which will be used for electricity at Jones Island, was touted as “green energy” when the project was announced in 2009. 

According to an article in the Milwaukee Journal Sentinel, the $86 million energy project is “intended to save money over 20 years by reducing the amount of more costly natural gas needed to power the treatment plant.” Savings were originally projected between $25 million and $65 million during the 20-year period. As the cost of natural gas increases, so, too, will the treatment plant’s savings. 

Currently, Advanced Disposal Services Inc., owner of the Emerald Park Landfill in Muskego, is under contract to ship a minimum of 690,404 dekatherms of landfill gas to Jones Island in 2014. That volume will slowly increase each year, to a minimum of 993,287 dekatherms in 2029, which will make the sewage plant essentially natural gas-independent. 

Additional savings will come from using waste heat in the production of Milorgranite, MMSD’s commercially sold biosolids fertilizer. 

The delay was caused by failures of three compressors, one for each of the turbines, and other technical difficulties, including Advanced Disposal’s inability to consistently provide low-moisture fuel, reported the Journal Sentinel in October. The gas processing plant at Emerald Park removes hydrogen sulfide, silicon particles and nearly all water vapor before it’s piped to Jones Island. The lengthy delay cost MMSD an additional $937,000 in unbudgeted natural gas purchases. 

The 19-mile pipeline is comprised of 13.3 miles of high-density polyethylene pipeline, which connects with 5.7 miles of old steel petroleum pipeline. Because of this, MMSD has required gas with a lower-than-industry-standard moisture dew point of minus 20 degrees to protect the steel segment. 

MMSD provides water reclamation and flood management services for about 1.1 million customers in 28 communities around the Milwaukee area. The plant’s service area covers 411 square miles and six watersheds. 

Could your municipal district benefit from a program similar to MMSD? Post a comment below.