Engineers are finalizing design for a 17-mile-long pipeline that will deliver methane gas from a landfill in Muskego, Wis., to fuel a wastewater treatment plant in Milwaukee. The pipeline is the first step in an $80-million investment that will save the Milwaukee Metropolitan Sewerage District (MMSD) at least $148 million over the next 20 years by enabling its Jones Island plant to generate its own heat and electricity by burning landfill-generated methane instead of natural gas. In addition to saving money, the plant will also cut greenhouse-gas emissions by 500,000 tons a year. MMSD tentatively plans to seek bids from
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.