The biggest investor put up $4 million, and it wasn't even Waste Management. Therefore WM invested something less than $4 million.
Waste Management is famous for throwing pocket change at many waste-to-energy gambles (probably for publicity) throughout the years, most of which (if not all) have been failures and they continue to do so by the dozen, literally:
It's called greenwashing -- and Waste Management is no stranger to it. It likely allows them to win lots of waste contracts with governments and tax breaks because they are a "green" company -- you all I'm sure have seen their TV ads bragging about how much they care.