Ten years ago officials with the City of Carmel, Ind., and staff at the wastewater treatment plant decided to change the solids handling system. At the time, the plant used its anaerobic digester and centri-fuge to produce Class B biosolids. The process was effective, but for final disposition the city was hauling 100 percent of its material 40 miles away for land application.“Our goal was to produce a product that we wouldn’t have to haul,” says Ed Wolfe, manager of wastewater operations. “We wanted a product with value enough that people would come and get it. We still haul some,
