A working pontoon raft has frame that supports a plurality of high speed evaporator fans. An on board pump draws wastewater from under the raft and feeds it to the fans. Large amounts of wastewater from industrial reservoirs, such as oil drilling reservoirs, are evaporated into the air in an environmentally friendly manner. Power is supplied to the raft via hydraulic lines. A land base generator supplies the hydraulic power. The entire system fits on a custom trailer.