Abstract: A process for removing dissolved fluorides from an aqueous stream using at least two reactors wherein the dissolved fluoride containing aqueous feed and an unreacted aluminum containing sludge are combined in the first reactor to give a first reactor admixture after which the first reactor effluent stream is directed to the second reactor and therein combined with fresh alum and fresh sodium aluminate to give a second reactor admixture comprising a reduced fluoride aqueous solution and a partially reacted aluminum containing sludge and thereafter recovering the reduced fluoride aqueous solution and recycling at least a portion of the aluminum containing sludge to the first reactor.

Abstract: A system for preventing entanglement of a wheeled tractor with wire or other wrappings, the system having at least one cutter assembly mounted to the frame of the tractor and designed to shear wire or other materials that can lodge between the axles and wheels of the tractor. The system can have two different cutter assemblies, one as described and one that moves in a scissor-like motion in synchronization with the undulating motion of the tractor's rear axle.