Abstract: Process and apparatus is disclosed for removing pollutants from a waste gas stream comprising culturing in a rotary biocontactor a biomass capable of assimilating the pollutants and producing harmless metabolites. The waste gas stream is brought into contact with the biomass within the biocontactor. The biocontactor includes a plurality of discs mounted for rotation within the biocontactor. The waste gas stream in passing over the exposed biomass on the disc results in the pollutants being absorbed by the biomass. In turn the biomass assimilates the pollutants and produces harmless metabolites. The gas stream with a substantial percentage of pollutants removed therefrom and containing any gaseous metabolites is exhausted from the biocontactor.

Abstract: A liquid purification system using buoyant filter media for removing suspended solids from liquid comprising a vessel having a wastewater inlet and a clarified effluent outlet. Baffles are provided in the vessel to define an upflow region for the wastewaters over a weir into a downflow region for subsequent removal by the effluent outlet. Buoyant media is provided in the upflow and downflow regions where the buoyancy of the media in the upflow region carries some of the buoyant media over into the downflow region until equilibrium is reached. A device may be provided for the continuous removal, washing and return of buoyant media to the system.