Abstract: In the operation of a recycling anaerobic filter for treating aqueous waste streams, the rate of production of methane is measured continually at frequent intervals and the COD feed rate is varied to maintain a predetermined, timed, relationship between that varied feed rate and the measured methane production rate.

Abstract: Treatment of waste streams, particularly acidic petrochemical wastes, in anaerobic filter at high loadings with high rates of recycle. The effluent from the top of the filter is passed into a gas-disengaging-solids-settling zone containing a quiescent body of the liquid of said effluent. Particles of solid biomass settle in that liquid body and are withdrawn, with the liquid, and recycled to the base of said filter together with fresh acidic waste and added inorganic alkaline material. The outfall from the filter is fed to an aerobic digester and the resulting activated sludge is recycled to the filter. The alkaline material is preferably magnesium oxide or carbonate. Sodium formate may also be used as the alkaline material.

Abstract: Treatment of waste streams, particularly acidic petrochemical wastes, in anaerobic filter at high loadings with high rates of recycle. The effluent from the top of the filter is passed into a gas-disengaging-solids-settling zone containing a quiescent body of the liquid of said effluent. Particles of solid biomass settle in that liquid body and are withdrawn, with the liquid, and recycled to the base of said filter together with fresh acidic waste and added inorganic alkaline material. The outfall from the filter is fed to an aerobic digester and the resulting activated sludge is recycled to the filter. The alkaline material is preferably magnesium oxide or carbonate. Sodium formate may also be used as the alkaline material.

Abstract: In the operation of a recycling anaerobic filter for treating aqueous waste streams, the rate of production of methane is measured continually at frequent intervals and the COD feed rate is varied to maintain a predetermined, timed, relationship between that varied feed rate and the measured methane production rate.

Abstract: A biological filter apparatus, and process for using the same, wherein organic pollutants in a waste water stream may be biologically degraded by a biomass of suitable microorganisms located on the surface of a packing. The filter comprises a sealed vessel in which the packing having the biomass thereon is located, and the waste water, mixed with several volumes of liquid recycle, is allowed to trickle downwardly through the packing countercurrently to ascending gases, effluent liquid is removed from the bottom of the vessel at a rate sufficient to maintain the level of effluent liquid below the packing in order to prevent the packing from being submerged in liquid. The apparatus and process are applicable to the anaerobic methanogenic processes wherein methane is produced as a product; and are also applicable to non-methanogenic processes which are conducted in the absence of added molecular oxygen wherein combined nitrogen is converted to molecular nitrogen.

Abstract: Treatment of waste streams, particularly acidic petrochemical wastes, in anaerobic filter at high loadings with high rates of recycle. The effluent from the top of the filter is passed into a gas-disengaging-solids-settling zone containing a quiescent body of the liquid of said effluent. Particles of solid biomass settle in that liquid body and are withdrawn, with the liquid, and recycled to the base of said filter together with fresh acidic waste and added inorganic alkaline material. The outfall from the settling zone is fed to an aerobic digester and the resulting activated sludge is recycled to the filter. The alkaline material is preferably magnesium oxide or carbonate. Sodium formate may also be used as the alkaline material.