(US5277814-A)      A low-solids water-contg. organic or sanitary waste is aerobically treated by combining with biologically inert non-friable bulking agent to have a large component with density less than water, passing an O-contg. gas through the mixture to separate and remove excess water, then reacting the resultant high solids content mixt. in the presence of an aerobic biomass.    Active biomass-coated bulking agent is sepd. from the treated waste which is recovered. The bulking agent may be polystyrene or polypropylene, opt. a closed-cell foamed polymer. The treatment is carried out with meophilic or thermophilic bacteria and the mixture is placed in a vessel with a depth of 3-20 feet.    ADVANTAGE -   Can generate and maintain an active substrate for extended periods of time, with treament in large deep beds to reduce mixing energy requirements.    (JP7265899-A)      Aerobic treatment of water contg. oily sludges and other organic waste of relatively low solids content in a high solids content reaction. The waste is mixed with an inert bulking agent in the presence of active biomass and nutrients. A gas contg. oxygen is passed through the reaction mixt. to assist in the removal of excess water from the sludge or waste to form a wetted high solids content reaction mixt. contg. the oily sludge and waste in a bed of bulking agent. Aerobic treatment converts the oily sludge to treated sludge and the bulking agent is coated with active biomass. The biomass-coated bulking agent low density component is then sepd. from the treated solids. The treated oily sludge is recovered and the active biomass-coated bulking agent having a density less than water is used for the treatment of fresh oily sludge.    USE/ADVANTAGE -   The process may take place in a closed reactor with controls to prevent environmental pollution. It generates a sustainable active biomass. Sludges may be dewatered and treated in the same reaction vessel and energy requirements are reduced.    (EP566256-B1)      A method for aerobically treating a low solids water-containing oily sludge or other organic waste which comprises combining said waste with a biologically inert, non-friable bulking agent having a component with a density less than water to form a mixture, passing an oxygen-containing gas through said mixture to separate excess water and form a high solids content reaction mixture, reacting said high solids content reaction mixture in the presence of an aerobic biomass under effective aerobic conditions to form a treated sludge and an active biomass-coated bulking agent component having a density less than water is said high solids content reaction mixture, separating by flotation said biomass-coated bulking agent component having a density less than water from said treated sludge or waste, and recovering said treated sludge or waste from said reaction mixture.