824 PATENT ABSTRACTS

Especially good results are obtained when a membrane composed of porous hollow fibers is used as the gas-permeable membrane.

4748127

PROCESS FOR THE DETECTION OF BIODEGRADABLE AND

TOXIC SUBSTANCES IN AQUEOUS SOLUTIONS

Friedrich Siepmann, Michael Teutscher, D 6100 Darmstadt, Federal Republic Of Germany

A process and apparatus for measuring the degree of pollution, the degradableness, and the level of toxicity of aqueous liquids such as ef- fluent. A partial stream is withdrawn from the li- quid undergoing examination and diluted with biologically neutral water. The diluted partial stream is oxygenated and continuously flows through a biological bath in a reaction vessel having a constant living mass. The dilution of the partial stream is regulated in such a manner through measurement of the oxygen content up- stream and downstream of the reaction vessel, that with constant volume flow through the reac- tion vessel, the difference between the measurement values obtained remains essen- tially constant at a predetermined value, so that the amount of dilution serves for the indication of the level of pollution. Additional reaction ves- sels connected in parallel or in series with the first reaction vessel and having associated oxygen electrodes allows measurement of the toxicity and degradableness of the pollution.

4749494

TREATMENT OF WASTE WATER BY THE ACTIVATED SLUDGE

PROCESS

Takaharu Tomoyasu, Yuzaburo Kumagai, Shiro Honda, Hikoyosh Kanayama, Chiba, Japan assigned to Mitsui Sekiyu Kagaku Kogyo Kabushiki Kaisha

An activated sludge treatment process for waste water characterized in that, in the waste water treatment where waste water containing organic matter is introduced into an activated sludge reaction tank and the excess sludge formed in the reaction tank is introduced into a sludge diges- tion tank to effect the digestion of said excess sludge by intermittent aeration with air, a part of the digestion tank liquid is passed through a fil-

tration apparatus having an ultrafiltration mem- brane, the filtrate passed therethrough is withdrawn outside the system, the remainder is circulated to the digestion tank to maintain the liquid volume of the digestion tank at a definite level, and when the amount of the reaction tank liquid introduced from the reaction tank into the digestion tank is taken as W 1, the digestion tank liquid is returned in an amount of (0.2-0.8)Wl to the reaction tank, and thus the amount of excess sludge to be treated outside the system can be reduced or can be completely eliminated.

4750454

MANURE DIGESTER AND POWER GENERATING SYSTEM

Peter Santina, Anil Chatterjee assigned to San- tina and Thompson Inc

A manure digester and power generating system includes a mixing tank for receiving manure, a closed, anaerobic manure digester tank of fixed volume, and a gas-fueled engine and a generator coupled to the engine, for generating electrical power. Manure is scraped into the mixing tank daily, where it is mixed with water to produce a manure slurry of desired consistency, and heated to a prescribed temperature. The digester tank is of fixed volume and may be of a generally rounded cross-sectional shape and elongated in length, and into its inflow end the contents of the mixing tank are transferred daily, on a daily batch basis. Anaerobic-digesting microbes are maintained in the digester tank to digest the manure slurry and produce methane gas and by- products. Temperature in the digester tank is maintained at about 90 degrees to 100 degrees F. Effluent by-products are discharged out the out- flow end of the digester tank, and methane gas is drawn off the digester tank and fed to the gas- fueled engine, the exhaust heat from which pre- ferably is used to heat the slurry in the mixing tank.

4752316

APPARATUS AND PROCESSES FOR COMPRESSING AND/OR

BIODIGESTING MATERIAL

Charles J Plovanich, Guy H Ossont, Keith C King, Robert H Irwin, Walter V Knopp assigned to Revere Copper and Brass Incorporated