Patent EP-1787962-A1 (EP)
Inventor: KOCH ROLAND PROF DR-ING
IPC: C02F101/10
Filed: 2005-11-17
Abstract: The purification of waster water in small-scale clarifier for eliminating phosphorus and its compounds, comprises slow decomposing of plastic-granulates/-compounds (4) filled in a reactor (2) of the clarifier, in the waste water, and/or degradation of the granulates or the compounds by microorganisms to release aluminum sulfate precipitating agent bound in the matrix of the granulates/compounds. The purification includes pre-clarification, after-clarification and biological purification. The plastic granulates/-compounds in aqueous solution in the clarifier are diminished slowly by hydrolysis. The purification of waster water in small-scale clarifier for eliminating phosphorus and its compounds, comprises slow decomposing plastic-granulates/-compounds (4) filled in reactor (2) of the clarifier, in the waste water and/or degradation of the granulates or the compounds by microorganisms to release aluminum sulfate precipitating agent bound in the matrix of the granulates/compounds. The purification includes pre-clarification, after-clarification and biological purification. The plastic granulates/-compounds in aqueous solution in the clarifier are diminished slowly by hydrolysis. For the increase of the hydrolysis speed, the crystallinity and/or the molar mass is degraded and/or the number of ester bonding in the polymers are increased and a co-polymerization with hydrophilic polyalcohols or blending with native and/or thermoplastic starches is carried out. The hydrolysis speed of polyester urethanes is increased by the addition of a thermoplastic starch. polylactide (PLA) of the granulates/compounds is made via a ring-opening polymerization using co-rotating, closely inter-meshing single- or twin-shaft extruder. The lactide is mixed with a stabilizer and with a catalyst-cocatalyst-system dissolved in solvents. The lactid mixture is transferred over a loss-in-weight feeder to a single- or twin-shaft extruder exhibiting a pressure- and a temperature sensor and a control- and process regulation mechanism, and mixed in a static mixer to form polylactide. The production of granulates and/or the compounds are carried out from polyesters and starch by the extruders. The agent is supplied to the extruders in the entrance zone by a separate metering unit and is mixed together with the plastic raw material before the extrusion process. The plastic raw material or a part of the plastic raw material is dosed to the extruders in the entrance zone. The agent and if necessary the other part of the plastic raw material mixed with the agent, is supplied to the extruders via a metering device for feeding side stream. The plastics and the agent in the extruders are mixed by a concept screw mixing, which exhibits combination of mixing- and/or kneading element. The agent containing plastic body is manufactured by injection molding, is cut into small solid particles by granulation method or is pressed or is formed by another method. The agent has a diameter of 5 cm and has a shape of sphere or cylindrical or similar form. The reactor has constant or cyclic compressed air supply (3) in its lower area and is used both in new water treatment plant and old plant. An independent claim is included for a device for carrying out wastewater purification by using the above process.