Patent DE-102009017125-A1 (DE)
Title: Processing surface water, industrial water, brackish water and/or grey water to drinking water, comprises initially sucking the water by prefiltration, and subsequently subjecting the sucked water to microfiltration and/or ultrafiltration
Inventor: HEYBACH KLAUS
IPC: C02F1/76
Filed: 2009-04-15
Abstract: The method comprises initially sucking the water by prefiltration, and subsequently subjecting the sucked water to microfiltration and/or ultrafiltration under pressure and then to nanofiltration, where an antiscalant is dosed to the water in a flow direction before the nanofiltration and a substance providing chlorine is dosed to the water after the nanofiltration. A free chlorine-eliminating chemical is provided for the purpose of dosage in the flow direction before the nanofiltration, so that the water to be prepared contains chlorine. The water is subjected to an UV-sterilization. The method comprises initially sucking the water by prefiltration, and subsequently subjecting the sucked water to microfiltration and/or ultrafiltration under pressure and then to nanofiltration, where an antiscalant is dosed to the water in a flow direction before the nanofiltration and a substance providing chlorine is dosed to the water after the nanofiltration. A free chlorine-eliminating chemical is provided for the purpose of dosage in the flow direction before the nanofiltration, so that the water to be prepared contains chlorine. The water is subjected to an UV-sterilization after the nanofiltration. The retentate occurring during the nanofiltration is partially recirculated to the water before the microfiltration and/or ultrafiltration or between the microfiltration and/or ultrafiltration and the nanofiltration, where the antiscalant and optionally the free chlorine-eliminating chemical are dosed to the retentate before recirculation. The part of the retentate is transferred to receiving water. The retentate is partially supplied to a liquid container, in which the antiscalant and optionally the free chlorine-eliminating chemical are dosed to the retentate, where the retentate is pumped from the liquid container and then is recirculated. The retentate is sub-divided into a first- and a second retentate partial flow above the liquid container. The first retentate partial flow is supplied to the liquid container and the second retentate partial flow is supplied to a jet pump for pumping the retentate from the liquid container. The dosage step is carried out using a tube pump and/or a piezo-membrane pump. During the prefiltration, 80-90% of the microbiological germs contained in the water are held back. During microfiltration and/or ultrafiltration and nanofiltration, the microbiological germs are held back in a circumference, so that the water is delivered up to 95-99% from the germs after the microfiltration and/or ultrafiltration and up to 99.9% from the germs after the nanofiltration. The prefiltration and microfiltration and/or ultrafiltration are optionally intermittently flushed back using filtered backwashing air that is filtered using microfiltration and is stored in a pressurized container under overpressure. The water is supplied to a storage container (5) after sucking by prefiltration and then initially transferred to the microfiltration and/or ultrafiltration. An independent claim is included for a device for processing surface water, industrial water, brackish water and/or grey water to drinking water.