Application of reverse osmosis and nanofiltration techniques at municipal drinking water facilities

Abstract

Main disadvantages of state of the art membrane techniques are discussed with respect to the problem of concentrate disposal. Possible ways to improve conventional membrane techniques and to radically decrease the number of effluents discharged are proposed. Application of newly developed “open channel” membrane modules that do not contain “dead” areas enables us to develop and implement into practice new techniques to reduce and even utilize concentrates of membrane units. Experiments demonstrated a possibility to reduce concentrate flow due to deposition of excessive calcium as calcium carbonate on seed crystals in the reactor. Flow diagrams for different cases of natural water composition are described and discussed that demonstrate newly developed techniques to produce drinking quality water using reverse osmosis and nanofiltration membrane facilities with high recoveries.