Abstract: A membrane treatment plant having at least two stages (53), (69), (75) arranged serially is disclosed. Each stage (53), (69), (75) comprises at least four membrane units (55) arranged in parallel, with each membrane unit (55) having an inlet (57), a feed/concentrate outlet (59) and a permeate outlet (61). Each stage (53), (69), (75) has a common inlet header (51), (67), or (73) and a common outlet header (65), (71) or (77), with the common outlet header (65) (71) of an upstream stage connecting to the common inlet header (67) (73) respectively of an immediately downstream stage. Each membrane unit (55) has an inlet flow control valve (93) connecting between its inlet (57) and the common inlet header of the stage in which it is located, and an outlet flow control valve (63) connecting between its outlet (59) and the common outlet header stage in which it is located.

Abstract: Process and facility for treating an aqueous solution containing substantial concentrations of a variety of contaminants, including solids, semi-solids, colloids, complexes, oligomers, polyvalents, organics and monovalents, and which tend to form gels and scale precipitates when their concentration levels are increased during treatment of the aqueous solution, the process comprising the steps of: a) feeding the aqueous solution to an ultrafiltration (UF) plant and recovering therefrom an UF permeate reduced in such suspended solids, semi-solids and colloids; b) feeding the UF permeate obtained from step (a) to a nanofiltration (NF) plant and recovering therefrom an NF permeate reduced in such complexes, oligomers, polyvalents and organics; and feeding the NF permeate obtained from step (b) to a first reverse osmosis (RO) plant and recovering therefrom an RO permeate reduced in such monovalents. The process and facility may be used for treating process water from wet process phosphate acid production.

Abstract: A membrane treatment plant having at least two stages (53), (69), (75) arranged serially is disclosed. Each stage (53), (69), (75) comprises at least four membrane units (55) arranged in parallel, with each membrane unit (55) having an inlet (57), a feed/concentrate outlet (59) and a permeate outlet (61). Each stage (53), (69), (75) has a common inlet header (51), (67), or (73) and a common outlet header (65), (71), or (77), with the common outlet header (65) (71) of an upstream stage connecting to has the common inlet header (67) (73) respectively of an immediately downstream stage. Each membrane unit (55) has an inlet flow control valve (93) connecting between its inlet (57) and the common inlet header of the stage in which it is located, and an outlet flow control valve (63) connecting between its outlet (59) and the common outlet header of the stage in which it is located.