NOVELTY - A waste water treatment process comprising providing bioactive material in waste water, containing microorganisms capable of removing impurities from the waste water, in which at least 40 vol.% of the bioactive material in the waste water is maintained in granular form, and passing a portion of the waste water through a membrane separator, and preventing the bioactive material from passing through it, is new.    USE - For treating waste water to produce clean water (claimed); useful for treating waste water such as sewage effluent, industrial waste water, brackish water to produce potable water and for high purity water applications such as for use in electronics manufacturing.    ADVANTAGE - The water treatment process overcomes the fouling problems associated with prior art waste treatment processes. The size of the granular particles prevents or at least inhibits fouling on the membrane. Hence, fouling problems associated with prior art are ameliorated or avoided. Such membrane fouling is minimized in the granular membrane reactor (GMBR), which can perform membrane filtration of mixed liquor in the presence of a stable granular biomass. By maintaining granular bioactive particles and using separation membrane, nearly clean effluents can be achieved with membrane filtration using, micro- or ultra-filtration membranes. The aggregation of microorganisms into compact granular biomass confers benefits such as protection against predation, resistance to chemical toxicity and better availability of carbon and energy sources for effective biological treatment. The tight packing of microorganisms within the granules can facilitate horizontal gene transfer, which in turn can enhance the ability of granules to degrade recalcitrant or toxic compounds as the genes that encode these biodegradation pathways can be more easily distributed to other microorganisms. The use of the submerged membrane with at least 40 (preferably greater than or equal to 90) vol.% of the bioactive material in granular form, significantly reduces pore blocking and the adsorption of colloids or salutes on the membrane. The reactor is capable of operating at a higher flux permeate over time relative to submerged membranes with minimal or no bioactive material in granular form. It is not necessary to utilize any carriers in the water treatment process. The method can treat any liquid media, reducing the physically, chemically and biologically removable material in it.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) a method of forming bioactive granules for use in a water treatment reactor (10) having a chamber (12) that is in fluid communication with a membrane separator (14), involving suspending bioactive seed material in waste water within the chamber, in which the bioactive seed material contains microorganisms which are capable of removing impurities from the waste water; growing the microorganisms contained within the bioactive seed material to form larger particles; and removing particles of a selected discharge particle size from the chamber while retaining bioactive particles of a selected granular size within the chamber;    (2) a water treatment system comprising a reactor having a chamber for containing waste water; bioactive material for suspension in the waste water, containing microorganisms capable of removing impurities from the waste water, in use, at least 40 vol.% of the bioactive material in the waste water is maintained in granular form; and a membrane separator in fluid communication with the chamber; and    (3) a water treatment reactor comprising a chamber containing bioactive material suspended in waste water; and a membrane separator in fluid communication with the chamber.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic diagram of a granulating membrane bioreactor.    Granulating membrane bioreactor (10)    Chamber (12)    Membrane module (14)    Waste water inlet conduit (16)    Waste water feed pump (18)    Aeration inlet conduit (20)    Flow meter. (22)