Stable, high-flux membranes for wastewater renovation by reverse osmosis were required to meet or exceed: fluxes greater than 60 gal/sq ft/day with no more than a 20% increase after one year; Rejection of 60% of sodium chloride; and Rejection of 90% of sodium sulfate. All testing was performed at 600 psi, with 1000 ppm feed solutions. These specifications were met by three cellulose based membranes. Flux losses over short periods were extrapolated to yearly values and ranged from 12-18%. However, periodic cleaning with a laundry enzyme pre-soak was necessary as the flux rates initially declined very rapidly. Cleaning restored the membranes to 80 to 90% of the initial values. Daily cleaning maintained a five day series of tests at nearly constant levels. The best of the three membranes tested rejected 90 to 97% of TDS, 70 to 100% of COD, 86 to 96% of ammonium ion, 72 to 99% of nitrate ion, and 97 to 99% of total phosphate. Techniques were explored for attachment of proteolytic enzymes to cellulose acetate membranes to render them resistant to colloid fouling. The proteolytic enzyme trypsin was chemically attached to the active layer surface of a membrane prepared from the N-hydroxysuccinimide ester of cellulose acetate hydrogen succinate. The resulting enzymatic membrane displayed hydrolytic activity. No cost estimates were presented for this type of treatment process. (WRSIC abstract)