TECHNOLOGY FOCUS - ENVIRONMENT - Preferred Method: The acclimation bioreactor system, i.e. a solid-liquid retention membrane bioreactor, is fed with the effluent to seed and acclimatize the inoculum to the particular effluent to be treated, prior to release of inoculum into the hydrolysis system. The bioreactor system is seeded with inocula comprising mixed liquor suspended solids (MLSS) at 1000-20000, preferably 10000 mg-L-1, dependent on the effluent source and system volume. A feed from the membrane bioreactor system to the hydrolysis system is intermittently opened to seed fresh microorganisms from the filtration area, as required by effluent feed characteristics. The effluent feed is provided to the acclimation bioreactor system at a rate of 1-100% v/v/h, dependent on the effluent source and system volume. The effluent feed is provided to the hydrolysis system at a rate of 1-100% v/v/h, dependant on the effluent source and system volume. Mixed liquor from the bioreactor acclimation system is transferred continuously or intermittently to provide fresh microorganisms to the hydrolysis system, as dictated by effluent feed characteristics and conversion rates. The feed from the acclimation bioreactor system is trickle-fed as the mixed liquor into the hydrolysis system on a continuous or intermittent basis. The feed from the bioreactor is trickled into the hydrolysis system at a rate of 1-20, preferably 5% v/v, dependant on the effluent source and system volume. The microorganisms are cultured in the acclimation bioreactor system at a concentration of 0.01-20 g-L-1, preferably 10000 mg-L-1 but typically dependent on the effluent source and system volume. The microorganisms are held in the hydrolysis system at a concentration of 10-20000, preferably 10000 mg-L-1. The wastewater treatment process also includes monitoring the composition of the microorganism population in the bioreactor system at set intervals of 24 hours to 20 days using molecular techniques; obtaining a sample of the microorganism population from the bioreactor system and subjecting the samples to DNA analysis, lipid analysis, and/or protein analyses; and optimizing operation of the acclimation bioreactor system and the hydrolysis system in terms of residence time, cross-flow velocity, transmembrane pressure (TMP) and loading rates, where optimal microbial populations associated with the greatest productivity and process efficiency for a given effluent are maintained. The analyses include phospholipid fatty acid analysis (PLFA) for identifying the relative proportions of the major microbial groups; ribosomal DNA fingerprinting using 16S/18S rDNA for indicting variation at the specific microbial strain level; techniques from community DNA hybridization, %G+C profiling, restriction digestion and sequence comparisons, amplified ribosomal DNA restriction analysis (ARDRA), terminal restriction fragment length polymorphism (T-RFLP), ribosomal intergenic spacer analysis (RISA), or various combinations of these techniques; or electrophoretic separation based on melting (TGGE) or denaturing (DGGE) behavior. The bioreactor is provided with ceramic or polymeric membrane type(s), preferably a tubular, hollow fiber or flat sheet membrane having an average pore size of 0.01-5 mu m and a narrow pore size distribution of plus minus 0.01 mu m. The membrane provided is used as a substratum for the seeding inoculum retention. The specific surface area of the membrane provided is system volume-dependent and calculated based on maintaining a permeate flux of 1-50 L-m-2-h-1. The membrane bioreactor is operable with the mixed liquor contacting the membrane surface internally or externally.