TECHNOLOGY FOCUS - ENVIRONMENT - Preferred Method: The method further comprises adding nutrients such as carbon, nitrogen, phosphor and mineral sources for the antibiotics non-resistant bacteria and/or enzymes.The enzymes are proteases, cellulases, alpha-amylases and/or lipases.The antibiotics non-resistant bacteria are sensitive to antibiotics used in human and veterinary medicine, sensitive to antibiotics used as alimentary additives in stock farming and/or sensitive to antibiotics used for the treatment of plant diseases.The antibiotics non-resistant bacteria are sensitive to at least 8 of the antibiotics chosen from ampicillin, augmentin, benzylpenicillin, cefalexin, cefazolin, ciprofloxacin, clarithromycin, doxycylin, enrofloxacin, erythromycin, florfenicol, furanes, gentalycin, lincomycin, oxacillin, spiramycin, sulphamides, tetracycline, trimethoprime, tylosin, vancomycin, and virginiamycin, or gentamycin.The antibiotics non-resistant bacteria are not genetically modified bacteria containing a nucleic acid sequence encoding a resistance factor or a portion of a resistance factor to an antibiotic.The solid waste residue is submitted to a preliminary step of complete or partial sterilization, including a physical treatment (such as sonication, high pressure treatment, heat treatment), a chemical treatment (addition of peroxides, alkaline hydrolysis) or a biological treatment (composting, or anaerobic digestion).The concentrations of enzymes are comprises of 0.1-1% as compared to the concentration of organic matters present in the effluent or residue to be treated. EXAMPLE - Two different strains of Acinetobacter were studied, the resistant strain P and sensitive strain C1. The activated sludge used was sampled in the secondary clarifier of the waste water treatment plant. The laboratory medium composed of casein, yeast extract and glucose was inoculated either with the resistant strain of Acinetobacter P or the sensitive one C1. Bacterial growth was monitored by measuring the optical density at 585 nm. Amoxicillin and beta-lactam antibiotic, were used at concentrations 0, 10, 50 and 200 ppm. The resistant strain P was able to grow at an antibiotic concentration of 10 ppm, the growth of the sensitive one was completely inhibited at that concentration. The waste water medium was inoculated with either the resistant strain of Acinetobacter P, the sensitive one C1 or a mixture of them (C1+P). The bacterial growth was measured by following the oxygen uptake as a function of time. The proportion of resistant and sensitive bacteria was determined at different times. The method used to determine this proportion was based upon the bacterial enumeration of a sample spread upon the surface of two different agar media: the first one was prepared with an amoxycillin concentration of 10 ppm, the other one without any addition of antibiotic. The bacteria enumerated upon the first agar media corresponded to the resistant one, those enumerated upon the second agar medium corresponded to the complete mixture, the difference measured between the two agar media corresponded to the sensitive bacteria. The inoculum was composed of 100% of sensitive or resistant bacteria for the corresponding pure culture, 87% of resistant bacteria and 13% of sensitive bacteria were used for inoculating the mixed culture. The bacterial growth rate measured by following the oxygen uptake in the waste water medium was faster, when only the sensitive bacteria C1 were used for the inoculation. The latent period was longer and the growth rate was slower for the medium inoculated with only resistant bacteria P. An intermediate situation was observed when the mixture C1+P was used. The proportion of the two bacteria in the mixed culture was determined 48 hours after the inoculation. A drastic change in the proportion of the two bacterial populations was observed. The sensitive bacteria which represented only 13% of the total population at the beginning of the culture became the main population (84%) at the end of the culture. The addition of small concentrations of sensitive bacteria in a waste water reduced the proportion of resistant microorganisms.