NOVELTY - An integrated process for production of biogas and energy, and integral recovery of chemical compounds and fertilizers from olive mill wastewaters, involves pre-dilution, centrifugation, selective fractionation, pretreatment in aerobic and anaerobic attached-biomass columns (CAA,CAN) and tray separation column (CAS), anaerobic biodigestion for biogas and fertilizer production, cogeneration for production of thermal and electrical power vector, and production of water reusable in the process, having hydrochemical characteristics suitable for civil use.    USE - Integrated process for production of biogas and energy and integral recovery of chemical compounds and fertilizers from olive mill wastewaters (OMW) coming from olive oil production wastes obtained through two-phase process or three-phase process, with possible mixture with olive husks and leafs.    ADVANTAGE - The process enables efficient exploitation of waste for the production of biogas and fertilizers having high quality and high availability in the soil, with optimized energetic yield. The extraction technology allows to obtain ultrapure water to be recycled in the productive process or to be used for the market of functional beverages. The method standardizes inoculums, which allows the process continuity without penalizing the biogas yield.    DETAILED DESCRIPTION - An integrated process for production of biogas and energy, and integral recovery of chemical compounds and fertilizers from olive mill wastewaters (OMW) coming from olive oil production wastes obtained through a two-phase process or three-phase process, with possible mixture with olive husks and leafs, involves pre-dilution, centrifugation, selective fractionation, pretreatment in aerobic and anaerobic attached-biomass columns and tray separation column, anaerobic biodigestion for biogas and fertilizer production, cogeneration for production of thermal and electrical power vector, and production of water reusable in the process, having hydrochemical characteristics suitable for civil use. Selective fractionation is for the recovery of polyphenol compounds through a membrane process and adsorption on resins. Pretreatment is carried out in aerobic and anaerobic attached-biomass columns and tray separation column. INDEPENDENT CLAIMS are included for the following:    (1) use of pool of microorganisms to be periodically inoculated in the reactors; and    (2) method of standardization of biomass entering the anaerobic digestion phases.    DESCRIPTION OF DRAWING(S) - The drawing shows a block diagram of the central section of integrated process of olive mill wastewater treatment.    Aerobic attached-biomass column (CAA)    Anaerobic attached biomass column (CAN)    Tray separation column (CAS)    Anaerobic digester (DG1)    Methanogen anaerobic digester (DG3)