Application of combined physicochemical techniques for the efficient treatment of olive mill wastewaters

AbstractOlive Mill Wastewaters (OMW), produced from olive processing for the extraction of olive oil by units scattered in the Mediterranean countries, is a hardly degradable byproduct due to very high concentration of organic load of complex composition. Several treatment methods have been proposed for the efficient treatment of OMW, but because of the high operational cost, the application of these methods seems to be prohibitive, as olive mills are small family units and operate only 3–4 months per year. In the present work, the implementation of a combination of physicochemical treatment methods is proposed for the effective treatment of OMW. Initially, a membrane filtration process was used (ultrafiltration, nanofiltration, and reverse osmosis membranes) for the fractionation of OMW in concentrate and permeate streams. OMW was thus sufficiently treated and as a result the final permeate of the reverse osmosis was a pure water stream appropriate for irrigation purposes or for reuse in the OMW premises...