Processes of Valorization and Management of Olive By-Products: The Pomace and Olive Mill Wastewater

Abstract

AbstractThe valorization of different organic residues like municipal solid wastes, sewage sludge, and olive tree by-products, specifically pruning products; pomace and olive mill wastewater, more commonly known as the vegetation water of olives or margins is becoming more and more required in the different modern communities and relevant and crucial in terms of environmental preservation. The treatment of these wastes should be associated and viewed under two simultaneous approaches: good disposal of these cumbersome and problematic residues and righteous valorization by considering economic profitability. Thus, pruning products and pomace could be an important and valuable source of food for animals, a second-grade oil source for cosmetic soap making, production of biogas, and electrical energy from all these problematic residues. Besides, the removal of polyphenols from olive mill wastewater would have a double interest: to solve a major environmental problem and to recover and valorize the olive mill wastewater for later applications in food animal processing and soil amendments and fertilization. Using margins as process watering during composting or co-composting, stages of pre-fermentation-fermentation, and maturation are well recommended to obtain a compost of high soil fertilizing quality. The advantage of compost made from margins is the absence of pathogenic microorganisms and high levels of phosphorus and potassium content, unlike urban solid waste. About municipal solid wastes, it is recommended and interesting to associate two kinds of wastes by co-composting for example, vegetable gardens-pruning products, pomace-municipal solid waste, and green wastes-olive mill wastewater…, to get a mixed compost of good physical–chemical and biological qualities, safe and useful for agricultural soil fertilization.KeywordsOrganic residuesOlive tree by-productsOlive mill wastewaterCo-compostingSoil fertilization