Treatment of Olive Mill Wastewater from Traditional Presses (Maâsra) Using Filtration and Adsorption Processes

Abstract

<abstract><title><italic>Abstract. </italic></title> Olive mill wastewater (OMW) is the liquid waste from the production of olive oil. The wastewater is rich in organic matter and polyphenols [Chemical Oxygen Demand (COD) = 100 g L^-1; total phenols = 15 g L^-1]. The direct discharge of OMW from many of the 15,000 traditional olive mills in operation in Morocco is a significant cause of environmental degradation. Column and pilot studies were conducted to characterize OMW treatment through sand filtration and carbon adsorption. A series of three 60 cm sand filters in series were shown to be capable of reducing COD, total phenols, and Total Suspended Solids (TSS) by 64%, 69%, and 88%, respectively, when dosed at 8 cm every 4 days with no clogging observed after 7 dosing cycles; however, clogging was observed at a 20 cm loading rate. Column and pilot adsorption studies with activated carbon were also carried out and were shown to be effective at reducing COD and total phenol to non-detect levels while reducing Total Solids (TS) by 85% with 119 g of activated carbon required to treat 1Â L OMW. A passive technology comprised of three sand filters in series followed by an activated carbon filter is proposed as a solution to treat OMW from traditional olive mills.