Detoxification of olive mill wastewater by adsorption on activated clay

• Published in: Euro-Mediterranean journal for environmental integration 2023-03, Vol.8 (1), p.167-177
• Main Authors: Dehmani, Younes, Arif, Soukaina, Daou, Ikram, Ed-Dra, Abdelaziz, Oirdi, Samia El, Moussout, Hamou, Hajjaj, Hassan, Filali, Fouzia Rhazi, Abouarnadasse, Sadik
• Format: Article
• Language: English
• Subjects: Activated clay; Adsorption; Aerobic treatment; Agricultural land; Agricultural wastes; Anaerobic digestion; Anaerobic treatment; Analytical chemistry; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Biological activity; Chemical oxygen demand; Chloride; Clay; Coagulation; Detoxification; Earth and Environmental Science; Earth Sciences; Environmental Chemistry; Environmental impact; Environmental Management; Environmental Science and Engineering; Evaluation; Evaporation; Flocculation; Fluorescence spectroscopy; Food industries wastewaters; Germination; Heat treatment; Infrared spectroscopy; Irrigation; Lepidium sativum; Natural environment; Olive oil; Olives; Organic matter; Original Paper; Oxidation; Parameters; Phenolic compounds; Phenols; Physicochemical properties; Pollutants; Radiation; Reverse osmosis; Scanning electron microscopy; Seeds; Semi arid areas; Semiarid lands; Spectroscopy; Sulfuric acid; Vicia faba; Waste Management/Waste Technology; Waste Water Technology; Wastewater; Water Management; Water Pollution Control; Water resources; X-ray diffraction; X-ray fluorescence
• ISSN: 2365-6433; 2365-7448
• DOI: 10.1007/s41207-023-00347-5

Morocco is among the Mediterranean countries producing olive oil. This beneficial industry for the national economy generates two residues: one solid, the pomace, and the other liquid, the oil mill wastewater (OMW). The pomace is reused in agriculture and industries, while the OMW is rejected directly into the sewer or natural environment, resulting in huge environmental impacts. To deal with this issue, several treatment processes have been established so far, including thermal (forced evaporation and coagulation–flocculation), physicochemical (aerobic treatment, anaerobic treatment, adsorption, thermal oxidation and advanced oxidation, filtration, membrane separation, and reverse osmosis), and biological processes. In this regard, this study aims to evaluate the adsorption efficiency of OMW on activated clay as an effective method to remove toxic compounds and to study the application of the treated OMW in irrigation of agricultural fields. For this purpose, clays were collected from Agourai City (Meknes Region, Morocco) activated by sulfuric acid and characterized by X-ray diffraction, X-ray fluorescence spectroscopy, Brunauer–Emmett–Teller (BET) measurements, and Fourier-transform infrared (FTIR) spectroscopy. The physicochemical parameters of OMW were also determined. Furthermore, the adsorption effectiveness of OMW on activated clay was evaluated by assessing the effect of the treated OMW on the germination of Lepidium sativum seeds and the growth of Vicia faba plants. The results of this study show that the adsorption of activated clay had a significant effect on the physicochemical parameters of OMW, with an increase in pH from 4.88 to 6.14 and a decrease in organic matter [58% chemical oxygen demand (COD) and 66% phenolic compound]. In addition, the use of treated OMW in irrigation fields had a significant effect on the germination of Lepidium sativum seeds and the growth of Vicia faba plants. From this study, we can conclude that adsorption onto activated clay is an effective method to remove residual organic from OMW and that this method could be used as a suitable alternative for the preservation of water resources in semiarid regions. Graphical Abstract