Chemical characterization and adsorption of oil mill wastewater on Moroccan clay in order to be used in the agricultural field

Younes Dehmani; Abdelaziz Ed-Dra; Omar Zennouhi; Aziz Bouymajane; Fouzia Rhazi Filali; Laila Nassiri; Sadik Abouarnadasse

doi:10.1016/j.heliyon.2020.e03164

Chemical characterization and adsorption of oil mill wastewater on Moroccan clay in order to be used in the agricultural field

Heliyon. 2020 Jan 27;6(1):e03164. doi: 10.1016/j.heliyon.2020.e03164. eCollection 2020 Jan.

Authors

Younes Dehmani¹, Abdelaziz Ed-Dra², Omar Zennouhi³, Aziz Bouymajane², Fouzia Rhazi Filali², Laila Nassiri³, Sadik Abouarnadasse¹

Affiliations

¹ Laboratory of Chemistry/Biology Applied to the Environment, Faculty of Sciences, Moulay Ismaïl University, BP 11201-Zitoune, Meknes, 50070, Morocco.
² Team of Microbiology and Health, Laboratory of Chemistry-Biology Applied to the Environment, Moulay Ismail University Faculty of Science, BP 11201 Zitoune, Meknes, Morocco.
³ Soil and Environment Microbiology Unit, Faculty of Science, Moulay Ismail University, BP 11201 Zitoune, Meknes, Morocco.

Abstract

Oil mill wastewater (OMW) is the main liquid discharge from oil mills, it is considered as a dangerous pollutant due to its toxic chemical compounds which are unloaded directly in the environment without any treatment. The aims of this study were to evaluate the effectiveness of OMW adsorption on clay as a good method for the elimination of toxic chemical compounds and to study the application of treated OMW as an irrigation source in agricultural field. For this, Clay was collected from the city of Agourai (Meknes region, Morocco) and characterized by X-ray diffraction, X-ray fluorescence spectrometry, BET and FTIR analysis. Moreover, the treated OMW was analyzed using UHPLC-ESI-MS and the determination of total phenolic content (TPC) was also performed. However, the application of the treated OMW in agricultural field was performed by the determination of its effect on the germination of Lepidium sativum seeds (in vitro) and as a source of irrigation of Vicia faba plants (in situ). The results of this study showed that OMW had the following physicochemical characteristics: average pH of 4.88, TPC of 4.75 g/l, COD of 80 g/l, BOD5 of 18.72 g/l, conductivity of 16.05 cm-1, dry matter of 135.7 g/l and volatile matter of 58.7 g/l. The adsorption on clay had increased the pH from 4.88 to 6.14 and reduced significantly the organic matter (42% of COD and 57.4% of phenolic compounds). UHPLC-ESI-MS analysis showed the presence of a wide variety of organic compounds in OMW, with the appearance of new compounds after adsorption. Moreover, the use of treated OMW as a source of irrigation showed a significant effect on the germination of Lepidium sativum seeds and the growth of Vicia faba plants. From this study, we can conclude that the adsorption on clay is a good method for the treatment of OMW, which became non-toxic for environment and can be used as a source of irrigation in agricultural field.

Keywords: Adsorption; Agricultural science; Biological application; Chemical characterization; Environmental science; Materials science; Moroccan clay; Oil mill wastewater.