Abstract
Olive mill wastewater (OMW) constitutes a major industrial and environmental problem. The uncontrolled discharging of OMW into the wastewater treatment plant has long been considered as a matter of treatment, minimization, and prevention due to the environmental effects induced by their disposal. Most of OMW treatment methods aim at organic matter destruction, hence the reduction of chemical oxygen demand (COD). In this study, bio-treatment of OMW, by a selected actinomycetes consortium in the attached growth manner, was utilized for degrading complex organic compounds. The progress on this problem is made by reducing the COD, which represents a major OMW pollutant. In this regard, Garada Wastewater Treatment Plant was firstly evaluated using principal component analysis (PCA). Secondly, microcosms study was undertaken for the reduction of organic load in raw wastewater by testing five actinomycetes isolates (19S, 32S, 56S, 62S, and 66S) for their abilities on the degradation of organics. PCA indicated that Salinity total dissolved solids, and COD of the wastewater had the greatest effect on the treatment process. The isolate Micromonospora sp. 19S showed the remarkable capability to degrade the organics in wastewater, reaching up to 80% at the end of 5 d in the batch experiment, whereas isolate Micromonospora sp. 56S achieved 70% reduction in organic load for the same duration time. Finally, the actinomycete isolates were attached to two types of carrier media in microcosm and left for 5 h to initiate biofilm formation.