Olive mill wastewater (OMWW) contains high concentrations of phenolic compounds that can induce a significant damage to the biological process of a wastewater treatment plant. In a newly macro-encapsulation procedure named the Small-Bioreactor Platform (SBP) technology as a method for a bioaugmentation treatment, we introduced autochthonous microbial cultures into 2.5 cm long microfiltration membrane capsules. In the present study, we aimed to explore the ability of the postulated technology to provide a protective environment for the microbial culture while facilitating the breakdown of phenolic compounds. This will allow a successful bioaugmentation treatment approach within domestic wastewater treatment plants in order to protect the natural biomass of the wastewater treatment plants from the OMWW`s antimicrobial agents. Our results present the ability of encapsulated autochthonous bacterial cultures to biodegrade phenols as sole contaminants or in a blend of phenolic compounds within minimal salts medium and within raw OMWW. The biodegradation of four phenols types (phenol, tannic, gallic and caffeic acids) as a sole carbon source, showed a complete breakdown within 48 h for tannic and caffeic acids while gallic acid and phenol was consumed within 24 h. When the biodegradation rate of a high concentration phenols mixture (3000 mg/l) was tested, the encapsulated biomass succeeded to reduce the phenolic blend concentration to approximate 500 mg/L within 24 h. In addition, polyphenols compounds concentration in fresh OMWW was effectively reduced in the presence of the encapsulated cultures. The efficiency of the new bioaugmentation approach in improving the biological treatment of wastewaters is discussed.
