Aerobic and anaerobic biotreatment of olive oil mill waste water. (c2006)

Abstract

Olive oil Mill Wastewater (OMW) or Zibar is one of the two by-products obtained during olive oil extraction. OMW represents a serious environmental pollution problem especially for underground and surface water. Aerobic and anaerobic OMW biotreatment processes were developed and improved at the LAU Biotechnology Labs and showed great success. A bacterial mixture of ten strains (Aquaspirillum dispar, Bacillus cereus/thuringiensis, Brevibacterium otitidis, Klebsiella pneumoniae, Proteus penneri/ vulgaris, Pseudomonas fluorescence biotype F, Pseudomonas marginalis, Pseudomonas mendonica, Pseudomonas sp. , and Pseudomonas viridilivida) and five yeast cultures (Candida boidini, Candida memodendra, Candida mogii, Pichia haplophia, and Sacharomyces ludwigii) were isolated from OMW, purified and reused in OMW aerobic biotreatment. After four days of aerobic small lab scale fermentation, a 68.9 % of BOD and a 67.8 % of COD reduction was achieved. A 69.3 % of BOD and a 68.4 % COD reduction was obtained during eight days of intermediate scale biotreatment. After fourteen days of pilot scale biotreatment, a 69.1 % reduction was recorded in BOD values and a 68.2 % reduction in COD values. Finally, a 71.0 % BOD and a 63.9 % COD reduction was observed after thirty-one days of industrial scale biotreatment. Anaerobic OMW experimental lab scale biotreatment using omasomal juice as experimental inoculum culture achieved a reduction of 67.8 % BOD and 66.6 % COD with 6.1 I of methane production after six weeks of incubation Combining aerobic OMW biotreatment with anaerobic treatment, 74.3 % of BOD and 73.2 % of COD reduction were reached. Above mentioned OMW biotreatment processes, developed at LAD Biotechnology Labs, achieved acceptable BOD and COD reduction rates, are low cost and suitable to be applied in small rural olive mills in Lebanon and in the Middle East.