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Abstract: Olive mill wastewater (OMW) was treated by photocatalysis using TiO2 under UV irradiation on the laboratory scale. The chemical oxygen demand, the coloration at 330nm, and the level of phenols all showed decreases which, after a 24-h treatment, reached 22%, 57% and 94%, respectively. The differences between these three values indicate the persistence of colourless, non-phenolic compounds. Application of the novel Fictitious Atomic-Group Separation method showed an increase in carbon oxidation state and confirmed that the attack primarily concerns, aromatic moieties. A fine spectroscopic study revealed the occurrence of three successive phases during the degradation process, thought to correspond to three different categories of molecules in the OMW and the presence of pectin compounds. [Copyright &y& Elsevier]

Indigenous microflora community changes during six months of co-composting of activated sewage sludge and date palm waste was investigated using two different culture approaches. In order to evaluate the co-composting process evolution for mixture A and B, growth standard media (GSM) and Compost Time Extract Agar (CTEA) are used. Enumeration for indigenous flora abundance on GSM medium shows that the colony-forming unit (CFU) total number was 100 fold higher than on CTEA. The thermophilic phase is determined at 30 day for both mixtures A and B. Nevertheless this stage is limited only at 22 and 30 days, respectively for mixture A and B on CTEA medium, which indicate a similar temperature profile at versus time of co-composting. The results suggest that the GSM medium approach can be used for monitoring the microbial cultivable presence. However, CTEA act as a natural selective medium to enumerate the indigenous functional microflora. This technique was successful in assessing the process evolution and determination of a real succession thermophilic and maturation co-composting stages.

Olive mill wastewater (OMWW) is a by-product of the olive oil extraction industry. Its dumping creates severe environmental problems in the Mediterranean countries. The phytoxicity of OMWW is due to the phenolic substances and is evaluated through a genotoxicity method. An aerobic treatment of OMWW was conducted during 45 days. Different concentrations of raw and treated OMWW were tested using the Vicia faba micronuclei test. Results showed that raw OMWW induced significant micronuclei formation at 10% of OMWW dilution. At 20% of dilution, no mitosis was recorded. The 45 days aerobic treatment OMWW showed an important decrease in the genotoxicity and also in the toxicity that was observed at 10% and 20% OMWW dilution. This could be correlated with the biodegradation of 76% of the total phenols. Indeed, qualitative analysis by high performance liquid chromatography shows the disappearance of the majority of phenolic compounds after 45 days of treatment. This study was completed by an agricultural test with V. faba plant. Data showed significant growth yield of 36.3% and 29.9% after being irrigated with 5 and 10 t/ha, respectively. These results supported the positive role of aerobic treatment on OMWW and their capacity to ameliorate the agronomic potential of these effluents.

Liquid and solid olive oil mill waste was treated by com posting in a mixture with the organic part of municipal solid waste and rock phosphate. The transformations that occurred during the process were evaluated by physical, chemical and spectroscopic analyses. After five months of com posting, the final compost presented a C/N ratio under 20, an NH4+/NO3(-)] ratio under 1 and a pH around neutral. A high level of organic matter decomposition paralleled a notable abatement of phenols and lipids. The results show the effective dissolution of mineral elements during composting. This transformation was followed by Fourier transform infrared which showed a decrease in the absorption bands of aliphatic bonds (2925 and 2855 cm(-1)) and carbonyls of carboxylic origin (1740 cm (-1)). In addition to the increase in humic substances and the improvement of germination indices, the parameters studied confirm the stability and the maturity of the composts. The absence of phytotoxicity opens the way to agricultural spreading.