Taher Mechichi

Bio: Taher Mechichi is an academic researcher. The author has contributed to research in topics: Soil horizon & Soil water. The author has an hindex of 2, co-authored 2 publications receiving 52 citations.

Changes in Soil Macronutrients after a Long-Term Application of Olive Mill Wastewater

Abstract: The land spreading of olive mill wastewater (OMW) derived from olive oil production can represent a suitable option to enrich and maintain agriculture soils under south Mediterranean climates. Therefore, OMW spreading field may represent a low cost contribution to crop fertilization and soil amendment. The main objective of this study was to investigate the long-term effects of raw OMW application on soil macronutrients and phenolic compounds dynamics. The results showed that regular application of three doses: 50, 100 and 200 m3·ha-1 of OMW for nine successive years increased the soil electrical conductivity significantly (p ≤ 0.05%) with the increase of OMW rates at the depth 0 - 20 cm. The pH variations were not detected after ten months of the spreading date. Furthermore, soil sodium adsorption ratio (SAR) and exchangeable sodium percentage (ESP) values were substantially affected by OMW salinity. The soil organic matter (SOM) increased from 0.068% observed for the control sample to 0.2%, 0.34% and 0.48%, respectively, with the increase of OMW rate in the top layer (0 - 20 cm). The potassium, phosphorus and nitrogen increased gradually with the OMW application dose. The Ca2+ contents on soil decreased with the spreading of OMW rate, as referred to control. In addition, the phenolic compounds variations were not proportional to doses applied and its levels remained high as compared with the control essentially on top layers (0 - 40 cm). This practice should be beneficial to organic farming and is an alternative solution to direct spreading of raw OMW on soil.

Effects of Olive Mill Wastewater on Soil Nutrients Availability.

Abstract: Olive mill wastewater (OMW) is one of complex wastewater generated by the olive oil extraction process. It is characterized by high values of COD, BOD and phytotoxic levels of polyphenols, but also by a high amount of organic compounds and plant mineral nutrients. Therefore, OMW field spreading may represent a low cost contribution to soil amendment. Olive mill wastewater (O MW) spraying effects onto soil physico-chemicals characteristics were investigated. Three OMW doses 50, 100 and 200 m 3 ha -1 year -1 were applied for ten successive years on sandy soil. The findings showed that t he pH of the soil, electrical conductivity and organic matter, total nitrogen, phosphorus, sodium, and potassium s oil contents increased with increased OMW supply. While, no variations were recorded in calcium and magnesium on soil contents.

Greywater Treatment with Two Planted Vertical Constructed Wetlands in Series: A Pilot Study

Abstract: Two pilot scales of planted vertical flow-built wetlands in series treating greywater were accomplished and evaluated in the Tunisian Deaf Help Association (TDHA). The pilot plant's two beds were planted with Phragmites australis and given a continuous daily flow of 640 L with nominal operating retention duration of 1.25 days. The total suspended solids (TSS) mean removal efficiency in the first bed was 86.2 ± 10%, and both beds received the same treatment performance for chemical oxygen demand (COD) and biochemical oxygen demand after five days (BOD5). The overall completed removal rates for TSS, COD, and BOD5 were 94 ±13, 86 ± 5.7, and 93 ± 7%, respectively. Relating to ammonium, the overall achieved removal rate was 71.4 ± 19.1% in both beds, however, the removal rate was around 60 ± 9.11% when based on a single bed. In terms of phosphorous, the second bed enhanced its removal twice, resulting in a reduction of 52%. Regarding the bacterial abatement in each planted bed, Escherichia coli clearance ranged from 1.24 to 2.40 logs, respectively, and the total bacteria population yielded an average of 1.65 log units, equivalent to an efficiency of 46.67%. These results were complemented by polymerase chain reaction-denaturing gradient gel electrophoresis, which showed an overall of biomass reduction of 47 ± 8% with one bed, and of 89 ± 7% with both beds. This article is protected by copyright. All rights reserved

Evaluation of enrichment with antioxidants from olive oil mill wastes in hydrophilic model system

Abstract: Agro food industry generates significant amounts of by‐products, as olive oil mill waste waters (OMWW), which could be valorize for their extraordinary content of bioactive compounds. The aim of this work was to evaluate the antioxidant stability of a hydrophilic model system with the possibility to create a functional beverage. The study was divided into different steps: extraction of phenolic compounds (PCs) from olive oil waste waters, formulation of enriched water fortified with phenolic extract (PE) (50 and 100 mg tyrosol/L), and evaluation of its physicochemical and antioxidant parameters during storage. Ultra‐high performance liquid chromatography was used for the evaluation of single phenols present in the extract, and the highest content was observed for tyrosol (12.9 g/L). The results of this study showed that antioxidant capacity measured by diphenyl‐1‐picrylhydrazyl and ABTS assays is relatively stable during the storage in the samples enriched with lower concentration of PE (50 mg tyrosol/L). PRACTICAL APPLICATIONS: The olive oil industry generates huge quantities of waste, with shown significant amounts of by‐products that are discarded and can be a serious environmental problem. This food by‐products are an extraordinary source of bioactive compounds, which can be recovered in order to produce valuable metabolites via chemical and biotechnological processes. The study demonstrated that the OMWW have a high concentration of PC and antioxidant activity. These antioxidant compounds can be used in the food industry for the production of beverages and/or enriched foods.