Explore the vast range of titles available.

Membrane bioreactor (MBR) has been proven to be an efficient technology capable of treating various industrial effluents. However, the evaluation of its performances in the case of olive mill wastewater (OMW) over a conventional activated sludge (CAS) have not been determined yet. The present study aims to compare OMW treatment in two laboratory scale pilots: an external ceramic MBR and CAS starting with an acclimation step in both reactors by raising OMW concentration progressively. After the acclimation step, the reactors received OMW at 2 gCOD/L with respect to an organic loading rate of 0.2 and 0.3 kgCOD/kgMLVSS/d for MBR and CAS, respectively. Biomass acclimation occurred successfully in both systems; however, the MBR tolerated more OMW toxicity than CAS as the MBR always maintained an effluent with a better quality. At a stable state, a higher reduction of 95% chemical oxygen demand (COD) was obtained with MBR compared to CAS (86%), but both succeeded in polyphenols removal (80%). Moreover, a higher MLSS elimination from the MBR treated water (97%) was measured against 88% for CAS. Therefore, CAS was suitable for OMW treatment and MBR could be proposed as an alternative to CAS when a better quality of treated water is required.

This study aims to investigate the feasibility of treating olive mill waste water (OMWW) by activated sludge pilot (AS) after its high dilution (1%) by urban waste water (UWW) and to study the effect of polyphenol compounds on the biomass during the treatment. Specific oxygen uptake rate (SOUR), mixed liquor volatile suspended solids (MLVSS), chemical oxygen demand (COD) and total polyphenols, were followed up over 100 days. In spite of the polyphenols' high concentration (up to 128 mg·L−1), successful biomass growth of 7.12 g MLVSS.L −1 and activity were achieved. Most of the bacteria (Pseudomonas sp., Klebsiella oxytoca, Citrobacter fereundii, Escherichia coli and Staphylococcus sp.) and fungi (Trichoderma sp., Rhizopus sp., Aspergillus niger, Penicillium sp., Fusarium sp., Alternaria) identified in the aerobic basin during the stabilization stage were known to be resistant to OMWW and showed effective adaptation of the biomass to polyphenols in high concentration. COD and polyphenols were highly eliminated (90%, 92% respectively). The sludge volume index in the pilot settling tank was almost constant at around 120 mL.g −1. This suggests the possibility of managing OMWW by simple injection at a given percentage in already functioning conventional AS treating UWW.

As a result of the early domestication and extensive cultivation of the olive tree throughout the Mediterranean Basin, the wild-looking forms of olive (oleasters) presently observed constitute a complex, potentially ranging from wild to feral forms. Allozyme variation was analysed at 10 loci in 31 large and 44 small oleaster populations distributed in various habitats of the Mediterranean Basin and in two populations of the wild subspecies Olea europaea subsp (ssp) guanchica, endemic to the Canary islands and closely related to oleasters. At eight polymorphic loci, 25 alleles were identified. Genetic evidence that nondomesticated oleasters still survive locally was provided by the occurrence of four and one alleles shared exclusively by the eight western and two eastern oleaster populations, respectively, which were collected in forests potentially containing genuinely wild forms according to environmental, historical and demographic criteria. As reported previously from cytoplasmic and RAPDs analysis, substantial genetic differentiation was observed between the eastern oleaster populations genetically close to most olive clones cultivated in the Mediterranean Basin, and the western populations that are related to the wild Canarian populations. In addition, the occurrence of significantly lower heterozygosity in cultivated olive than in oleasters, whatever their origin, suggests that intensive selection involving inbreeding has taken place under cultivation to obtain particular characteristics in the olive cultivars.

Currently, research focuses on the application of newer biocoagulant products in wastewater treatment. In this study, the performance of cactus juice to clarify Olive Mill Wastewater (OMW) was investigated by using Jar-test experimentation and assessed by physicochemical analysis of the obtained supernatant: turbidity, total suspended solids (TSS), (λ465; λ395) absorbance, polyphenols (pp), chemical oxygen demand (COD) and Fourier-Transform-Infrared spectroscopy (FTIR) on lyophilized sludge. A series of experiments were conducted to estimate the influence of various experimental parameters, such as the amounts of biocoagulants used, time, stirring speed, and pH. The study showed the optimal coagulation conditions were as follows: sample pH10; cactus juice dose, 10% (v/v); rapid mixing time, 30 s at a speed of 150 rp/min. Under these conditions, the overall removals of 74% for COD, 93% for turbidity and 51% for polyphenols were achieved. As referring to the FTIR analysis, the cactus juice of Opuntia spp. operates predominantly through an adsorption interparticle bridging coagulation mechanism. These results are encouraging in the context of developing a low-cost technology and eco-friendly approach for the effective management of OMW.

The purpose of this work is to investigate experimentally the effect of drying temperature and thickness on the drying curve of a conductive drying of washing phosphate sludge samples. Two mathematical models based on Fourier's Fick diffusion law and heat transfer equation were developed to simulate the drying. The first model neglected the shrinking effect while the second one took it into account. The findings showed that drying temperature increase and/or the samples thickness decrease enhance the drying rate. Furthermore, the drying curves showed the presence of the three classical drying periods corresponding to: adaptation, constant drying rate and falling drying rate periods. Based on the analytical solutions and according to the statistical criteria (R 2 , RMSE), it was concluded that the model incorporating the shrinking effect is the best model to describe the drying behavior of washing phosphate sludge in all tested conductive drying conditions.

Early domestication and extensive cultivation have meant that staple Mediterranean fruit crops such as olives, grapes and dates exist in wild-looking forms that are secondary derivatives produced by sexual reproduction among cultivated plants (cultivars), which were initially propagated vegetatively. By using genetic markers associated with characters that render plants unsuitable for domestication, we show here that genuinely wild olive trees, which cannot be distinguished morphologically from feral forms, still survive in a few Mediterranean forests. These wild stocks are genetically distinct and more variable than either the crop strains or their derived feral forms, a finding that has important implications for the conservation of these ancient lineages.

A total of 105 yeast strains were isolated from Moroccan olive oil production plants and evaluated for their ability to grow in olive oil mill wastewaters (OMW). The 9 isolates that grew best on OMW were selected for further study to evaluate their effect on removal of organic pollutants and OMW phytotoxicity (barley seed germination test). The results showed that at least four yeast isolates effectively lowered the toxicity of this effluent in addition to providing very useful materials in terms of both yeast biomass (6 g/l DW) and an irrigation fluid. This group of yeast isolates significantly reduced the concentration of total phenols (44% removal) and Chemical Oxygen Demand, COD (63% removal). The best germination rate of 80% for undiluted OMW was obtained for strain Candida holstii that also increased the pH from 4.76 to 6.75. Principal component analysis of the results obtained for the best yeast strains confirmed the importance of COD and total phenol reduction along with increase of organic nitrogen and final pH for the improvement of germination rates and phytotoxic reduction. This study has highlighted the potential of indigenous yeasts in detoxification of olive mill wastewaters.

In olive tree (Olea europaea L.), 12 varieties (or cultivars) representing the main domesticated material used in Morocco and 19 olive cultivars used extensively in five countries of the western Mediterranean Basin, were analysed using inter-simple sequences repeat (ISSR) markers which had never been used previously for extensive discrimination of cultivars. Four selected primers produced a total of 26 polymorphic reproducible amplification fragments. Combinations of these ISSR markers allowed to identify 25 of the 31 cultivars. Two additional combinations were distinguished, each corresponding to three Moroccan cultivars or local varieties. Evidence of a multiclonal composition in the widely cultivated variety ‘Picholine marocaine’ was obtained by the identification of three genotypes within the four morphologically distinct clones analysed in the variety. In the UPGMA phenogram based on the proportion of shared ISSR fragments, five groups of cultivars were distinguished at the 40% critical value of similarity. Four of the groups contained varieties from various geographic origins, as the consequence of successive human migrations which favoured olive dispersion throughout the Mediterranean Basin. However, the fifth group gathered together 9 of the 12 Moroccan cultivars and very few cultivated clones from Greece and Spain. The results suggest that most of the Moroccan cultivars are closely related and likely originated from local domestication.

The aim of the present work is the assessment of metal toxicity in runoff, in their contaminated soils and in the groundwater sampled from two mining areas in the region of Marrakech using a microbial bioassay MetPLATE[trade mark sign]. This bioassay is based on the specific inhibition of the β-galactosidase enzyme of a mutant strain of Escherichia coli, by the metallic pollutants. The stream waters from all sampling stations in the two mines were all very toxic and displayed percent enzyme inhibition exceeding 87% except SWA₄ and SWB₁ stations in mine C. Their high concentrations of copper (Cu) and zinc (Zn) confirm the acute toxicity shown by MetPLATE. The pH of stream waters from mine B and C varied between 2.1 and 6.2 and was probably responsible for metal mobilization, suggesting a problem of acid mine drainage in these mining areas. The bioassay MetPLATE[trade mark sign] was also applied to mine tailings and to soils contaminated by the acidic waters. The results show that the high toxicity of these soils and tailings was mainly due to the relatively concentration of soluble Zn and Cu. The use of MetPLATE[trade mark sign] in groundwater toxicity testing shows that, most of the samples exhibited low metal toxicity (2.7-45.5% inhibition) except GW3 of the mine B (95.3% inhibition during the wet season and 82.9% inhibition during the dry season). This high toxicity is attributed to the higher than usual concentrations of Cu (189 μg Cu l-¹) and Zn (1505 μg Zn l-¹). These results show the potential risk of the contamination of different ecosystems situated to the vicinity of these two metalliferous sites. The general trend observed was an increase in metal toxicity measured by the MetPLATE with increasing total and mobile metal concentrations in the studied matrices. Therefore, the MetPLATE bioassay is a reliable and fast bioassay to estimate the metals toxicity in the aquatic and solids samples.

Cyanobacteria blooms occur frequently in freshwaters around the world. Some can produce and release toxic compounds called cyanotoxins, which represent a danger to both the environment and human health. Microcystin-LR (MC-LR) is the most toxic variant reported all over the world. Conventional water treatment methods are expensive and require specialized personnel and equipment. Recently, a multi-soil-layering (MSL) system, a natural and low-cost technology, has been introduced as an attractive cost-effective, and environmentally friendly technology that is likely to be an alternative to conventional wastewater treatment methods. This study aims to evaluate, for the first time, the efficiency of MSL eco-technology to remove MC-LR on a laboratory scale using local materials. To this end, an MSL pilot plant was designed to treat distilled water contaminated with MC-LR. The pilot was composed of an alternation of permeable layers (pozzolan) and soil mixture layers (local sandy soil, sawdust, charcoal, and metallic iron on a dry weight ratio of 70, 10, 10, and 10%, respectively) arranged in a brick-layer-like pattern. MSL pilot was continuously fed with synthetic water containing distilled water contaminated with increasing concentrations of MC-LR (0.18–10 µg/L) at a hydraulic loading rate (HLR) of 200 L m−2 day−1. The early results showed MC-LR removal of above 99%. Based on these preliminary results, the multi-soil-layering eco-technology could be considered as a promising solution to treat water contaminated by MC-LR in order to produce quality water for irrigation or recreational activities.