[Treatment of olive mill wastewater by a process combining an intensive treatment (Jet-Loop reactor) followed by an extensive treatment (stabilization ponds)]. / Traitement des effluents d'huileries par un procédé combinant un traitement intensif (Jet-Loop reactor) suivi d'un traitement extensif (bassins de stabilisation).

Olive oil mill wastewater (OMW) is generally recognized as an environmentally troublesome by-product of the olive oil industry as its disposal without any treatment is known to cause serious environmental problems. However, this effluent has a high fertilizing power and constitutes, with urban wastewater, an important low-cost source. Biological treatment of OMW, with a process combining an aerobic reactor, 'Jet-Loop', and waste stabilization ponds, was investigated for possible agricultural reuse. The focus of the present study was to evaluate the contribution and the complementarity of the two systems in the total OMW treatment. Bio-treatment was performed using a 100-litre Jet-Loop reactor working volume achieving a chemical oxygen demand (COD) and phenolic compounds maximum removal rate of 72% and 68%, respectively, at a hydraulic retention time of 10 days. Co-treatment of OMW and domestic wastewater in waste stabilization ponds, with a hydraulic retention time of 22 days, reached a global removal rate of 66% for COD while no trace of phenolic compounds was detected on this level during the entire treatment period. Dynamics of faecal coliforms in stabilization ponds showed a total removal rate of 99.9% (3 logarithmic units (Log.U)). Preliminary results of agronomic tests on the ray-grass have evaluated the fertilizing effect of the final effluent resulting from the co-treatment.

Co-treatment of olive-mill and urban wastewaters by experimental stabilization ponds.

Olive oil mill wastewater (OMW) constitutes a source of environmental problems in Morocco due to its significantly high organic load, its phytotoxic properties and its relatively low biodegradability. An effective option for its disposal is its agricultural use after co-treatment with urban wastewater (UWW). The main objective of this investigation was to evaluate the potential of this co-treatment, using experimental waste stabilization ponds, in removing OMW phytotoxicity. We examined the influence of the organic load, at the entry of the treatment system, on the evolution of some physicochemical (chemical oxygen demand and polyphenols) and microbiological (fecal coliforms and fecal streptococci) parameters. The results showed a removal of the organic, phenolic and microbial load throughout the treatment which differed from one system to another according to the OMW load applied to each system. The results concerning the germination assays of Zea mays and Solanum lycopersicum suggested that the co-treatment of OMW with UWW would decrease the phytotoxicity of this waste.

Application of lime and calcium hypochlorite in the dephenolisation and discolouration of olive mill wastewater.

The application of hypochlorite for the removal of soluble COD, phenolic and polyphenolic like compounds, and other organic compounds responsible for the olive mill wastewater (OOWW) colour has been experimentally studied. After the OOWW filtration on a sand column, the effluent was subjected to a fast liming under optimal conditions. Lime application reduced polyphenols, COD and SS contents to half of their initial values but an important blackening of the treated OOWW was observed, especially when adding high concentrations of lime (10% (W/V) and 15% (W/V)). A second stage of treatment was applied using calcium hypochlorite. In this stage, removal of the studied compounds reached as much as 95% at higher concentrations, and particularly the colouring of OOWW which is generally difficult to eliminate was greatly reduced. The OOWW hypochloration acted through coagulation-flocculation and a rapid oxidation of the organic matter proceeded from the first 5min. The kinetic study of the degradation of the waste polluting compounds from liming showed that Ca(ClO)(2) reacts similarly in the elimination of organic compounds, polyphenols, SS and colouration. The analysis of the organochloride compounds generated by the reaction between hypochlorite and the organic compounds showed that DDD, DDT and the heptachlor contents exceeded the values recommended by the International and European drinking water standards.

[Impact of olive oil wastewater on the physicochemical and biological quality of groundwater in the Haouz plain, south of Marrakesh (Morocco)]. / Impact des effluents des huileries d'olive sur la qualité physico-chimique et biologique des eaux souterraines dans la plaine du Haouz au sud de Marrakech (Maroc).

Olive Oil Waste Water (OOWW) is acidic water known for its antibacterial and phytotoxic effects. In Morocco, these effluents are generally drained into the surrounding environment without any treatment or are collected and retained in large evaporation basins, which can constitute a source of potential pollution of groundwater. The analysis of water from 14 wells, in an agricultural zone, where there are four storage basins of OOWW coming from various types of oil mills, showed that their physicochemical and biological quality is largely influenced by the presence of these basins. Indeed, high values of COD (400 mg O2 L(-1)), polyphenols (180 mg l(-1)) and electrical conductivity (1.89 mS cm-') were recorded in P5 water. This well is located only 5 m from a storage basin of OOWW coming from the H4 oil mill which rejects OOWW charged with organic matter (more than 290 g of O2 L(-1) of COD, on average). However, the settlement of a basin, dug close to a modern oil mill (H3), which produces large OOWW volumes but is loaded with low organic pollutant concentration (100 g of O2L(-1) of COD), reduced notably the effect of the OOWW infiltration on groundwater. This resulted in the improvement of the groundwater physicochemical quality near this basin (P7 and P8); the organic matter contents expressed by COD vary from 26.7 mg l(-1) to 30 mg l(-1) and the polyphenol contents are on average between 41 mg l(-1) and 47.6 mg l(-1). The analysis of the total well water fauna showed a great taxonomic richness with variations in time and space. The biodiversity decreases in groundwater polluted by the oil mill waste and the underground fauna disappears completely if the degree of contamination of groundwater is high.