Treatment Of Olive Oil Mill Wastewater Research Articles

Exploring the potential use of chitosan derived from Hermetia illucens waste for olive oil mill wastewater treatment

Exploring the potential use of chitosan derived from Hermetia illucens waste for olive oil mill wastewater treatment

Evaluation of Biobed Bio-Mixture from Olive Oil Mill Wastewater Treatment as a Soil Organic Amendment in a Circular Economy Context

This study, based on circular economy principles and sustainable development practices, aims to present the results of soil samples analysis after their mixture with a biobed bio-mixture of straw, soil and compost, used for two consecutive years as organic bio-filter of olive oil mill wastewater. So far, exhausted bio-mixtures used in biobeds to minimize pesticide point-source contamination turned out to contain residues of pesticides, and they are considered hazardous wastes; thus, they require special treatment before their disposal. Contrariwise, saturated bio-mixtures from bio-bed systems utilized for olive mill wastewater (OMWW) treatment not only do not require any special treatment before their final disposal but also can be exploited as a soil amendment. To this end, the effects of the used bio-mixture application in three different proportions as a soil amendment on the physical and chemical properties of medium-texture soil were investigated. The application of water simulating a typical irrigation period during a growing season took place. Upon completion of the water application, soil samples were collected from two different depths of the columns and analyzed, and leachates collected from the columns were also analyzed. Soil texture, organic matter, calcium carbonate, electrical conductivity (EC), pH, total nitrogen, nitrates, nitrites, ammonium, available phosphorus, exchangeable potassium, sodium, calcium and magnesium, exchangeable sodium percentage (ESP), cation exchange capacity (CEC), available iron, manganese, copper, zinc and boron were monitored in the soil samples as indexes of potential soil amendment, and EC, pH, nitrates, potassium, sodium, calcium, magnesium, sodium adsorption ratio (SAR), total hardness, iron, manganese, copper, zinc and boron were monitored in the leachates as indexes of potential groundwater contamination.The study demonstrated the effective use of saturated bio-mixture as an organic soil amendment, while the impact of selected amendments on groundwater was the minimum.

Solar driven photocatalysis using iron and chromium doped TiO2 coupled to moving bed biofilm process for olive mill wastewater treatment

TiO2 based-photocatalysts doped with Fe and/or Cr was evaluated as pre- and post-treatment method of a moving bed biofilm reactor (MBBR) as possible solution for the treatment of real olive oil mill wastewater (OMW). Photocatalysts were synthesized by wet chemical method and their chemical-physical properties were accurately investigated through X-ray diffraction (XRD), Raman spectroscopy, UV–Vis diffuse reflectance spectroscopy (UV–Vis DRS) and specific surface area measurements. UV–Vis DRS measurements evidenced that the simultaneous doping of TiO2 lattice with Fe and Cr improves the optical absorption into the visible region leading to a narrow band gap (2.1 eV) with respect to undoped TiO2 (3.2 eV) and Fe-doped TiO2 (2.8 eV) while, Cr-doped TiO2 showed the lowest bandgap value (1.9 eV). XRD patterns and Raman spectra showed that anatase is the predominant crystalline phase for all the prepared photocatalysts and Fe and Cr ions were effectively inserted into the TiO2lattice. The TiO2 doping with Cr did not change the average crystallites size that was equivalent to that of TiO2(8 nm), whereas, for Fe- doped TiO2, it was lower than the others and equal to 6 nm. The specific surface area values of doped catalysts were higher than TiO2 and the value for Fe-Cr-codoped TiO2 resulted to be 97 m2g−1. Photocatalytic treatment of OMW was evaluated in terms of total polyphenols (TPHs), Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD5) and biodegradability (as BOD5/COD ratio) in 3 h of treatment under simulated solar light irradiation. Fe-doped TiO2 showed the highest TPHs removal for both un-treated and biologically treated OMW. When H2O2 was added (optimum dosage 0.5 gL-1), Fe-Cr-TiO2 resulted in the best photocatalytic performance with TPHs removal as high as 97% and increased biodegradability (0.22 to 0.33), making the effluent suitable for the subsequent biological process. When photocatalytic process was investigated as post-treatment of OMW, Fe-TiO2 showed the best activity and the addition of 0.5 g L-1 of H2O2 was sufficient to make the effluent in compliance with Italian regulation for effluent disposal into surface water.

Sustainable olive-oil mill wastewater treatment by distillation using a parabolic trough solar collector

The olive oil industry, although among the most important sectors in the Mediterranean basin, causes huge environmental problems due to the discharge of polluting wastewater. The treatment of olive-oil mill wastewater is therefore at the crossroads of many concerns and is a major challenge for sustainable development. This study focuses on the exploitation of a parabolic trough solar collector as a clean source of energy for sustainable olive-oil mill wastewater treatment. A conical coil heat exchanger immersed in an olive-oil mill wastewater distillation reservoir is coupled with a parabolic trough solar collector. The productivity, environmental impact, and profitability of the proposed prototype are experimentally evaluated. A comparative study and a Physico-chemical characterization of filtered and unfiltered olive-oil mill wastewater are conducted to assess their potential reuse. A simulation using a spray-type falling film evaporation approach is realized to achieve numerical optimization. The obtained results show that the use of a parabolic trough solar collector allows more heat gain to be transferred into the distiller, enhancing system productivity, and decreasing temperature fluctuation compared to the traditional solar distiller. A significant reduction of 95 % to 97 % of phenolic compounds is observed for the distillate. The overall analysis reveals that the 26.6 m2 parabolic trough solar collector aperture area has generated 19 MWh of thermal energy throughout the olive oil post-production phase, which led to the avoidance of about 12,660 kg (eq) of CO2 emissions, while the Levelized cost of heat was 0.3 $/kWhth.

Application of Five Different Chlorella sp. Microalgal Strains for the Treatment of Vegetation Waters Derived from Unconventional Oil Extractions Enriched with Citrus Byproducts

The Mediterranean diet has, among its cornerstones, the use of olive oil for its nutraceutical and organoleptic properties. Despite the numerous merits, olive-oil mill wastewater (OMWW), which is generated by the olive-oil extraction process, is one of the most serious environmental pollutants in the Mediterranean countries. The polluting potential of OMWW is due to its high content of tannins, polyphenols, polyalcohols, pectins and lipids. In order to close the recovery cycle of a fortified citrus olive oils previously developed, we tested the ability of five microalgae of the Chlorella group (SEC_LI_ChL_1, CL_Sc, CL_Ch, FB and Idr) in lowering the percentage of total phenolic compounds in vegetation water. This was obtained with three different extraction processes (conventional, and lemon and orange peels) at three concentrations each (10%, 25% and 50%). The results showed that strains Idr, FB and CL_Sc from the Lake Massaciuccoli can tolerate vegetation water from conventional and lemon peel extractions up to 25%; these strains can also reduce the phenolic compounds within the tests. The application of microalgae for OMWW treatment represents an interesting opportunity as well as an eco-friendly low-cost solution to be developed within companies as a full-scale approach, which could be applied to obtain a fortified microalgal biomass to be employed in nutraceutical fields.

Optimization of preparation conditions of a novel low-cost natural bio-sorbent from olive pomace and column adsorption processes on the removal of phenolic compounds from olive oil mill wastewater.

Olive oil mill wastewater (OMWW) poses an undeniable environmental problem due to its high organic loads and phenolic compound (PC) content. This study determined the optimal conditions for preparing a new bio-sorbent from olive pomace (OP) and the adsorptive treatment of OMWW by this bio-sorbent. The activation reaction was performed with hydrogen peroxide. The results of the combination effect optimization of the three preparation variables, the activation temperature (°C) X1, the activation time (min) X2, and the impregnation ratio X3, are presented by the response surface methodology (RSM). The maximum adsorption capacity was obtained at an activation time of 240 min, a temperature of 80 °C, and a ratio equal to 6.2:1. The bio-sorbent was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffractometer (XRD). The adsorption process performance of this bio-sorbent was examined in batch (phenol solution) and fixed-bed columns (real effluent of OMWW). An adsorption capacity of 789.28 mg g-1 and 643.92 mg g-1 has been achieved for 4000 mg L-1 concentration of PCs, respectively, for batch and fixed-bed column essays. The adsorption isotherm and kinetics were consistent with the Langmuir and pseudo-second-order models. Therefore, the Thomas model best fits the fixed-bed column experimental data. The bio-sorbent gave a high desorption percentage of PCs, which was above 60% using HCl (0.1M).

Olive oil mill wastewater treatment by a combined process of freezing, sweating and thawing

Olive oil mill wastewater treatment by a combined process of freezing, sweating and thawing

Fe3+- IDS as a new green catalyst for water treatment by photo-Fenton process at neutral pH

In this work, a new green and fully biodegradable (96% after 28 days) catalyst, Fe3+-iminodisuccinate complex (Fe-IDS), was prepared, characterized and applied in Fenton processes (dark and photo-Fenton) for water treatment, using phenol as model organic pollutant. Experiments were performed both in dark and under solar/UV-C radiation to evaluate the effect of the light source and [H2O2] (fixed at 5.3 mM)/[Fe-IDS] ratio on the catalytic degradation of phenol (50 mg L−1). Subsequently, photo-Fenton IDS supported process was compared to other advanced oxidation processes (AOPs) (namely, conventional Fenton at pH 3 and H2O2 photolysis, under solar and UV-C irradiation, respectively). The best results (54% and 49% COD removals for solar and UV-C based processes, respectively) were obtained using a [H2O2]/[Fe-IDS] molar ratio of 250 (R250), corresponding to 0.021 mM of Fe-IDS followed by R500 (0.01 mM of Fe-IDS) and R150 (0.035 mM of Fe-IDS). Process efficiency was in the order solar/Fe-IDS/H2O2 >UV-C/Fe-IDS/H2O2 >Fe-IDS/H2O2 (k = −0.0114, −0.0073 and −0.0018 min−1 respectively) for R250. A complete removal of phenol in terms of COD was obtained for solar/Fe-IDS/H2O2 and UV-C/Fe-IDS/H2O2. Furthermore, the application of Fe-IDS complex for real industrial (olive oil mill) wastewater treatment was also investigated (initial COD in diluted sample 2.4 g L−1). At constant H2O2 concentration (58.82mM), the best performance in terms of COD removal (55%, k = 0.0031 min−1) and biodegradability (BOD5/COD increased from 0.16 to 0.45) was obtained for the condition R150 (0.37 mM of Fe-IDS). Fe-IDS allows to overcome the main limitation (acidic pH) of conventional (photo)Fenton process, making the IDS supported (photo)Fenton an attractive option for water and wastewater treatment in a wide pH range.

Effectiveness assessment of olive mill wastewater treatment by combined process: Natural flotation and anaerobic‐aerobic biodegradation

AbstractThe present work intends to study the treatment of olive oil mill wastewater (OMW) by natural flotation followed by anaerobic‐aerobic biodegradation, without dilution. After natural flotation, turbidity, chemical oxygen demand (COD) and polyphenol decreased by 37.7%, 3.7% and 3.3%, respectively. Whereas, anaerobic treatment removed 23.9% of nitrate, 29.1% of turbidity and 16.2% of polyphenol. However, intermittent aeration treatment showed the reduction of nitrate, turbidity and ammonium by 90%, 26.5% and 65.1%, respectively. In general, the combined natural flotation and anaerobic‐aerobic treatment of OMW, without dilution, have led to reduced turbidity, COD, polyphenol, nitrate, ammonium and phosphorus by 67.5%, 29.1%, 25.2%, 93.9%, 77.1% and 81.8%, respectively. The germination index of the treated OMW was 69% after 30% of dilution. Finally, the proposed treatment process could be used in small and medium‐sized industries as a simple, economical and effective method. Also, the produced water could be reused for irrigation.

Study of kinetic models of olive oil mill wastewater treatment using electrocoagulation process

Study of kinetic models of olive oil mill wastewater treatment using electrocoagulation process

Combination of physicochemical operations and algal culture as a new bioprocess for olive mill wastewater treatment

This work presents a new bioprocess design which allows a substantial reduction of organic and inhibitory compounds and a better quality of the final treated water. The process involves a physicochemical (primary) and a biological (microalgae) treatment, which were tested separately with lab equipment, for olive oil mill wastewater (OMW). Primary treatment of OMW involved flocculation-sedimentation by Flocudex CS-51 and microfiltration using a 0.2 μm membrane. Secondary treatment consisted of Scenedesmus obliquus culture in different OMW dilutions in ultrapure water as culture media: 5, 10, 25, 50, 75 and 100%. Experiments were performed on a laboratory scale in stirred batch tank reactors. The common operating conditions were: pH = 7, temperature = 25 °C, agitation rate = 3.33 Hz, aeration rate = 0.5 min−1 and illumination intensity = 359 μE m−2 s−1. High global removal levels were achieved after primary treatment for chemical oxygen demand (92.6%), total phenolic compounds (98.9%), total organic carbon (75.9%), total nitrogen (63.5%) and inorganic carbon (55.3%). Similar results were obtained for the main OMW constituents after secondary treatment with final harvested biomass rich in energetic compounds, where the highest values of carbohydrates (72.5%) in culture with 5% OMW and lipids (44.9%) in 100% OMW culture were determined.

Study of Catalysts’ Influence on Photocatalysis/Photodegradation of Olive Oil Mill Wastewater. Determination of the Optimum Working Conditions

The high production of raw olive oil mill wastewater (OMW) is a current environmental problem due to its high organic load and phenol compounds. In this work, photo-Fenton reaction as an advanced oxidation process has been chosen for OMW treatment. In this sense, different iron salts (FeCl3, Fe2(SO4)3, FeSO4·7H2O, and Fe(ClO4)3) as catalysts were used in order to compare their effects on treatment. For each catalyst, different H2O2 concentrations (2.5, 5.0, 7.5, 10.0, 15.0, 20.0, and 30.0%, w/v) as oxidizing agents were tested. The common experimental conditions were temperature 20 °C, the catalyst/H2O2 ratio = 0.03, pH = 3, and ultraviolet light. The Lagergren kinetic model, in cases of total organic carbon removal, for the best H2O2 concentration per catalyst was used. During the experiments, the water quality was determined by measuring the removal percentages on chemical oxygen demand, total carbon, total organic carbon, total nitrogen, total phenolic compounds, total iron, turbidity and electric conductivity. The best catalyst was FeCl3 and the optimum H2O2 concentration was 7.5% (w/v). At these optimal conditions, the removal percentages for chemical oxygen demand, total phenolic compounds, total carbon, total organic carbon and total nitrogen were 60.3%, 88.4%, 70.1%, 63.2% and 51.5%, respectively.

Effect of water-sludge ratio and reaction time on the hydrothermal carbonization of olive oil mill wastewater treatment: Hydrochar characterization

Hydrothermal carbonization (HTC) was used to treat olive oil mill wastewater (OOMW) by using water in the absence of any additional reagent. The reaction time and the water-sludge (W/S) ratio were varied, over a broad set of values, to study their effect on the hydrochar products.As reaction time and water-sludge ratio increased, the hydrochar yield decreased from 36% to 7%. In addition, HTC upgraded both carbon and energy contents to very high values, 76% and 36 MJ/kg respectively. Hence, the hydrochars products are good candidates for energy generation. Moreover, the hydrochars products were amorphous and had a hydrophobic oleophilic structure. Their quality and energy yield increased with the decrease in water-sludge ratio while reaction time slightly affected the hydrochar properties. Operating the process at the lowest water-sludge ratio and short reaction time leads to hydrochars with the finest characteristics but at the expense of higher cost due to evaporation rate.

Integrated process for olive oil mill wastewater treatment and its revalorization through the generation of high added value algal biomass

The two-phase continuous centrifugation process for olive oil extraction generates high amounts of olive oil mill wastewater (OMW), characterized by containing large concentrations of numerous contaminant compounds for the environment. An integral process based on physico-chemical (flocculation, photolysis and microfiltration) and microalgal growth stages was proposed for its treatment. Chemical oxygen demand (COD) removal percentages were 57.5%, 88.8% and 20.5% for flocculation, photolysis and microfiltration, respectively. The global removal percentages of organic load in the primary treatment were 96.2% for COD, 80.3% for total organic carbon (TOC) and 96.6% for total phenolic compounds (TPCs). In secondary treatment, different experiments using the microalgae Chlorella pyrenoidosa were performed on a laboratory scale in stirred batch tank reactors. The OMW concentrations in each culture medium were: 5%, 10%, 25%, 50%, 75% and 100% (v/v). The common experimental conditions were: pH = 7, temperature = 25 °C, agitation speed = 200 rpm, aeration rate = 0.5 (v/v) and illumination intensity = 359 μE m−2 s−1. The highest maximum specific growth rate (0.07 h−1) and volumetric biomass production (1.25 mg/(L h)) values were achieved in the culture with 50% of OMW (v/v). The final biomass obtained had a high percentage of carbohydrates, whose content ranged from 30.3% to 89.2% and the highest lipid content (34.2%) was determined in the culture with 25% of OMW (v/v). The final treated water is suitable for its use in irrigation, discharge to receiving waters or for being reused in the same process.

Real olive oil mill wastewater treatment by photo-Fenton system using artificial ultraviolet light lamps

Large volume of untreated olive oil mill wastewater (OMW) is being stored in evaporation rafts. Given the high organic load and the presence of phenolic compounds in OMW, an effective treatment process should be implemented. In this work, an advanced oxidation process (photo-Fenton) operating in a batch reactor was used to treat OMW. All experiments were developed using FeCl3 as a catalyst. Different H2O2 concentrations (5.0, 8.0, 11.0, 15.0, 16.0, 21.0, 24.0 and 30.0 g/L) were studied as well as four commercial medium pressure UV-lamps (Standard, Z1, Z2 and Z3). The common operation conditions were: pH = 3, temperature 20 °C, [catalyst] = 3.0 g/L and direct ultraviolet light (UV-light). The samples were analysed at different times during the experiments to determine water quality parameters. In general, high total carbon, total organic carbon, total phenolic compounds and turbidity removal percentages (>90%) were registered in all experiments, at all oxidant concentrations studied. Increasing oxidant concentrations did not imply a noticeable rise on the final removal percentages (approximately 5% at these experimental conditions). Total nitrogen content removal percentages were determined and varied in the range of 62.5–75.5%. UV-lamps presented virtually similar removal percentages with the following averages COD = 95.7 ± 0.53%, total phenolic compounds = 93.6 ± 2.5%, total carbon = 94.0 ± 1.2%, total organic carbon = 96.3 ± 0.6%, total nitrogen = 74.9 ± 6.8% and turbidity 92.5 ± 1.9%.

Distribution of Mixing Efficiency in a Split-Cylinder Gas-Lift Bioreactor with Immobilized Yarrowia Lipolytica Cells Used for Olive Oil Mill Wastewater Treatment

The distribution of mixing in a split-cylinder gas-lift bioreactor has been investigated for suspensions of immobilized Yarrowia lipolytica cells with particles diameter varying between 3 and 4.2 mm. The results indicated important variation of mixing time on the height of riser or downcomer, as well as different behavior of suspensions flows in these two regions. Therefore, for the riser, the mixing efficiency increases from its bottom to the top, allowing the biocatalyst particles with intermediate size (3.6-mm diameter) reaching the most intense circulation of suspension. The analysis of the suspension flow in the downcomer region revealed that the intermediate positions are associated with the highest mixing mainly for the largest immobilized yeast particles (4.2-mm diameter). In both cases, the influence of aeration on turbulence extent is positive only for air superficial velocity up to 1.05–1.35 × 10−3 m/s, the magnitude of this effect being correlated with the biocatalyst size and position on the riser or downcomer. By means of the experimental data, mathematical correlations for mixing time have been proposed for each circulation region, taking into consideration both the operational parameters and the distance from the bioreactor bottom. These equations offer a good concordance with the experiment, the average deviation being of 5.82% for the riser and 6.06% for the downcomer zone.

The combination of coagulation, acid cracking and Fenton-like processes for olive oil mill wastewater treatment: phytotoxicity reduction and biodegradability augmentation.

Olive oil mill wastewater (OOMW) is one of the most important industrial wastewaters in the world due to high organic load and phenolic compounds. In this study, an integration of three processes including coagulation, acid cracking and Fenton-like was evaluated to treat OOMW. The performance of alum, ferric chloride and polyaluminum chloride was studied as coagulants. Among coagulants, ferric chloride showed the best results in comparison with the others. Coagulation process with FeCl3 removed 91.2% chemical oxygen demand (COD), 91.3% phenol, 98.9% total suspended solids and 99.2% turbidity at condition of pH = 6 and 3,000 mg/L coagulant dosage. Acid cracking process following the coagulation process with ferric chloride could slightly degrade organic compounds and provided suitable condition for the next process. Fenton-like process with zero valent iron (ZVI) was applied after coagulation and acid cracking. The optimal removal efficiency was achieved by Fenton-like process which was accomplished in condition of 7 g/L ZVI, 1,000 mg/L H2O2 and 180 min reaction time. The biodegradability of final effluent of this integration was improved significantly and biochemical oxygen demand5/COD value increased from 0.14 to 0.83. The results of germination tests revealed that phytotoxicity of the final effluent decreased.

COMPARATIVE STUDIES ON KINETICS OF ANAEROBIC AND AEROBIC BIODEGRADATION OF LIPIDS FROM OLIVE OIL MILL WASTEWATERS WITH MIXTURE OF Bacillus spp. CELLS

The experiments on the olive oil mill wastewater treatment for removing the lipids by anaerobic and aerobic biodegradation with mixed Bacillus spp. culture indicated that the rate of the aerobic process is up to two times higher than that of the anaerobic one. In this context, it was found that the influence of the dissolved oxygen concentration on the lipids biodegradation process is significant, but the kinetic model given in literature does not consider this parameter. Therefore, using the dependence between the ratio of specific rates, for aerobic and anaerobic processes, and the concentration of oxygen dissolved in medium, the new model

Mixed matrix membrane application for olive oil wastewater treatment: Process optimization based on Taguchi design method

Olive oil mill wastewater (OMW) is a concentrated effluent with a high organic load. It has high levels of organic chemical oxygen demand (COD) and phenolic compounds. This study presents a unique process to treat OMW. The process uses ultrafiltration (UF) membranes modified by a functionalized multi wall carbon nano-tube (F-MWCNT). The modified tube has an inner diameter of 15–30 nm and is added to the OMW treatment process to improve performance of the membrane. Tests were done to evaluate the following operating parameters of the UF system; pressure, pH and temperature; also evaluated parameters of permeate flux, flux decline, COD removal and total phenol rejection.The Taguchi robust design method was applied for an optimization evaluation of the experiments. Variance (ANOVA) analysis was used to determine the most significant parameters affecting permeate flux, flux decline, COD removal and total phenols rejection. Results demonstrated coagulation and pH as the most important factors affecting permeate flux of the UF. Moreover, pH and F-MWCNT UF had significant positive effects on flux decline, COD removal and total phenols rejection. Based on the optimum conditions determined by the Taguchi method, evaluations for permeate flux tests; flux decline, COD removal and total phenols rejection were about 21.2 (kg/m2 h), 12.6%, 72.6% and 89.5%, respectively. These results were in good agreement with those predicted by the Taguchi method (i.e.; 22.8 (kg/m2 h), 11.9%, 75.8 and 94.7%, respectively). Mechanical performance of the membrane and its application for high organic wastewater treatment were determined as strong.

Removal of phenolic compounds in olive mill wastewater by silica–alginate–fungi biocomposites

This study aims to attempt a treatment strategy based on fungi immobilized on silica-alginate (biocom- posites) for removal of phenolic compounds in olive oil mill wastewater (OMW), OMW supplemented (OMWS) with phenolic compounds and water supplemented (WS) with phenolic compounds, thus decreasing its potential impact in the receiving waters. Active (alive) or inactive (death by sterilization) Pleurotus sajor caju was encapsu- lated in alginate beads. Five beads containing active and inactive fungus were placed in a mold and filled with silica hydrogel (biocomposites). The biocomposites were added to batch reactors containing the OMW, OMWS and WS. The treatment of OMW, OMWS and WS by active and inactive biocomposites was performed throughout 28 days at 25 C. The efficiency of treatment was evaluated by measuring the removal of targeted organic compounds, chemical oxygen demand (COD) and relative absorbance ratio along the time. Active P. sajor caju biocomposites were able to remove 64.6-88.4 % of phenolic compounds from OMW and OMWS and 91.8-97.5 % in water. Fur- thermore, in the case of OMW there was also a removal of 30.0-38.1 % of fatty acids, 68.7 % of the sterol and 35 % of COD. The silica-alginate-fungi biocomposites showed a high removal of phenolic compounds from OMW and water. Furthermore, in the application of biocomposites to the treatment of OMW it was observed also a decrease on the concentration of fatty acids and sterols as well as a reduction on the COD.