scholarly journals Time domain reflectometry for dielectric characterization of olive mill wastewater contaminated soils

2020 ◽  
Vol 51 (4) ◽  
pp. 248-254
Author(s):  
Alessandro Comegna ◽  
Antonio Coppola ◽  
Giovanna Dragonetti

Olive mill wastewater (OMW) is a compound originating from oil mills during oil extraction processes. In the Mediterranean area, more than 30 million m3 of OMW are produced each year, which represents 95-97% of the world production. Such volumes of untreated OMW are usually directly disposed of into drainage systems, water bodies (such as streams, lagoons and ponds) or are sprinkled on soils, causing potentially severe environmental problems to soils and groundwater. Consequently, there is a serious waste management problem related to the olive oil industry, because these practices no longer being acceptable. In the case of on-land OMW disposal, the characterization and the identification of this contaminant in soils is a fundamental task especially with a view to maintaining the integrity and quality of agroecosystems. In recent years, soils have been extensively studied to detect contaminants by using various geophysical methods. Among such techniques, time domain reflectometry (TDR) has shown, in different contexts, evident sensitivity and resolution capability for the characterization of contaminated soil sites. In order to further exploit the potential of the TDR technique, in this study we conducted a series of laboratory-controlled tests to explore how OMW influences the dielectric response of contaminated soils. This investigation led to the development of an empirical dielectric model to estimate the presence of OMW in variably saturated-contaminated soils with different textures and pedological features. In particular, the soils selected belong to two typical pedological units in southern Italy which account for approximately 90% of the Italian olive plantations and one of the highest concentrations of the olive oil industry in Italy. In these districts, as well as in other European and Mediterranean countries, there is the controversial habit to spread OMW on soils.

2020 ◽  
Author(s):  
Alessandro Comegna ◽  
Antonio Coppola ◽  
Giovanna Dragonetti

Abstract. Olive mill wastewater (OMW) is a compound originating from oil mills during oil extraction processes. In the Mediterranean area, more than 30 million m3 of OMW are produced each year, which represents 95–97 % of world production. Such volumes of untreated OMW are usually directly disposed of into drainage systems, water bodies (such as streams, lagoons and ponds), or else are sprinkled on soils, causing potentially severe environmental problems to soils and groundwater. There is thus a serious waste management problem related to the olive oil industry, such practices no longer being acceptable. In the case of on-land OMW disposal, characterization and identification of this contaminant in soils is a fundamental task especially with a view to maintaining the integrity and quality of agroecosystems. In recent years, soils have been extensively studied to detect contaminants by using various geophysical methods. Among such techniques, time domain reflectometry (TDR) has shown, in different contexts, evident sensitivity and resolution capability for characterizing contaminated soil sites. In order to further exploit the potential of the TDR technique, in the present study we conducted a series of laboratory-controlled tests to explore how OMW influences the dielectric response of contaminated soils. The research led to the development of an empirical dielectric model to estimate the presence of OMW in variably saturated-contaminated soils with different textures and pedological features.


2009 ◽  
Vol 59 (10) ◽  
pp. 2017-2027 ◽  
Author(s):  
L. M. Nieto ◽  
G. Hodaifa ◽  
S. R. Vives ◽  
J. A. G. Casares ◽  
S. B. Driss ◽  
...  

This study offers a solution for reducing the environmental effect of wastewaters generated by the olive-oil industry. Olive-oil companies produce variable quantities of wastewaters, which require treatment for disposal or reuse. Today, regulations are becoming increasingly strict regarding the parameters measured in these effluents. In Spain, the resolution by the president of the Hydrographical Confederation of the Guadalquivir on water use 2004 set parameter limits as follows: pH = 6.0–9.0, total suspended solid = 500 mg/L; and COD and BOD520=1,500 mg O2/L. For the year 2006, maximum values for COD and BOD520 were fixed at 1,000 mg O2/L. To solve this problem, a study has been made to derive irrigation water from the above-mentioned effluents through chemical oxidation based on the Fenton's process. This would be first step towards using a closed-circuit system in olive-oil mills to treat and reuse effluents.


Author(s):  
A. Comegna ◽  
G. Dragonetti ◽  
R. Kodesova ◽  
A. Coppola

AbstractThe Mediterranean area concentrates the world’s largest production area of olive oil. The olive oil industry represents, in this basin, one of the leading sectors of the agri-food economy. Olive mill water (OMW) is the principal waste effluent produced by the olive oil industry. Due to its high pollution load, this aqueous by-product cannot be directly disposed of in domestic wastewater treatment plants (especially those with a biological treatment unit). Untreated OMW is currently used for agronomic purposes in several countries, mainly because it is rich in valuable plant nutrients. However, OMW is characterized by toxic phenols, high organic matter, high salinity, suspended solids and several other components that may have possible negative effects on chemical and physical soil properties, as well as soil biological activities. In the present research, we focused on the effects of OMW application on transport and hydraulic soil properties. Three distinct soils from a pedological point of view were selected and a series of laboratory steady-state miscible flow tests were conducted under saturated conditions, on both OMW-treated and -untreated soil columns. Tests were conducted on disturbed and undisturbed soil columns. The approach proposed by Kachanoski, based on soil impedance (Z) measurements via the time domain reflectometry (TDR) technique, was used to monitor the leaching experiments. The breakthrough curves (BTCs) exhibited different shapes that allowed the repercussions of OMW applications on soil transport behaviour to be distinguished. Several additional tests conducted on OMW-treated and -untreated soil cores to determine water retention curves (SWRCs) and saturated hydraulic conductivity Ks allowed us to infer the probable mechanisms involved in soil hydrological behaviour changes under OMW treatments. The results show that when OMW leaches into the soil immediately after its disposal there is little effect on the evaluated hydraulic and hydrodispersive properties. By contrast, we demonstrated that a short incubation period (i.e. a short contact time between OMW and soil) of 10 days is enough to exert a great influence on all the values determined (e.g. soil pore velocity v and Ks reduced by up to one order of magnitude). These effects were especially evident in undisturbed soil samples. Graphic Abstract


Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 876 ◽  
Author(s):  
Bruno M. Esteves ◽  
Sergio Morales-Torres ◽  
Francisco J. Maldonado-Hódar ◽  
Luis M. Madeira

A series of biochars and activated carbons (ACs) was prepared combining carbonization and physical or chemical activation of cheap and abundant residues of the olive oil industry. These materials were used as Fe-support to develop low-cost catalysts for the heterogeneous Fenton-like oxidation of simulated olive mill wastewater (OMW), the highly pollutant effluent generated by this agroindustry. Commercial ACs were also used as reference. All catalysts prepared were extensively characterized and results related with their performances in the catalytic wet peroxide oxidation (CWPO). Results showed a linear relationship of the textural properties of the catalysts with the adsorptive and catalytic performance, as well as the preferential adsorption and degradation of some phenolic compounds (caffeic and gallic acids) by specific interactions with the catalysts’ surface. Despite the best performance of catalysts developed using commercial supports, those prepared from agro-industrial residues present some advantages, including a smaller catalyst deactivation by iron leaching. CWPO results show that catalysts from physically activated olive stones are the most promising materials, reaching total organic carbon and toxicity reductions of 35% and 60%, respectively, as well an efficient use of H2O2, comparable with those obtained using commercial supports. This approach showed that the optimized treatment of this type of residues will allow their integration in the circular economic process of the olive oil production.


Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 800
Author(s):  
Anna Maria Posadino ◽  
Annalisa Cossu ◽  
Roberta Giordo ◽  
Amalia Piscopo ◽  
Wael M Abdel-Rahman ◽  
...  

This work aims to analyze the chemical and biological evaluation of two extracts obtained by olive mill wastewater (OMW), an olive oil processing byproduct. The exploitation of OMW is becoming an important aspect of development of the sustainable olive oil industry. Here we chemically and biologically evaluated one liquid (L) and one solid (S) extract obtained by liquid–liquid extraction followed by acidic hydrolysis (LLAC). Chemical characterization of the two extracts indicated that S has higher phenol content than L. Hydroxytyrosol and tyrosol were the more abundant phenols in both OMW extracts, with hydroxytyrosol significantly higher in S as compared to L. Both extracts failed to induce cell death when challenged with endothelial cells and vascular smooth muscle cells in cell viability experiments. On the contrary, the higher extract dosages employed significantly affected cell metabolic activity, as indicated by the MTT tests. Their ability to counteract H2O2-induced oxidative stress and cell death was assessed to investigate potential antioxidant activities of the extracts. Fluorescence measurements obtained with the reactive oxygen species (ROS) probe H2DCF-DA indicated strong antioxidant activity of the two OMW extracts in both cell models, as indicated by the inhibition of H2O2-induced ROS generation and the counteraction of the oxidative-induced cell death. Our results indicate LLAC-obtained OMW extracts as a safe and useful source of valuable compounds harboring antioxidant activity.


2011 ◽  
Vol 2011 ◽  
pp. 1-14 ◽  
Author(s):  
Antonis A. Zorpas ◽  
Vassilis J. Inglezakis

The annual olive oil production in Cyprus is in the range of 2700–3100 t y−1, resulting in the generation of significant amount of waste. The cocomposting of the olive oil solid residue (OOSR) and the treated wastewaters (with Fenton) from the olive oil production process with the application of reed beds has been studied as an integrated method for the treatment of wastewater containing high organic and toxic pollutants under warm climate conditions. The experimental results indicated that the olive mill wastewater (OMW) is detoxified at the end of the Fenton process. Specifically, COD is reduced up to 65% (minimum 54.32%) by the application of Fenton and another 10–28% by the application of red beds as a third stage. The final cocomposted material of OOSR with the treated olive mile wastewater (TOMW) presents optimum characteristics and is suitable for agricultural purpose.


2012 ◽  
Vol 66 (12) ◽  
pp. 2505-2516 ◽  
Author(s):  
J. M. Ochando-Pulido ◽  
A. Martinez-Ferez

Direct disposal of the heavily polluted effluent from olive oil industry (olive mill wastewater, OMW) to the environment or to domestic wastewater treatment plants is actually prohibited in most countries, and conventional treatments are ineffective. Membranes are currently one of the most versatile technologies for environmental quality control. Notwithstanding, studies on OMW reclamation by membranes are still scarce, and fouling inhibition and prediction to improve large-scale membrane performance still remain unresolved. Consequently, adequately targeted pretreatment for the specific binomium membrane-feed, as well as optimized operating conditions for the proper membranes, is today's challenge to ensure threshold flux values. Several membrane materials, configurations and pore sizes have been elucidated, and also different pretreatments including sedimentation, centrifugation, biosorption, sieving, filtration and microfiltration, various types of flocculation as well as advance oxidation processes have been applied so far. Recovery of potential-value compounds, such as a variety of polyphenols highlighting oleuropein and hydroxytyrosol, has been attempted too. All this research should constitute the starting point to proceed with OMW purification beyond recycling for irrigation or depuration for sewer discharge, with the aim of complying with standards to reuse the effluent in the olive oil production process, together with cost-effective recovery of added-value compounds.


Sign in / Sign up

Export Citation Format

Share Document