Volume 4 Special Issue 1 2010
Olive Mill Waste Water in the Mediterranean Area
How to reference: Giuffrida M (2010) European and Italian Laws for the Agronomic Use of Olive-Oil Mill Wastewaters. In: Musculo A (Ed) Olive Mill Waste Water in the Mediterranean Area. Terrestrial and Aquatic Environmental Toxicology 4 (Special Issue 1), 1-6
Dipartimento GESAF, Facoltà di Agraria Università “Mediterranea” Reggio Calabria Feo di Vito, Italy
CONTENTS AND ABSTRACTS
Marianna Giuffrida (Italy) European and Italian Laws for the Agronomic Use of Olive-Oil Mill Wastewaters (pp 1-6)
Invited Mini-Review: This work examines current Italian and European Union legislation not only as regards the agronomic use of olive-oil mill wastewater but also community aids direct to support olive-oil producers’. What clearly emerges from the research is above all, the willingness of community and Italian law makers’ to protect the environment through the correct use of the resources available and by transforming possible waste matter into effectively usable resources. Although not apparently connected, what also emerges is the strong link between the two areas of legislation: environmental conservation and safeguarding the economic interests of producers. In other words, it appears that the latter can be pursued without causing prejudice to the former. However, this does imply a strict adherence to the limits set for the spreading of olive-oil mill wastewater onto the soil, limits which are considered appropriate to guarantee a fair balance between the two opposing interests.
Dimitrios Kalderis, Evan Diamadopoulos (Greece) Valorization of Solid Waste Residues from Olive Oil Mills: A Review (pp 7-20)
Invited Review: The solid waste residues from olive oil mills constitute an environmental threat if disposed of in the natural environment, as it is common practice in many areas. This review summarizes the efforts of the scientific and technical community to develop appropriate technologies for the valorization of these wastes. The majority of the research towards this purpose focuses on the recovery of high-added value compounds, the production of adsorbents, the production of compost or soil amendment products, and applications related to energy generation either through biotechnological processes or through advanced thermal processes.
Georgia Ouzounidou, Georgios I. Zervakis, Fragiskos Gaitis (Greece) Raw and Microbiologically Detoxified Olive Mill Waste and their Impact on Plant Growth (pp 21-38)
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Invited Review: Olive-oil production is of vital importance for the economy and social life of the Mediterranean region; however, the side effect of the olive-oil mill activity is the generation of enormous quantities of biotoxic olive-mill waste within a short period of three months. Numerous physicochemical and biological methods have been used in the past for the treatment of both olive mill wastewater (OMWW, deriving from three-phase extraction systems) and two-phase olive mill waste (TPOMW, deriving from two-phase extraction systems), but these generally failed to come up with a viable solution of wide applicability. On the other hand, since olive mill waste are of purely vegetative origin, their recycling (either raw or after treatment, including composting) into agricultural ecosystems seems environmentally reasonable and financially feasible. The detoxification and biotransformation potential of naturally occurring and other microorganisms is a promising alternative to the previous approach, especially in cases where in situ decomposition of such waste can not be readily applied. Raw and detoxified (chemically and microbiologically) olive mill waste application on tree and crop cultivation, showed that there is differentiation of plant responses depending on the plant species, type of the growth substrate and time of exposure. Based on hydroponics, soil and soilless cultures it appears that the higher the organic matter in the growth medium, the lower the waste toxicity. The toxicity is evident in all the plant functions from the germination to organs morphology, physiology, metabolism, ultrastructure, ripening and quality of the final product.
Giuseppe Celano, Assunta Maria Palese, Mimmo Parente, Luca Rizzuti, Nicola Silvestri (Italy) Environmental Impact Evaluation of Olive Mill Wastewater Shedding on Cultivated Fields (pp 39-44)
Invited Mini-Review: The olive oil industry in Europe produces a significant amount of olive mill wastewater (OMW) which poses a serious environmental threat if its disposal is not carried out correctly. At the same time, OMW is an important source of useful substances for several activities (e.g. for food, chemical and energy industries; in agriculture as a fertiliser, as a resource for organic matter). Currently in Italy OMW shedding on cultivated fields seems to be the most viable solution. Disposing of OMW appropriately requires specific data on wastewater management (OMW doses and type, the latter depending on the olive oil extraction system, and distribution modality), the shed field (soil type and features, crop typologies, agricultural practises), and the climatic pattern of the area where the field is located. All these data, considered in an integrated evaluation procedure based on the fuzzy logic theory (Sugeno technique), means that the agro-environmental risk can be assessed by calculating a synthetic index ascribable to a specific hypothesis of OMW shedding. This paper presents a multiplatform software application called ICABAS. The software has been adapted to the current Italian legislation and the specific environmental conditions of the Basilicata Region where it has been integrated into the regional laws for olive mill residue management. The evaluation procedure is easy to use and provides a useful tool for administrative and technical purposes and also to support decision systems, at a policy level, for the sustainable management of the resources involved.
Carla Amaral, Rosário Anjos, Célia Pais (Portugal) Bioremediation of Olive Mill Wastewaters with Fungi (pp 45-56)
Invited Review: Olive Mill Wastewaters (OMW), the residual waters from olive oil extraction industry, are considered the main environmental problem in the Mediterranean area. Due to their high organic loads, and high amounts of organic acids and phenolic compounds, OMW are toxic to several groups of organisms, therefore their reutilization need previous treatment. Decolourization and dephenolization of OMW seem to be the most difficult drawback of the treatments tested so far. However, several fungal species have been successfully used to eliminate colour and phenolics from OMW, reducing toxicity and allowing other types of chemical or physical treatments like anaerobic digestion. This paper presents a brief review of OMW biological treatments by filamentous fungi and yeast like fungi, giving special attention to species able to metabolise some of the recalcitrant compounds.
Serafina Andiloro, Giovanni Aramini, Anna Maria Corea, Vincenzo Tamburino, Demetrio Antonio Zema, Santo Marcello Zimbone (Italy) Planning Agricultural Utilization of Olive Oil Mill Wastewater: A Framework Model and Implementation Example in a Mediterranean Area (pp 57-64)
Original Research Paper: The management of olive oil mill wastewater (OMW) poses relevant technical and economic problems due to some factors, such as: the high qualitative and quantitative variability of effluents (mainly due to the seasonal nature of fruit processing); the geographic dispersion of oil mills; the high concentration of organic matter and inhibiting compounds (e.g. polyphenols). Among the different alternatives for OMW management, agricultural utilization, which has been practised for a long time, is able to assure cheapness, reliability and environmental sustainability, using low technology and requiring lower costs. This practice helps to avoid water body and soil pollution, to reduce costs of OMW management and to exploit the fertilising properties of OMW for both herbaceous and tree crops. An evaluation of the soil’s suitability for OMW application is needed to allow the planning and monitoring activities of effluent agricultural utilization, thereby avoiding the uncontrolled disposal of OMW and the subsequent environmental risks. An assessment framework model has been therefore purposely arranged and implemented in the Calabrian region. On the basis of the soil morphological, hydrological and pedologic properties, the fundamental geographic are classified by the model in hierarchical levels (orders, classes and sub-classes) of soil’s suitability for OMW application, eventually specifying the kind of restrictions. Model implementation in the Calabrian region (Italy) has allowed the drawing-up of the “Plan of OMW agricultural utilization” at 1:250.000 scale (which integrates the technical rules for the agricultural utilization of OMW adopted in 2006 by the Calabrian region) and has pointed out that the geographic distribution of soils suitable for agricultural utilization of OMW basically corresponds to the main olive productive districts.
Antonina Capra, Vincenzo Tamburino, Santo Marcello Zimbone (Italy) Irrigation Systems for Land Spreading of Olive Oil Mill Wastewater (pp 65-74)
Original Research Paper: Mill wastewater has always created considerable environmental problems for countries producing olive oil. These problems, which are of increasing relevance in relation to the growing interest in protecting water resources, are of technical and economic nature and are mainly due to the quality of the wastewater (which contains a large amount of organic substances and solute or suspended minerals, and is highly fermentable), the seasonal nature of the production process, and the great territorial dislocation of the olive mills. In order to obtain wastewater which complies with current environmental legislation regarding discharge into water supply systems, it is necessary to use treatment plants with high running costs, which can be prohibitive in olive processing activities. Accumulation and subsequent distribution on the soil through irrigation plants may represent a sustainable solution to the various problems connected with olive mill wastewater (OMW) disposal. Besides allowing for a considerable saving in costs, the use of irrigation plants allows optimal distribution of wastewater. With gradual and uniform distribution, phytotoxic organic substances are held and broken down in the surface layer of the soil, far from the roots of the trees and from water tables. Several experiments highlight that the effects of OMW on crops, soils and the environment depend on the quantity of OMW distributed, but very little information on optimal systems and modalities used to spread OMW is available. A gradual, uniform distribution of OMW can be obtained through microirrigation systems. However, some system management problems may occur. In fact, the small orifices of the emitters and the filters used to protect them can be clogged by small particles or growths due to the suspended solid content of OMW, mainly of organic type. The paper discusses both agronomic and operational aspects of OMW spreading. According to the analysis, some practical recommendations for agronomic OMW use by microirrigation systems are made.
Adele Muscolo, Maria Sidari, Carmelo Mallamaci, Emilio Attinà (Italy) Effects of Olive Mill Wastewater on Seed Germination and Seedling Growth (pp 75-83)
Original Research Paper: Olive mill wastewater (OMW) is considered as phytotoxic and thus an environmentally hazardous material. Therefore, alternative areas of application have been discussed; one of these might be its use as an additive in growing media for agricultural purposes. However, phytotoxic responses might occur at higher concentrations. The objective of the present study was to determine threshold levels for application of OMW in agriculture. The hypotheses were that (i) high concentrations of OMW are detrimental to seed germination and seedling growth, (ii) toxicity caused by OMW may be removed through sedimentation in a settling basin prior to addition. Data obtained showed that low concentrations of OMW did not reduce seed germination and seedling growth. However, higher concentrations showed significant differences in almost all the evaluated parameters. The addition of raw OMW at high concentrations (over 50%) reduced strongly in vitro seed germination, a- and β-amylase activities. The great toxicity of the OMW observed in an in vitro experiment decreased drastically when the same OMW was utilized onto soil in microcosm, showing a decrease at about 35% in germination for fava (Vicia faba L.), sulla (Hedysarum coronarium L.), chicory (Cichorium intybus L.) and wheat (Triticum durum Desf.) seeds. These mean that the phytotoxic effects of OMW might be modified by chemical and biological processes in soil.
Gregorio Gullo, Valentino Branca, Serafino Cannavò, Antonio Dattola, Rocco Zappia (Italy) Irrigation Effects with Different Mixtures of Olive Mill Wastewater (OMW) and Clean Water on the Growth and Quality of Young Olive Plants cv. ‘Ottobratica’, in a Nursery (pp 84-90)
Original Research Paper: This study examines the effects of olive mill wastewater (OMW) combined with clean water (CW) in a nursery of olive plants (Olea europaea L.). Four treatments (Control = 0%, T1 = 5%, T2 = 18%, T3 = 46% OMW) were compared. From July to November, the amount of OMW given to cv. ‘Ottobratica’ olive plants ranged from 0 ml in control plants to 1540 ml per plant in T3. The increase in shoot development was higher in T1 (6.25 cm) and in T2 (4.51 cm) compared to the control plants (1.96 cm). In T3 a decrease in shoot development (0.88 cm) was evident. Absorbent root length was statistically higher in T1 (157 m) than in T2 (85 m) and T3 (74 m), decreasing as the OMW% in the mixture increased. Stomatal conductance increased by 144% in T1, 35% in T2 and 42% in T3 compared to control plants. In T1, T2 and T3 the leaf area and stomatal conductance decreased with a reduction in length of the absorbent roots due to the higher OMW% in the mixture. The potassium level was highest in T1, but no significant differences were observed in the other treatments compared to the control. The total dry weight per plant increased by 28% in T1 and decreased ~12% in T2 and T3, compared to the control plants. OMW, if diluted, can be considered a valid fertilizer and interesting ecological and economic solution in olive nurseries.
Carmelo Santonoceto, Umberto Anastasi (Italy) Agronomic Exploitation of Olive Oil Mill Wastewater: Effect on Growth and Yield of Field Crops and Impact on Soil Fertility (pp 91-103)
Original Research Paper: In Mediterranean countries, olive oil mills generate a liquid waste that could represent a potential source of pollution or an agronomic opportunity if recycled as fertiliser within the agrosystems. Hence, the effects of applying increasing amount of this effluent (0, 8, 16, 32 l m-2) on growth and productive response of a series of field crops (forage sorghum, faba bean, durum wheat, berseem, malting barley, sulla meadow) as well as on the main soil properties were studied. The research was conducted in southern Italy using lysimeters as plots. The results highlighted that with the exception of faba bean, which experienced phytotoxicity with deleterious effects at higher rates of the effluent, the other tested crops were not penalised and responded positively in terms of plant survival, growth and yield as the waste supply increased within certain limits. Therefore, each crop reached the best productive performance with different level of residue. However, the favourable rainfall regime during the growing season of the crops played a key role. At soil level, changes emerged between the start and the end of the experiment for the analysed features, except those for pH and EC. Overall, the organic pool of the soil was relatively preserved, whereas an enhancement occurred for C.E.C. and for macronutrients, mainly P and K. The micronutrient levels also varied differently. However, the final variations of the soil characteristics were not always univocally sustained by the different waste rates. In conclusion, there are real possibilities of agronomic reutilisation of the waste in cropping systems typical of southern Italy, but others research into farming studies are needed to acquire a better evaluation of the environmental impact.
Maria Sidari, Carmelo Mallamaci, Emilio Attinà, Adele Muscolo (Italy) Response of Soil Properties and Microbial Communities to the Application of Olive Mill Wastewaters (pp 104-108)
Original Research Paper: A laboratory trial was carried out to evaluate the short-term influence of different concentrations of olive mill wastewaters (OMW) on soil physico-chemical properties and microbial community. After 30 days’ incubation, no significant changes occurred in soil pH values and humified organic carbon; soil organic carbon and total water-soluble phenols (WSP) significantly increased. Addition of OMW to the soil caused modification in microbial counts and microbial community structure. Bacteria decreased significantly up to 86% for 100% OMW treatment. No significant differences were found for fungal community in the soil treated up to 50% OMW while a decrease in 50% was found when 100% OMW was applied. The fungal: bacteria ratio increased significantly. The actinomycetes CFU (colony forming units) decreased gradually up to a maximum of 38% when OMW dose increased. Our results evidenced that the storage of OMW in open-air lagoons for a 4-month period before its soil application and the appropriate dilution with irrigation water without any further treatment can be an inexpensive technology to be adopted by small-sized olive mills.
Giorgos Markou, Dimitris Georgakakis, Katerina Plagou, Georgia Salakou, Nikoletta Christopoulou (Greece) Balanced Waste Management of 2- And 3-Phase Olive Oil Mills in Relation to the Seed Oil Extraction Plant (pp 109-112)
Original Research Paper: Olive oil extraction process produces a considerable amount of olive oil mill wastes (OMW) and wastewaters (OMWW) which have a high pollutant load. There are several OMWW treating methods but in most of the cases they are expensive and complex processes and thus they are prevented from being applied in the small-to-medium size olive oil mills (OM), which in the case of Greece are the majority. The 2-phase OMW due to their high moisture content are not accepted from seed oil extraction plants (SOEP) and as a result a waste management problem emerges. Consequently, the 3-phase OM owners refrain from applying the 2-phase olive oil extraction process, but inside the residential districts, where land dispose is lacking, the OM have to operate in the 2-phase olive oil extraction mode. In this paper it is shown that mixing 2-phase OMW with deoiled olive seeds (DOS) in a mass ratio of 2: 1 creates a mixture which has a moisture content that makes it suitable for handling in an SOEP and thus it could be easily accepted for seed oil extraction. As a result the existence of 2-phase OM in a wide region should be necessarily accompanied by a certain number of 3-phase OM. According to this suggestion all OM operating inside or near residential districts would operate exclusively in the 2-phase mode, while the accompanying 3-phase OM would operate outside the residential districts. To investigate the required 3-phase OMW treating process, a pilot-scale sedimentation-evaporation unit has been constructed and operated in Evia, Greece. A linear volume reduction of 0.47% per day was obtained for the sediment.
Ben Sassi Abdelhadi, Mohamed Benlemlih, Saad Ibnsouda Koraichi, Lahcen Ahansal, Aayah Hammoumi, Abdellatif Boussaid (Morocco) Suitability of Yeasts for the Treatment of Olive Mill Wastewater (pp 113-117)
Research Note: Olive mill wastewater (OMW) is strongly hindered by high concentration of phenolics, which is considered the main cause of its toxicity. Despite this high level of phenolics, yeasts are the dominant microorganisms with levels as high as 106 colony forming units/ml. The identification of yeast isolates from freshly produced OMW from olive oil plants, stored OMW in ponds and larvae of the olive fly Bactrocera oleae revealed that many species are common in these environments along with olives. Some strains of Candida holstii, C. diddensiae, C. boidinii, Pichia guillermondii and Geotrichum candidum were able to grow and reduce phenolics concentration in the OMW. However, phenolics reduction was lower than 50% raising the question if yeasts degrade or simply adsorb the phenolics to their cell walls. A review of the literature reveals that a few species of Trichosposron cutaneum and more recently Candida tropicalis, C. matosa,and C. aquatextoris can grow solely on phenol and other aromatics. Some investigations have also identified phenol degradation products while others revealed the ability of yeasts to produce aromatic-degrading enzymes such as phenol hydroxylase. These findings, along with the possibility of producing economically valuable products from yeasts, can contribute to design a successful treatment process of OMW using yeasts. The evaluation of ethanol production revealed that OMW-isolated strains, C. holstii and C. ernobii, produced ethanol with efficiencies higher than 90% theoretical yield. In addition, these two yeast strains can use xylose and galactose readily available in wood and whey wastes that could potentially be codigested with OMW.
Serap Saglik Aslan (Turkey) Olive Oil Recovery Methods (pp 118-119)
Techniques Paper: Olive mill wastewater is formed during olive oil production and is also an important environmental problem in the Mediterranean area. The amount of oil and grease, which is the one of the parameters used for the characterization of this wastewater, cannot be determined easily using a standard method. This review focuses on the progress in olive oil recovery methods used for dealing with the environmental problem of olive mill wastewater. Studies have been conducted with the aim either to increase the efficiency of oil recovery using established methods or to develop novel methods. A number of methods and various reactives have been evaluated for these purposes.