Chemical Characteristics of Two-Phase Olive-Mill Waste and Evaluation of Their Direct Soil Application in Humid Mediterranean Regions

Podgornik, Maja; Bučar-Miklavčič, Milena; Levart, Alenka; Salobir, Janez; Rezar, Vida; Butinar, Bojan

doi:10.3390/agronomy12071621

Cited by 9 publications

(6 citation statements)

References 27 publications

(51 reference statements)

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“…In a trial in a sub-humid region of Slovenia with high application rates (80 t/ha), significant increases in soil C org were found one year after application [28]. However, in a three-year trial in a non-irrigated olive grove in Italy, applying 75 t/ha spread directly under trees, no effects on soil C org were found, which was attributed to a rapid mineralization (possibly owing to the additional urea fertilization) [16].…”

Section: Effects Of Alperujo Application On Soil Organic Carbonmentioning

confidence: 99%

Is the Direct Soil Application of Two-Phase Olive Mill Waste (Alperujo) Compatible with Soil Quality Protection?

García-Randez,

Marks,

Pérez-Murcia

et al. 2023

Agronomy

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In Spain and other Mediterranean countries, significant quantities of semi-solid olive mill waste are generated, which should be preferentially applied to agricultural soils to close nutrient cycles. However, two-phase olive mill waste (termed alperujo in Spanish) is known to pose risks to soil quality and plant production when applied to soil in large quantities. Alperujo has high contents of polyphenol substances, which can inhibit microbial growth and are also phytotoxic in nature. However, when applied in appropriate quantities and following specific methods, it is possible that the practice may not pose any risks, and this requires evaluation. As a waste management option, direct application of alperujo can supply plant nutrients and organic matter to degradation-prone Mediterranean soils. In order to validate this circular economy fertilization and soil protection strategy, an 18-month field experiment was undertaken, applying moderate quantities of alperujo on permanent crop groves throughout the Spanish region of Valencia. Eleven experimental parcels with permanent crops managed by farmers were identified to test two scenarios: a single application of 10 t/ha, and a second application of 10 t/ha after 10 months. Soil chemical parameters were assessed at 0, 6, 10, and 18 months. Soil organic carbon, total Kjeldahl nitrogen, pH, electrical conductivity, nitrates, and polyphenol contents were modified by alperujo application, but these effects were highly transient in nature, with generally no lasting effects after 4–6 months for either application scenario. Also, qualitative evaluations carried out by farmers revealed few effects, although some reductions in erosive processes and improvements in plant vigor were noted. As such, based on the measured parameters, it is concluded that the direct soil application of alperujo olive mill wastes at low application rates did not lead to any lasting detrimental effects on soil quality or compromise the productivity of permanent crops in this Mediterranean region.

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Section: Effects Of Alperujo Application On Soil Organic Carbonmentioning

confidence: 99%

Is the Direct Soil Application of Two-Phase Olive Mill Waste (Alperujo) Compatible with Soil Quality Protection?

García-Randez,

Marks,

Pérez-Murcia

et al. 2023

Agronomy

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“…The present work aims at discussing only the production and treatment of OMWW. OMWW composition is influenced by different factors, i.e., extraction methods, olives' type and origin, climate conditions, and cultivation/processing practices [21]. In general, it can be mainly summarized as follows (Figure 1): ca.…”

Section: An Insight Into the Eu Legislationmentioning

confidence: 99%

Olive Mill Wastewater Remediation: From Conventional Approaches to Photocatalytic Processes by Easily Recoverable Materials

et al. 2022

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Olive oil production in Mediterranean countries represents a crucial market, especially for Spain, Italy, and Greece. However, although this sector plays a significant role in the European economy, it also leads to dramatic environmental consequences. Waste generated from olive oil production processes can be divided into solid waste and olive mill wastewaters (OMWW). These latter are characterized by high levels of organic compounds (i.e., polyphenols) that have been efficiently removed because of their hazardous environmental effects. Over the years, in this regard, several strategies have been primarily investigated, but all of them are characterized by advantages and weaknesses, which need to be overcome. Moreover, in recent years, each country has developed national legislation to regulate this type of waste, in line with the EU legislation. In this scenario, the present review provides an insight into the different methods used for treating olive mill wastewaters paying particular attention to the recent advances related to the development of more efficient photocatalytic approaches. In this regard, the most advanced photocatalysts should also be easily recoverable and considered valid alternatives to the currently used conventional systems. In this context, the optimization of innovative systems is today’s object of hard work by the research community due to the profound potential they can offer in real applications. This review provides an overview of OMWW treatment methods, highlighting advantages and disadvantages and discussing the still unresolved critical issues.

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“…In the case of companies with large turnovers, it might be convenient, but the high-water content of biphasic pomace oil could make pomace oil extraction more expensive, difficult, and impactful, due to the high use of organic solvents and energy [73]. In addition, pomace management requires specific facilities (such as storage tanks with special valves, pumps, and tankers) [74]. Therefore, two-phase technology could transfer the problem of the olive waste disposal of the olive mill factory to the seed oil refineries.…”

Section: S2 and S4: Energy Destination-biogas Productionmentioning

confidence: 99%

Sustainability Assessment of Different Extra Virgin Olive Oil Extraction Methods through a Life Cycle Thinking Approach: Challenges and Opportunities in the Elaio-Technical Sector

et al. 2022

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Owing to its important nutritional features, extra virgin olive oil (EVOO) is one of the world’s highest-value products, mostly manufactured in Mediterranean countries. However, its production exerts several negative environmental effects, mainly related to the agricultural phase (and the use of fertilizers, pesticides, etc.) and waste management. Olive oil can be extracted from the olive paste using different extraction systems, including pressure, centrifugation, and percolation. In particular, EVOO by-product composition strictly depends on the extraction technologies, and two- or three-phase centrifugal extraction methods are usually employed. Therefore, due to olive oil’s economic value, it might be useful to investigate its environmental impacts, to advise sustainable supply chain models. In this context, a valuable tool for assessing the product’s environmental compatibility is the Life Cycle Assessment, which is part of a broader Life Cycle Thinking philosophy. This research focused on evaluating the EVOO environmental impact by comparing two- and three-phases extraction processes. Additionally, two scenarios, (i.e., composting and bio-gasification), were proposed to assess the best valorisation strategy for the produced pomace. The results showed that the two-step extraction process was more sustainable than the three-step one in nine out of nine considered impact categories. By milling 1000 kg of olives, the first technology approximately produces 212 kg CO2 eq, the latter 396 kg CO2 eq. Finally, pomace valorisation by bio-gasification was found as the best recovery process, able to confer greater environmental benefit than composting.

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Chemical Characteristics of Two-Phase Olive-Mill Waste and Evaluation of Their Direct Soil Application in Humid Mediterranean Regions

Cited by 9 publications

References 27 publications

Is the Direct Soil Application of Two-Phase Olive Mill Waste (Alperujo) Compatible with Soil Quality Protection?

Is the Direct Soil Application of Two-Phase Olive Mill Waste (Alperujo) Compatible with Soil Quality Protection?

Olive Mill Wastewater Remediation: From Conventional Approaches to Photocatalytic Processes by Easily Recoverable Materials

Sustainability Assessment of Different Extra Virgin Olive Oil Extraction Methods through a Life Cycle Thinking Approach: Challenges and Opportunities in the Elaio-Technical Sector

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