Use of olive mill wastewater compost for crop production (original) (raw)
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Reducing the Environmental Impact of Olive Mill Wastewater
American Journal of Environmental Sciences, 2009
Problem Statement: A research was needed to monitor the environmental impact of olive mill wastewater (OMW): production and relative production of olive mill waste. This was achieved by collecting data from 92 local olive mills in order to study the olive production yield, water consumption in olive washing and in oil recovery, wastewater generation relative to olive processed and oil generated, and solid waste generation. The OMW is usually discharged in the open environment, thus producing pollution to the soil surface and underground water. Approach: The progress on this problem is made by reducing the chemical oxygen demand (COD) as a major OMW pollutant. An upper flow anaerobic sludge bed (UASB) facility was constructed and operated for eight months in a progressive program operation for standardization and optimization purpose, and so to treat the waste by COD reduction. Results: The results reveal local variation in most of the investigated parameters. The olives in some area are found to contain large solid waste than other areas, resulting in lower oil yield and higher solid generation per ton of olive produced. The COD concentration was increased gradually from 5,000-30,000 mg/L and the efficiency improved significantly during the operation from 46%-84% COD removal. The organic load of OMW 27,000mg/L was reduce below 5,000 mg/L, that permits its direct discharge into municipal wastewater treatment plants. Conclusion: The implications and relevance of the results imply that OMW must be treated before discharge to the sewer system. On the other hand, the nonconformity between areas must be taken into consideration for future work.
Olive Mill Wastewater Treatment: A Recent Review
Jordanian Journal of Engineering and Chemical Industries, 2020
Olive oil-producing countries in the Mediterranean region generate a considerable amount of olive mill wastewater (OMW), contributing to a severe environmental polluting issue due to its high pollution load. This effluent is exceptionally toxic to the whole soil-air-water ecosystem, and the living organisms inhabiting it (i.e., plants, animals, aquatic organisms, microorganisms, etc.). Many researchers have assessed the efficiencies of different treatment techniques to find an environmentally friendly and economically viable solution to be generally adopted. In light of that, the present review article summarizes the state-of-the-art concerning the OMW treatment options, with their pros and cons when possible.
Desalination and Water Treatment, 2016
The Mediterranean region is the largest olive oil producer in the Word accounting for about 97% of the world oil production [1]. Improving the olive oil processing in this region is of enormous importance for the whole region as well as for each individual country [2]. The process of oil extraction generates annually about 30 million cubic meter of olive mill wastewater (OMW) [3]. The disposal of untreated OMW imposes environmental and health hazards and is considered one of the most serious
Olive mill wastewater treatment: an experimental study
Water Science and Technology, 2006
Olive oil production, one of the main agro-industries in Mediterranean countries, generates significant amounts of olive mill wastewaters (OMWs), which represent a serious environmental problem, because of their high organic load, the acidic pH and the presence of recalcitrant and toxic substances such as phenolic and lipidic compounds (up to several grams per litre). In Italy, traditional disposal on the soil is the most common way to discharge OMWs. This work is aimed at investigating the efficiency and feasibility of AOPs and biological processes for OMW treatment. Trials have been carried out on wastewaters taken from one of the largest three-phase mills of Italy, located in Quarrata (Tuscany), as well as on synthetic solutions. Ozone and Fenton's reagents applied both on OMWs and on phenolic synthetic solutions guaranteed polyphenol removal efficiency up to 95%. Aerobic biological treatment was performed in a batch reactor filled with raw OMWs (pH =4.5, T=30 °C) without bio...
Olive wastewater as an ecological fertiliser
Agronomy for sustainable …, 2006
The effects of untreated and treated olive mill wastewater on seed germination, plant growth and soil fertility were studied. Tomato (Lycopersicon esculentum), chickpea (Cicer arietinum), bean (Vicia faba), wheat (Triticum durum) and barley (Hordeum vulgare) were tested for the germination index and growth in soil irrigated by olive mill wastewater. Lepidium sativum was used as the standard species for the germination index and phytotoxicity evaluation. We measured soil properties, crop growth, herbage biomass, leaf elongation and productivity. The results show beneficial effects using treated olive mill wastewater. The treated plants showed an improvement in seed biomass, spike number, plant growth, and a similar or even better dry productivity than plants irrigated with water, e.g. Hordeum vulgare 102%, Triticum durum 105%, Cicer arietinum 101% and Vicia faba 102%. An increase in the germination index from 100% to 115% was observed. Soil organic matter, respiration and enzymatic activities were also enhanced by treated olive mill wastewater ferti-irrigation. However, even diluted 10 times, untreated olive mill wastewater inhibited the species germination, e.g. 1.2% for Hordeum vulgare and 40% for Cicer arietinum and Vicia faba, and plant growth (16-42.5%). Leaf necrosis and low productivity were observed in crops ferti-irrigated by untreated olive mill wastewater.
Strategy for olive mill wastewater treatment and reuse with a sewage plant in an arid region
Water Science & Technology, 2007
This study was conducted to evaluate the treatability of OMW (olive mill wastewater) with sewage and sewage sludge, which could supplement nutrients and microbes required for OMW treatment and reduce its possible toxicity. The amount of OMW added to an aeration tank was based on the loading difference between the designed and actual COD loads, while the amount added to anaerobic digestion for energy recovery was determined by CH4 production. The COD removal efficiencies were 70–85% for both systems. Compost of OMW with dried sewage sludge also showed a similar temperature profile without OMW addition. This strongly suggested that OMW can be treated at a sewage plant without pretreatment and the treated effluent can be reused in irrigation for an arid region.
Olive Mill Wastewater: Treatment and Valorization
Springer Water. Springer, Cham, 2023
For more than 7000 years, olive oil production and consumption have been an established tradition in the Mediterranean area. Due to its great dietary and nutritional value, the olive oil industry is quickly growing across the world. Its manufacturing takes place in two ways: press extraction (the traditional method) and the continuous three-phase decanter process. Olive oil is extracted from the fruit of the olive and mixed with water to create a paste. Water is used in some of these steps to squeeze out most of the oil from the olive. The resulting paste is then mixed to increase the percentage of available oil. Both methods produce approximately (20%) olive oil, (30%) solid waste (olive husk) and 50% olive mill wastewater. This olive mill wastewater has a low pH and contains high toxic organic loads, which makes it a major environmental issue for countries producing olive oil. This chapter discusses the various approaches used for the mitigation of wastewater contaminants produced by the olive oil industry. Recent research studies which focused on the valorization options for dealing with olive mill waste residues such as animal feed, biofuel and biogas are also discussed.
New Approaches to Olive Mill Wastes Bioremediation
Remediation of olive mill wastewater (OMW) is an important issue associated with olive-oil manufacturing, a widespread activity in the Mediterranean area. This high organic loading effluent contains water, organic acids, high-molecular-weight polyphenols such as tannins, antocyanins and catechins, which are considered to be responsible for its brownish black colour and ecotoxic properties. The composition of OMWs is highly variable with respect to each individual component, depending on the process conditions and on the agricultural specificities. Thus, different approaches are applicable concerning to OMW treatment and valorisation , considering the specificities of its production and in particular the oil extraction process. Besides there are several physical, physico-chemical, biological and combined processes to OMW detoxification, each may represent an opportunity for a specific condition. It is important to explore new possibilities that are both environmentally sustainable an...
Detrimental effects of olive mill wastewater on the composting process of agricultural wastes
Waste Management, 2006
In order to study the suitability of composting olive mill wastewater (OMW-L) by repeated applications, OMW-L was added to one mixture of lawn trimmings and olive husks as bulking agents. The composting process of this mixture was compared with another pile having 35% of olive mill wastewater sludge (OMW-S) obtained from evaporation ponds and a third, as a control, without olive mill wastewater. The repeated applications of OMW-L resulted in a sharp decrease in respiration measurements after the first 20 days of composting and showed a re-increase after 40 days following the substituting of OMW-L by water. The OMW-L addition increased the rate of water-soluble phenols in the compost and caused the appearance of a phenol fraction of high molecular-mass (510 kDa) at the end of composting. OMW-L addition also caused a clear decrease in both thermophilic bacteria and thermophilic eumycete counts. A longer persistence of phytotoxicity was observed in comparison with the other piles. However, the OMW-S produced a compost with a high degree of maturity.
Opportunities for expanding the use of wastewaters for irrigation of olives
Agricultural Water Management, 2020
Olive trees are iconic to the Mediterranean landscape and in recent times, have expanded to other regions across the globe that share similar climatic conditions. Olive oil production benefits from irrigation, but with a changing climate and uncertainty in precipitation patterns, wastewaters will likely play a larger role supplementing irrigation water requirement. However, due to their relatively poor quality, wastewaters present challenges for sustained long-term use in olive production. Wastewaters include all effluents from municipalities, agricultural drainage, animal production facilities, agricultural processing and industrial processes. This review focuses on potential opportunities and limitations of sustaining olive oil production in the Mediterranean region using wastewater of various sources. The primary challenges for using such wastewaters include concerns related to salinity, sodicity, metals and trace elements, nutrients, organics, and pathogens. Organics and plant nutrients in the effluents are typically beneficial but depend on dosages. Many studies have shown that saline wastewaters have been successfully used to irrigate olives in Greece, Israel, Italy, Jordan and Tunisia. Still, olive varieties and rootstocks have different tolerances to salinity and could respond differently and oil quality may improve or be compromised. Salts and trace elements need to be monitored in plants and soil to make sure accumulation does not continue from year to year and that soil physical conditions are not affected. Some food industries generate effluents with suitable characteristics for irrigation but one must balance the benefits (e.g. addition of nutrients), detriments (e.g. addition of salts or other limiting chemicals) and costs when determining the feasibility and practicality of reuse. Long-term accumulation of trace elements and metals will likely limit the feasibility of using industrialoriginating effluents without treatment processes that would remove the toxic constituents prior to reuse. Therefore, untreated wastewaters from the many industries have limited long-term potential for reuse at this time. Application of olive mill wastewater may be agronomically and economically beneficial, particularly as a local disposal solution, but there are concerns associated with high-concentrations of polyphenols that may be phytotoxic and toxic to soil microbial populations. With regards to human safety, risk of contamination of table olives and olive oil is very low because irrigation methods deliver water below the canopy, fruits are not picked from the ground, processing itself eliminates pathogens and the irrigation season typically ends days or weeks before the harvest (depending on the climate condition). Finally, considering physiological, nutritional and intrinsic characteristics of this species, it is clear that olive trees are appropriate candidates for the reuse of recycled wastewater as an irrigation source.