SUSTAINABLE CULTIVATION OF OLIVE TREES BY REUSING OLIVE MILL WASTES AFTER EFFECTIVE CO-COMPOSTING TREATMENT PROCESSES

All olives’ treatment processes (olives, olive oil, olive wooden residue) produce liquid and solid wastes, which are considered toxic. The treatment of these wastes by using conventional technologies (aerobic/anaerobic biological treatment, incineration, gasification ect) proved to be neither technically nor cost effective. This fact treats the olive oil production by complete cease due to the serious environmental problems caused. The proposed technology includes the detoxification of wastewater by Fenton oxidation reactions and following their utilization by biological treatment methods. The latter is achieved by the implementation of anaerobic digestion process on the oxidized wastewater and the consequent methane production and by co-composting the oxidized or/and anaerobic digested wastewater with solid wastes (olive mill wooden residue, leaves, branches ect.), leading to the production of a high quality soil conditioner. The biogas produced could be utilized for in situ thermal and electrical energy production. The two biological processes used (anaerobic digestion and composting) are ideal combined, since the anaerobic digested wastewaters are totally used in composting process, while the excess thermal energy produced by biogas utilization can accelerate the aerobic biological processes resulting in a high quality biological fertilizer. The proposed technology is effective and simple to be implemented. Wastewaters derive either from two or three phase olive mill could be treated. This technology can be implemented either in one olive mill scale or in central wastewater treatment plants. The proposed technology can not only effectively face the serious environmental problems caused by olive mill wastewater disposal, but it poses new perspectives in olive trees cultivation and olive oil and its by-products market

Optimisation of Bioethanol Production in a Potato Processing Industry

Nowadays, there is a requirement for industries to eliminate carbon from their energy mix and substitute it with greener options. This calls for investment in efforts to facilitate the scaling up of technical advancements. Because of the huge amount of waste, a life cycle strategy has been used by industries, especially the food industry, to lessen the environmental impact of their products. One of the sectors that burdens the environment with a significant amount of waste is the potato processing industrial sector. The current study focuses on the valorisation of all the potato processing waste streams (potato peels, potato tubers and slices, starch and low-quality chips) towards bioethanol production at a pilot level. After their physico-chemical characterisations, several experimental trials were performed in order to determine the optimum pretreatment and hydrolysis conditions for each waste stream. Acid hydrolysis, alkaline hydrolysis and hydrothermal pretreatment were examined when no pretreatment resulted in low ethanol yields (below 60%). The optimum results that were obtained were applied in a pilot plant of 200L to examine the upscaling factor. It was verified that upscaling by 1000 times generates comparable and, in some cases, greater results. From the integration of the results and the mass balances of a typical potato processing company, a full-scale implementation plan was also set up, where it was calculated that around 2 m3 bioethanol per week could be produced

Added-value molecules recovery and biofuels production from spent coffee grounds

Spent Coffee Grounds worldwide production is estimated at around 6 M tons only at industrial level. The abundance and the heterogeneity of this substrate make it an ideal substrate for a biorefinery approach based on the "cascade biorefinery hierarchy". Currently, the major part of spent coffee grounds is sent to incineration and landfill disposal, options which should be avoided. Instead, they could be valorised through biofuels production. All the operational parameters leading to the highest biogas (350-400L(CH4)/kg(TVS)), bioethanol (3-4%v/v) and biodiesel (over 90% of Fatty Acid Methyl Esters concentration) yields from spent coffee grounds have been discussed in this review paper. They are rich in an oil phase containing different added-value molecules (tocopherols, cafestol, kahweol along with linoleic and palmitic acids), which can be extracted and used as additives for food, cosmetic and pharmaceutical applications. Solid/liquid extraction techniques of coffee oil from spent coffee grounds such as the most common Soxhlet technique and the more innovative fluids in supercritical conditions have been discussed, with coffee oil recovery of around 5-15%w/w and 15-20%w/w, respectively. The most recent applications of the extracted coffee oil have been also presented: the added-value molecules recovery and purification after micro/ultra and nano filtrations processes and the polyhydroxyalkanoates (0.84 g/g) and biosurfactants (3.5 g/L) production. Considering the whole information, an integrated biorefinery scheme, along with the respective mass balances were proposed. The novelty of this paper lies in the integration of the state-of-the-art data, in a biorefinery concept that would allow the production of both biofuels and value-added products

Upcycled Animal Feed: Sustainable Solution to Orange Peels Waste

Currently, in an effort to increase their sustainability and reduce their carbon footprint, industries look for ways to valorise their waste instead of simply treating it. At the same time, food insecurity is increasing with alarming rates and thus solutions are sought. To this end, the main objective of this paper was to optimise an innovative valorisation strategy to turn orange juice industry by-products into high-value secondary feedstuff for animals. In this context, a valorisation strategy was designed where a saccharification step of the orange peels and an aerobic fermentation step of the liquid residue were included. Both processes were optimised via factorial deign. The saccharification process was optimised in terms of pectinolytic and cellulolytic enzymes and solid loading, whereas the aerobic fermentation method was optimised in terms of nutrients addition, the yeast to glucose ratio, and pH control. According to the optimised conditions, the final animal feedstuff should be formulated by mixing the solid residue of orange peels after the saccharification process under the optimum conditions (50 °C, 24 h, 7.5% solids loading, Pectinex 25 μL/g TS, CellicCTec3 25 μL/g TS), with the harvested yeast cultivated aerobically on orange peels hydrolysate (30 °C, 24 h, orange peels hydrolysate as sugar source, nutrients addition, yeast to glucose ratio equal to 0.02). Finally, the formulated feedstock should be dried in order to stabilise the product in terms of shelf life and feed safety. The final feedstuff presented 23.11% higher in vitro organic matter digestibility and threefold protein content