Oleico+ project : olive mill wastes and the sustainability of the olive oil industry in Europe

Every year more than 15 millions tones of olive mill wastes (OMW) are generated in the EU. Those wastes consist in vegetation waters, effluents from olive oil, washing, leaves and other solids coming from wet pomaces from two phase extraction systems. Each of these residues presents different challenges, and is sometimes covered by different legal frameworks at European and National level. The Oleico+ project (LIFE07INF/IT/438), brought together four European Institutions from olive oil producing Countries, Greece, Italy, Spain and Portugal, to seek and select a set of environmental friendly technologies for the remediation or valorization of OMW, and to raise the awareness of olive oil stakeholders for an environmental sustainable olive mill waste management. The OMW management is becoming a critical issue for the sustainability of olive oil industry, because of the increasing quantities generated, the public environmental awareness and stricter environmental laws. Challenges posed by the OMW management are as diverse as the context of olive production itself. In all cases olive mill owners are in the top of an economic sector of major social and environmental importance in some of the more vulnerable Mediterranean regions of Europe, in an environment of depressed olive oil prices and a several of legal constrains and regulations. In this paper we examine the different contexts of OMW generation and management, their respective waste-streams and legislative frameworks. The work will also compare the situation across the four Member States, and presents the different technologies selected for the “Awareness Raising Campaign for the Treatment and Valorization of Olive Mill Wastes” now occurring in all Member Sta

Oleico+ sustainability in the olive mill waste management

Olive oil production generates olive mill wastes estimated at 2.5 million tonnes. More than 80% of olive mill wastes consist in water. Olive mill wastewater (OMW) has environmental impacts due to its high organic load and contents in phenols, lipids and organic acids. The project Oleico +, supported by the European Program LIFE, brought together 4 Institutions from 4 European Member States to seek and select a set of environmental friendly technologies for the remediation or valorization of olive mill wastes, and to raise the awareness of olive oil stakeholders for an environmental sustainable olive mill waste management. The OLEICO + project selected eight technologies to manage olive mill wastes that may be applied to different olive mill systems and amounts of waste generated. This selection was performed with a point to grid classification of technologies sustainability and status. To access eco-sustainability several parameters were accounted, including carbon dioxide emissions, landscape impacts and bead smells. Eleven technologies were selected out of 28 inventoried. Specifically five of these technologies deal with OMW and its detoxification, and four of them produce reusable water for irrigation. Other three technologies are focused in the energetic and or agronomic valorization of olive mill wastes. Some of these technologies present positive net income values, a many of them do not require specialized workforce, but the small dimension of olive mills make the management of olive mill wastes a challenge for the industr

Integrated process for bioenergy production and water recycling in the dairy industry:Selection of Kluyveromyces strains for direct conversion of concentrated lactose-rich streams into bioethanol

Dairy industries have a high environmental impact, with very high energy and water consumption and polluting effluents. To increase the sustainability of these industries it is urgent to implement technologies for wastewater treatment allowing water recycling and energy savings. In this study, dairy wastewater was processed by ultrafiltration and nanofiltration or ultrafiltration and reverse osmosis (UF/RO) and retentates from the second membrane separation processes were assessed for bioenergy production. Lactose-fermenting yeasts were tested in direct conversion of the retentates (lactose-rich streams) into bioethanol. Two Kluyveromyces strains efficiently fermented all the lactose, with ethanol yields higher than 90% (>0.47 g/g yield). Under severe oxygen-limiting conditions, the K. marxianus PYCC 3286 strain reached 70 g/L of ethanol, which is compatible with energy-efficient distillation processes. In turn, the RO permeate is suitable for recycling into the cleaning process. The proposed integrated process, using UF/RO membrane technology, could allow water recycling (RO permeate) and bioenergy production (from RO retentate) for a more sustainable dairy industry

Biostimulant and biopesticide potential of microalgae growing in piggery wastewater

ABSTRACT: Pig farming generates highly polluting wastewaters which entail serious environmental issues when not adequately managed. Microalgae systems can be promising for cost, energy and environment-efficient treatment of piggery wastewater (PWW). Aside from clean water, the produced biomass can be used as biostimulants and biopesticides contributing to a more sustainable agriculture. Three microalgae (Tetradesmus obliquus, Chlorella protothecoides, Chlorella vulgaris) and one cyanobacterium (Synechocystis sp.) were selected after a preliminary screening in diluted wastewater (1:20) to treat PWW. The nutrient removals were 62-79% for COD (chemical oxygen demand), 84-92% for TKN (total Kjeldahl nitrogen), 79-92% for NH4+ and over 96% for PO43−. T. obliquus and C. protothecoides were the most efficient ones. After treating PWW, the produced biomass, at 0.5 g L−1, was assessed as a biostimulant for seed germination, root/shoot growth, and pigment content for tomato, watercress, cucumber, soybean, wheat, and barley seeds. We observed an overall increase on germination index (GI) of microalgae-treated seeds, owing to the development of longer roots, especially in T. obliquus and C. vulgaris treatments. The microalgae treatments were especially effective in cucumber seeds (75-138% GI increase). The biopesticide activity against Fusarium oxysporum was also evaluated at 1, 2.5 and 5 g L−1 of microalgae culture. Except for Synechocystis sp., all the microalgae tested inhibited the fungus growth, with T. obliquus and C. vulgaris achieving inhibitions above 40% for all concentrations.info:eu-repo/semantics/publishedVersio

Ethanol production from enzymatically pretreated wheat straw

Lignocellulosic biomass can be utilized to produce ethanol, a promising alternative energy source for the limited crude oil. Wheat straw is an abundant agricultural residue which can be used as lignocellulosic raw material for bioconversion. There are mainly two processes involved in the bioconversion: hydrolysis of cellulose in the lignocellulosic biomass to produce reducing sugars, and fermentation of the sugars to ethanol. The current study involved the optimization of enzymatic hydrolysis of a wheat straw pretreated by acid hydrolysis, using a mixture of commercial cellulases: celluclast 1.5L + Novozym 188, with further fermentation of the hydrolisate’ sugar content by three ethanologenic strains, namely two yeast of Saccharomyces cerevisiae (strains F and K) and a bacterial strain, Zymomonas mobilis (strain CP4). The fermentation assays, using undiluted hydrolisate with or without nutrient supplements, were monitored by the evaluation of glucose and ethanol yields. In the assays using no supplemented hydrolisate the results obtained for the two yeasts strains F and K, and Zymomonas mobilis were 74%, 79% and 58% of ethanol yield, respectively. However, when the hydrolisate was supplemented the fermentation results showed a better bioconversion process by the Z. mobilis, reaching 98% ethanol yield while the two strains of S. cerevisiae used maintained their behaviour. So, the fermentation results showed the necessity of the addition of nutrients for a good bioconversion process by the Z. mobilis, resulting in better ethanol yield than S. cerevisiae strains (F and K) from WSP hydrolisate

Microalgae for urban wastewater treatment and fermentative biohydrogen production

Concerns about climate changes and global water crisis are increasing, considering the low freshwater resources, pollution, and changes in the hydrological cycle. Therefore, water is a precious scarce resource being crucial to develop wastewater treatment and recovery processes to improve water resources management. On the other hand, the problematic of fossil fuels leads to its replacement by biofuels. Thus there are studies [1] to combine wastewater treatment with microalgal biomass as 3rd generation biofuel sources. This study pretends to apply the biorefinery concept to an innovative photobioreactor (PBR) to treat wastewater with microalgae and later valorise the biomass by producing biohydrogen. It is intended to reduce CO2, phosphorus, nitrogen, ammonium and other pollutants presents in wastewater, according EC targets, since microalgae consume the nutrients for growth thus removing them from the wastewater. Within the WW-SIP Life project, a new type of PBR for urban waste water treatment plant (UWWTP) effluents has been designed and will be scaled up. The tubular vertical PBR prototype (150 L) placed outdoor has an air compressor to perform agitation, a membrane module to permeate the treated water and a settler to concentrate the biomass. The results will be used to scale up a PBR of 1500 L. The PBR was fed with primary effluent from Águas da Figueira (PT) UWWTP and inoculated with Chlorella vulgaris, Scenedesmus obliquus and a consortium of microalgae (Consortium C) isolated from the wastewater. The PBR was operated in fed-batch mode and the culture parameters (e.g. pH, air-bubbling, recirculation flow) were optimized. The highest productivity was attained by C. vulgaris (2.4 gL-1day-1) and efficient nutrient removal (>75%) was observed for all algae. The microalgal biomass was then submitted to a nutritional stress for sugar and oil accumulation. Furthermore, the potential of the biomass as substrate for biofuel (bioH2) production by anaerobic fermentation in mesophilic conditions (T=30ºC) was evaluated. Batch trials were conducted in encapsulated glass serum bottles using 2.5 g/L alga and 10% (v/v) of a strain of the bacteria Enterobacter aerogenes. Fermentation kinetics were monitored by biogas analysis with GC-TCD showing that bioH2 production stabilized after around 6h. The specific production was around 45 mL H2/galga. This integrated wastewater treatment/biofuel production approach seems to be promising. In the future the production of other biofuel/biomaterials/added-value compounds will also be considered using microalgae grown in this membrane-based PBR

Kinetics of a packed-bed bacth reactor for the treatment of olive oil wastewaters from a Portuguese mill

Olive oil production is a traditional agricultural industry in Mediterranean countries and Portugal is one of the ten major producers. This industry generates an effluent, olive mill wastewater. This effluent does not undergo any treatment and is usually stored in evaporation lagoons or spread on the land. This can have a negative impact in the environment since this effluent has a high level of organic matter leading to a high chemical oxygen demand. In addition it has also a high content of polyphenols that contributes to the ecotoxicity of this effluent.Different techniques for the treatment of these wastewaters have been studied. In this work a 60 litre vessel was filled with a packaging of plastic material consisting of a cubic geometry (Biological Carrier Media from Rauschert). The non-inoculated reactor was filled with effluent from an olive mill farm (from Alfândega da Fé, Trás-os-Montes) and the effluent was re-circulated daily for homogeneity. COD, colour, nitrogen, solids and phosphorous were measured to follow the evolution of the system. Microbial composition and polyphenols were also evaluated. As an indicator of the microbial activity in the reactor, lipase activities were measured. Ecotoxicity tests were carried out to follow the detoxification capacity of the system as well as its potential for using in the treatment of this type of agroindustrial effluent

Olive Mill wastewater bioremediation towards detoxification

Olive oil production is a traditional agricultural industry in Mediterranean countries and Portugal is one of the ten major producers. This industry generates an effluent, olive mill wastewater (OMW), which does not undergo any treatment and, usually, is stored in evaporation lagoons or spread on the land. Disposal of olive oil mill wastewaters is a serious environmental problem due to its high organic loading, presence of polyphenols and tannins, high content in suspended solids and acidity, which contributes to its ecotoxicity. In this work it was intended to study the biodegradation of OMW by microrganisms naturally present in these wastewaters. Thus, an aerobic biological treatment system: a packed-bed batch reactor was applied to a OMW from a mill on northern of Portugal, exploring its autochthon microbial population as inoculum. The biodegradation ability of OMW by microrganisms naturally present in these wastewaters was assessed, by following the evolution of the process and monitoring several of its physico-chemical parameters. Furthermore, an ecotoxicological evaluation, using chronic toxicity tests (Pseudomonas putida growth inhibition test and Vibrio fischeri growth inhibition test), was performed to follow the detoxification capacity of the system as well as its potential to be used in the treatment of this type of agroindustrial effluent

Impact of high-pressure homogenization on the cell integrity of Tetradesmus obliquus and seed germination

ABSTRACT: Microalgae have almost unlimited applications due to their versatility and robustness to grow in different environmental conditions, their biodiversity and variety of valuable bioactive compounds. Wastewater can be used as a low-cost and readily available medium for microalgae, while the latter removes the pollutants to produce clean water. Nevertheless, since the most valuable metabolites are mainly located inside the microalga cell, their release implies rupturing the cell wall. In this study, Tetradesmus obliquus grown in 5% piggery effluent was disrupted using high-pressure homogenization (HPH). Effects of HPH pressure (100, 300, and 600 bar) and cycles (1, 2 and 3) were tested on the membrane integrity and evaluated using flow cytometry and microscopy. In addition, wheat seed germination trials were carried out using the biomass at different conditions. Increased HPH pressure or number of cycles led to more cell disruption (75% at 600 bar and 3 cycles). However, the highest increase in wheat germination and growth (40-45%) was observed at the lowest pressure (100 bar), where only 46% of the microalga cells were permeabilised, but not disrupted. Non-treated T. obliquus cultures also revealed an enhancing effect on root and shoot length (up to 40%). The filtrate of the initial culture also promoted shoot development compared to water (21%), reinforcing the full use of all the process fractions. Thus, piggery wastewater can be used to produce microalgae biomass, and mild HPH conditions can promote cell permeabilization to release sufficient amounts of bioactive compounds with the ability to enhance plant germination and growth, converting an economic and environmental concern into environmentally sustainable applications.info:eu-repo/semantics/publishedVersio