Cork Industry Research Articles

Practical approach to the evaluation of industrial wastewater treatment by the application of advanced microbiological techniques

In cork industry, the operation of boiling raw cork generates large volumes of wastewater named Cork Boiling Wastewater (CBW). The main characteristics are the low biodegradability and medium to low acute toxicity, resulting in the necessity of designing advanced biological treatments by possible conventional activated sludge adaptation. In order to evaluate the variation of bacterial population along that process, a study based on optical microscopy, plate count, DNA extraction, qPCR and massive sequencing techniques was performed. Results showed a diminution of the total and volatile solids (TSS and VSS), jointly with a decrease in DNA concentration, general bacteria (16 S) and ammonia-oxidizing bacteria (AOB). After a few hours of testing, diverse microbiological species died while others showed a possible adaptation of the biological system, accompained by a dissolved organic carbon (DOC) reduction. In addition, toxicity tests based on activated sludge showed the development of chronic toxicity through the contact time. Combination of classical and advanced microbiological techniques, such as quantitative real time Polymerase Chain Reaction (qPCR) and metagenomics, was essential to predict the variation of species during the experiment and to conclude if effective biological adaptation could be finally attained for the target complex wastewater.

Screening of Solid Waste as Filler Material for Constructed Wetlands

The reuse of solid waste can contribute to reducing Earth’s resource depletion, directly through use in the original production processes or by valorisation in alternative applications. In the present work, ten solid wastes were evaluated as candidates for filling material in constructed wetlands (CWs). For that purpose, physical characterization, leaching and adsorption tests were conducted. Limestone fragments and brick fragments resulting from construction activities, coal slags resulting from power plants, snail shells resulting from the food and catering industry, and cork granulates resulting from the cork industry have potential for use as CW fillers. These five materials have adequate physical properties and some capacity to adsorb phosphorous and organic compounds from wastewater. On the other hand, crushed eggshells resulting from egg farms, dealcoholized grape pomaces resulting from alcohol distilleries, olive seeds waste from olive-oil mills, and pine bark fragments and wood pellets resulting from forestry cleaning activities, wood mills and pulp mills did not demonstrate sufficient potential to be used as CW fillers, either because they have very low adsorption capacities or leach compounds in contact with water, or because they have less adequate physical properties. None of the tested solid wastes showed the ability to adsorb nitrogen compounds. Although the five selected materials do not present a special capability for adsorption of nitrogen, phosphorous and organic compounds, they can all be valued as CW fillers, representing a way to reduce the amount of solid waste sent to landfills.

Gasification of Cork Wastes in a Fluidized Bed Reactor

Biomass gasification has been identified as an option for energetic valorisation of organic wastes. This work aimed to study the gasification of cork industry wastes using a semi-batch fluidized bed reactor. The experimental tests were performed using air as oxidizing agent and sand particles as bed material. The heating was performed with an electrical resistance of 3 kW. The effect of biomass load (2–5.6 g), and bed temperature (780–900 °C) on gasification performance was evaluated using an air flow rate of 0.092 g/s. Samples of producer gas were analysed by a gas chromatograph fitted with a thermal conductivity detector. The detected and quantified compounds on producer gas were H2, CO, CH4 and CO2. Temperature and mass load had a predominant role in gasification performance and all gasification parameters increased with the temperature rise. The increase of mass resulted in a decrease of carbon conversion efficiency, cold gas efficiency and dry gas yield. Best results were obtained with mass load at a range of of 2–4 g, working at 850 °C. The results showed that cork particles are a sustainable raw material for gasification processes.

Civilizing through Cork: Conservationism and la Mission Civilisatrice in French Colonial Algeria

The French occupation of Algeria began in 1830 and lasted over 130 years. In the decades following the initial conquest, French imperial agents emphasized the colonial enterprise's social and environmental aims. Claiming that centuries of misuse and abuse had decimated Algeria's environment, they presented the colonial project as an opportunity to adapt indigenous inhabitants to more sustainable uses of land. This civilizing mission helped elevate Algerian cork production into one of the colony's most profitable industries. In the process, it had a detrimental impact on Algerian forests and mobile pastoralists. This article uses cork as a case study to explore the meaning of the French civilizing ethic and its role in France's occupation of Algeria. It makes three main claims. First, it argues that the nineteenth-century French civilizing mission combined social and environmental values, perceptions, and concerns. Second, it demonstrates that this ethic was a guiding factor in the French conquest of Algeria. Finally, it posits that the Algerian cork industry succeeded in part because it purported to embody the French colonial mission's social and environmental ideals.

Applying SMED methodology in cork stoppers production

Organizations are increasingly required to have a high level of quality and flexibility in production. In order to remain in the market and become competitive, the working methods practiced must be reliable and efficient. The present project sought the improvement of an equipment of the cork industry by introducing a variation, through the application of Lean methods. The equipment under study performs the union of a cork stopper to a capsule, which is done by gluing it with hot-melt glue. The amount of production makes the changeover activity a regular process. The method followed in this work was the study and collection of information on the Lean production philosophy and its application in the cork industry. The working conditions of the assembly machine were also analyzed in order to find opportunities for improvement. Thus, the tool used was the Value Stream Mapping (VSM) technique in order to acknowledge the processes that really add value to the product. The SMED (Single Minute of Exchange of Die) methodology was applied in a way to reduce the downtime caused by tool changes, and a reduction of 43% in total changeover time was obtained. It was also created an A3 model to monitor the entire development of the SMED project, Finally, the OEE (Overall Equipment Efficiency) calculation was implemented as an indicator of overall equipment efficiency, in order to improve the monitoring of possible deviations during production. The feedback also proves that lean tools are a powerful method to get solid returns without large investments.

A novel study on the influence of cork waste residue on metakaolin-zeolite based geopolymers

The effect of industrial waste from the cork industry on the strength and adsorption properties of zeolite-metakaolin based geopolymers has been studied. Cork residue 20% by weight was added to geopolymers that contained 0%, 25%, 50%, 75% replacement of metakaolin by zeolite in the structure. The SiO2/Al2O3 and Na2O/Al2O3 molar ratios were kept at 1 to reduce the environmental impact of sodium silicate and sodium hydroxide to the minimum. The compressive strength evolution after 1, 14 and 28days in water and the heavy metals (Cd2+, Cr3+, Cu2+, Pb2+, and Zn2+) adsorption of the geopolymers were determined. It was found that addition of zeolite and cork residue in minor amounts concurrently aided in increasing the compressive strength of geopolymers. The adsorption properties, however, were dominated by the presence of cork residue and metakaolin which resulted in increasing adsorption of all heavy metal cations with increasing metakaolin in the structure. The adsorption was well fitted by the Langmuir model with R2>0.98 and the trend of adsorption was found to be Pb2+>Cd2+>Cu2+, Zn2+>Cr3+. The significant improvement in compressive strength, as well as adsorption capacity observed with the addition of cork waste residue, connotes that it can be efficient as filler in geopolymers.

Recovery of phenolic compounds from multi-component solution by a synthesized activated carbon using resorcinol and formaldehyde.

The adsorption of four phenolic compounds (gallic acid, protocatechuic acid, vanillic acid and syringic acid) is investigated using a synthesized mesoporous carbon on both single and multi-component synthetic solutions. Some correlation of the adsorption capacity of the carbon and the nature of adsorbate could be made, except for gallic acid whose concentration decrease seems to be not exclusively due to adsorption but also to polymerization reaction. In the multi-component mixture, negative effects in the adsorption capacity are observed probably due to competition for the active centers of the adsorbent surface. In desorption studies, ethanol presents better performance than water and acetonitrile. Vanillic acid is the compound with the higher adsorption and interestingly it is then possible to desorb a relatively high amount of it from the adsorbent, which may represent a possibility for a selective recovery of vanillic acid. These results present a potential way to treat the wastewater from the cork industry.

Influence of temperature on the gasification of cork wastes

This work aimed to study the gasification of cork industry residues using a semi-batch fluidized bed reactor. The experimental tests were performed using air as oxidizing agent and sand particles as bed material. The effect of bed temperature (780 – 900 ºC) on gasification performance was evaluated. Samples of producer gas were analysed, by a gas chromatograph, allowing the quantification of CO, CO2, H2, CH4, O2 and N2. Temperature had an important role in gasification performance and all gasification parameters showed an increase with the temperature rise up to 850 ºC.

Aspergillus spp. prevalence in different Portuguese occupational environments: What is the real scenario in high load settings?

ABSTRACTThe genus Aspergillus is one of the most prevalent regarding fungi in several highly contaminated occupational environments. The goal of the current study was to assess the prevalence of Aspergillus spp. in different settings, focusing on those where a higher load of fungal contamination is expected according to the European Agency for Safety and Health at Work. A specific protocol to ensure a more accurate assessment of the exposure to Aspergillus spp. is proposed aimed at allowing a detailed risk characterization and management. Two wastewater treatment plants, one wastewater elevation plant, four waste treatment plants, three cork industries, five slaughter houses, four feed industries, one poultry pavilion, and two swineries, all located in the outskirts of Lisbon, were assessed. In total, 125 air samples and 125 surface samples were collected and analysed by culture-based methods. Real-time polymerase chain reaction was performed to detect fungal presence in 100 samples, targeting the Aspergillus sections Circumdati, Flavi, and Fumigati. The highest prevalence of Aspergillus spp. was found in wastewater treatment plants (69.3%; 31.1%), waste treatment plants (34.8%; 73.6%), and poultry feed industry (6.3%; 26.1%), in air and surfaces, respectively. Aspergillus spp. was also prevalent in cork industry (0.9%; 23.4%), slaughter houses (1.6%; 17.7%), and swineries (7.4%; 9.5%), in air and surfaces, respectively. The Aspergillus sections more prevalent in the air and surfaces of all the assessed settings were the Nigri section (47.46%; 44.71%, respectively), followed by Fumigati (22.28%; 27.97%, respectively) and Flavi (10.78%; 11.45%, respectively) sections. Aspergillus section Fumigati was successfully amplified by qPCR in 18 sampling sites where the presence of this fungal species had not been identified by conventional methods. It should be highlighted that the occupational exposure burden is due not only to the Aspergillus load, but also to the toxigenic potential of this genus. Based on our results, a protocol relied in the application of conventional and molecular methods in parallel is herein suggested aimed at allowing a better risk characterization and management.

Cork ‐ a natural material for linalool controlled release

AbstractControlled release of aromatic mixtures to the atmosphere is a requirement for scented systems for indoor applications. The product must smell nice, but also be able to last, slowly releasing the perfume over time. Several adsorption materials have been used, for this purpose. In this study, cork was investigated as a potential perfume adsorbent for application in scented drawer sachets and equivalent products. Cork was selected due to its adsorption properties and because it is a natural, renewable, sustainable material. Granulated cork is a significant by‐product in cork industries and it was chosen for adsorption in this work. Linalool, an enantiomeric monoterpene alcohol and one of the main components of several essential oils, was selected as the model compound for adsorption studies.Activated carbon (AC) was used as the reference material. The sorption of linalool to granulated cork and AC was evaluated by HS‐SPME‐GC‐FID. The linalool isotherm on cork was shown to follow a Brunauer‐Deming‐Deming and Teller, Type IV model. The isotherm data on AC can be adjusted to Langmuir and Freundlich models. A maximum adsorption capacity of 3.9x103μg/g was achieved for AC. Desorption studies were performed. Linalool was still released from granulated cork after three equilibrium stages of desorption, whereas only two desorption values were obtained for AC from the equilibrium with highest linalool concentration. Thus, AC demonstrated good adsorption but not good desorption properties. Sorption and desorption studies of linalool from granulated cork, showed that granulated cork could be an excellent material allowing controlled release of the aroma.

Intervencionismo en los sectores exportadores tradicionales durante el Primer Franquismo: el caso del corcho

Junta de Extremadura. Ayudas para la realizacion de actividades de investigacion y desarrollo tecnologico, de divulgacion y de transferencia de conocimiento por los Grupos de Investigacion de Extremadura (GR15182)

Cluster and business performance: Historical evidence from the Portuguese cork industry

This paper analyses the relative performance of clustered and non-clustered companies during the different phases of the cluster life cycle. It starts by explaining the location of most of the Portuguese cork manufacturing companies in Santa Maria da Feira, a small county in the north of the country, whereas the bulk of cork is produced in the South. The historical roots of the Feira cluster are examined, as well as the identification of its life cycle phases. The performance of clustered and non-clustered companies is compared using labour productivity data over a long time span of several decades. This exercise illustrates the crucial importance of history for the understanding of cluster dynamics, as well as many other (evolutionary) economic phenomena.

Recycling the Cork Powder in a PVC-Based Composite Material: Combined Effect on Physico-Mechanical and Thermal Properties

Abstract A large amount of cork powder (CP) produced by cork industry ended up in landfills, they are the result of the crushing of natural floor (bark) cork oak, hence the need to recycle these wastes to prevent environmental problems. To this end, the work is to combine the powdered cork recovered with a thermoplastic material to provide a cork based composite (CPC) having physico-mechanical characteristics and thermal very interesting. Several formulations of composite materials based on PVC (as matrix), cork powder (as a charge) and a PVC-g-MA coupling agent, have been the subject of experimental study to evaluate the physical-mechanical and thermal properties. To investigate the combined effect of cork powder and PVC-g-MA on composite properties, the samples were manufactured by varying the content of PC (30 %, 40 % and 50 %) with two PVC-g-MA concentrations. Improving the stability of PVC which is accentuated in the presence of the coupling agent. In addition, it was found that the incorporation of the coupling agent has enabled the elimination of the adverse effect of cork powder, improving the tensile strength. The composite obtained in this study yielded some promising properties, even if building strategies to achieve greater strength and rigidity could beings needed for specific applications.

A carbon footprint simulation model for the cork oak sector

In the present study, a simulation model for the calculation of the carbon footprint of the cork oak sector (CCFM) is developed for the first time. A life cycle approach is adopted including the forest management, manufacturing, use and end-of-life stages. CCFM allows the user to insert the cork type used as raw material and its respective quantity and the distances in-between the various stages. The user can choose among different end-of-life destination options for the used cork products. The option of inserting different inputs, allows the use of the present simulation model for different cork oak systems, in different countries and with different conditions. CCFM allows the identification of the stages and products with the greatest carbon footprint and thus, a better management of the sector from an environmental perspective. The Portuguese cork oak sector is used as an application example of the model. The results obtained showed that the agglomeration industry is the hotspot for the carbon footprint of the cork sector mainly due to the production of the resins that are mixed with the cork granules for the production of agglomerated cork products. The consideration of the biogenic carbon emissions and sequestration of carbon at the forest in the carbon footprint, resulted to a great decrease of the sector's carbon footprint. Future actions for improvement are suggested in order to decrease the carbon footprint of the entire cork sector. It was found that by decreasing by 10% the emission factor of the agglomeration and transformation industries, substituting the transport trucks by more recent ones and by decreasing by 10% the cork products reaching the landfilling end-of-life destinations (while increasing the quantities reaching incineration and recycling), a decrease of the total CF (excluding the biogenic emissions and sequestration) of the entire cork industry by 10% can be achieved.

Analysis of surfaces for characterization of fungal burden - Does it matter?

Mycological contamination of occupational environments can be a result of fungal spores' dispersion in the air and on surfaces. Therefore, it is very important to assess it in both types of the samples. In the present study we assessed fungal contamination in the air and in the surface samples to show relevance of surfaces sampling in complementing the results obtained in the air samples. In total, 42 settings were assessed by the analysis of air and surfaces samples. The settings were divided into settings with a high fungal load (7 poultry farms and 7 pig farms, 3 cork industries, 3 waste management plants, 2 wastewater treatment plants and 1 horse stable) and a low fungal load (10 hospital canteens, 8 college canteens and 1 maternity hospital). In addition to culture-based methods, molecular tools were also applied to detect fungal burden in the settings with a higher fungal load. From the 218 sampling sites, 140 (64.2%) presented different species in the examined surfaces when compared with the species identified in the air. A positive association in the high fungal load settings was found between the presence of different species in the air and surfaces. Wastewater treatment plants constituted the setting with the highest number of different species between the air and surface. We observed that surfaces sampling and application of molecular tools showed the same efficacy of species detection in high fungal load settings, corroborating the fact that surface sampling is crucial for a correct and complete analysis of occupational scenarios.

Uncorking knowledge- purposeful spillovers as a strategic tool for capability enhancement in the cork industry

There is a growing body of research linking knowledge spillovers to strategic entrepreneurship in multiple contexts, yet the existence of purposeful spillovers has been largely ignored. This study analyses the value-accretive potential of knowledge spillover strategies, where a selected body of knowledge is purposefully and strategically disclosed to competitors. The cork industry provides the empirical context, with the many small firms possessing limited innovation capabilities in an industry under threat from rival alternative technologies. The successful fight-back against the onslaught on cork by synthetic and screwcap closures is led by the Portuguese company Corticeira Amorim, the world’s largest stopper manufacturer, whose knowhow then selectively spills-over to the rest of the industry. This multiple-case study involving 14 firms, unfolds in the context of two layers of underlying tensions. By exploring why and how knowledge selectively spillovers across filters from the industry leader to others, and knowledge revealing within small firms, the study contributes to extant literature by extending to the phenomenon of selected and purposeful spillover in the context of capability enhancement.

The SHORT-ROOT-like gene PtSHR2B is involved in Populus phellogen activity.

SHORT-ROOT (SHR) is a GRAS transcription factor first characterized for its role in the specification of the stem cell niche and radial patterning in Arabidopsis thaliana (At) roots. Three SHR-like genes have been identified in Populus trichocarpa (Pt). PtSHR1 shares high similarity with AtSHR over the entire length of the coding sequence. The two other Populus SHR-like genes, PtSHR2A and PtSHR2B, are shorter in their 5' ends when compared with AtSHR. Unlike PtSHR1, that is expressed throughout the cambial zone of greenhouse-grown Populus trees, PtSHR2Bprom:uidA expression was detected in the phellogen. Additionally, PtSHR1 and PtSHR2B expression patterns markedly differ in the shoot apex and roots of in vitro plants. Transgenic hybrid aspen expressing PtSHR2B under the 35S constitutive promoter showed overall reduced tree growth while the proportion of bark increased relative to the wood. Reverse transcription-quantitative PCR (RT-qPCR) revealed increased transcript levels of cytokinin metabolism and response-related genes in the transgenic plants consistent with an increase of total cytokinin levels. This was confirmed by cytokinin quantification by LC-MS/MS. Our results indicate that PtSHR2B appears to function in the phellogen and therefore in the regulation of phellem and periderm formation, possibly acting through modulation of cytokinin homeostasis. Furthermore, this work points to a functional diversification of SHR after the divergence of the Populus and Arabidopsis lineages. This finding may contribute to selection and breeding strategies of cork oak in which, unlike Populus, the phellogen is active throughout the entire tree lifespan, being at the basis of a highly profitable cork industry.

Assessment of exposure to the Penicillium glabrum complex in cork industry using complementing methods.

Cork oak is the second most dominant forest species in Portugal and makes this country the world leader in cork export. Occupational exposure to Chrysonilia sitophila and the Penicillium glabrum complex in cork industry is common, and the latter fungus is associated with suberosis. However, as conventional methods seem to underestimate its presence in occupational environments, the aim of our study was to see whether information obtained by polymerase chain reaction (PCR), a molecular-based method, can complement conventional findings and give a better insight into occupational exposure of cork industry workers. We assessed fungal contamination with the P. glabrum complex in three cork manufacturing plants in the outskirts of Lisbon using both conventional and molecular methods. Conventional culturing failed to detect the fungus at six sampling sites in which PCR did detect it. This confirms our assumption that the use of complementing methods can provide information for a more accurate assessment of occupational exposure to the P. glabrum complex in cork industry.

Integrating Environmental Attributes into Marketing Strategies of Wine Producers

Due to the fast technological advancement, pressures regarding environmental sustainability and social responsibility have become inseparable part of every industry. Wine industry, which is based on the agricultural products has a direct impact on the environment and consequently is involved in the general trend and increased concern of the environmental sustainability. Together with the high quality, contemporary and future consumers will expect the wine-growing and producing practices to be environmentally sustainable. This trend has the direct influence on the obvious shift of wine producers from corks to alternative twists as the top closures of the bottle. Occurring without actual tree removal, cork harvesting retains wildlife habitat in a uniquely biologically diverse landscape. Consequently important notion exists that fate of many species is tied to that of cork industry. This trend creates interesting relationship among cost reduction, environmental ustainability and customer perception and segmentation. More specifically, while alternative twist tops, other than corks, increase the ease of consuming the product, it decreases the customers’ perception of oldness, which represents an important aspect of the wine consumers purchasing behaviour. This indicates the necessity of careful analyses of the different segments of the market regarding the preferences of ease of usage or age of wines keeping in mind the environmental sustainability. Consequentlythe main focus will be made on presenting the findings, which will demonstrate the interesting correlation of above mentioned aspects of viti/viniculture, followed by the recommendations on proper integration of the environmental attributes in overall marketing strategies of wine producers, as the means of motivation for maintaining environmental sustainability.

Cork waste in cement based materials

Abstract Cork is a natural material that has always been associated to mankind having huge potential and many uses. The cork industry worldwide consumes more than 280,000 t of cork a year. However, about 20% to 30% of the raw cork received at the processing units is rejected, mainly as cork dust. Finding useful applications for the rejected cork may have important economic and environmental implications. Trying to combine the advanced technology of self-compacting concrete and use of this waste from the cork industry, this study concerns the possibility of using cork powder as a substitute for fines in mixtures of self-compacting concrete. An experimental program was carried out to assess the behavior of this material in the mixture and define properties in terms of strength and durability of self-compacting concrete containing cork powder. It was found that it is possible to use an abundant waste material from the cork industry, cork powder, as fines in Self Compacting Concrete resulting in a good strength level (C 30/37) and suitable durability for common applications.