Microbial fuel cell (MFC) has the potential to become a promising sustainable technology of wastewater treatment. Usually, the investigations on MFCs are aimed at maximized power production in the ...system. In this article, we focused on the optimization of wood industry wastewater treatment in MFC, in combination with municipal wastewater as a source of microorganisms. We investigated the influence of different external resistance (2000 Ω, 1000 Ω, 500 Ω, and 100 Ω) on power density and wastewater treatment efficiency (chemical oxygen demand (COD) removal) in 1-month MFC operation time. We found that the highest COD removal was for MFCs under R = 1000 Ω after 22 days of MFC operation, while the highest current density was obtained for the lowest applied resistance. The results imply that wastewater treatment parameters such as resistance and time of MFC operation should be a subject of optimization for each specific type of wastewater used, in order to maximize either wastewater treatment efficiency or power production in MFC. Thus, optimization of power production and COD removal efficiency in MFCs need to be run separately as different resistances are required for maximizing these two parameters. When COD removal efficiency is a subject of optimization, there is no universal value of external resistance, but it should be set to the specific wastewater characteristics.
Experiments were carried out to test the capacity for a laboratory-scale biofilter operated at an elevated temperature level (∼50°C) to remove an air stream containing β-caryophyllene, a naturally ...occurring sesquiterpene of environmental concern emitted from wood-related industrial facilities. A water jacket was used to maintain high temperatures in a laboratory-scale biofilter. Inocula, pollutant loading and nutrient supply rate effects were evaluated over 84 days of biofilter operation. The start-up process took over two months when citrus peels were used as inocula while a relatively short start-up period was achieved after introducing forest compost products. While using a sparged-gas bioreactor to cultivate an enrichment culture for 97 days, removal efficiencies in excess of 80% were observed after 18 days. At empty bed contact times of 50 s and at a pollutant loading rate of 3.05 mg C/L/hr, removal efficiency levels reached 90% and the elimination capacity level reached 2.29 mg C/L/hr, corresponding to an elimination capacity of 2.60 mg β-caryophyllene/L/hr. Collectively, these results demonstrate that β-caryophyllene can be successfully removed from contaminated air using a biofilter operated at a high temperature (∼50°C), expanding the temperature range within which biofilters are known to biodegrade sesquiterpenes.
The consumption of wood pellets grew rapidly during the last decade. In this paper we compare the development of the production factors for wood pellet markets in Finland, Germany, Sweden, Norway and ...the US; we analyze how domestic market prices for pellet production factors as well as domestic market prices for pellets vary among the countries. The analyses are based on two model plants. The first represents common technologies for small scale pellet production based on dry residues from sawnwood production, while the second represents large scale production based on a blend of dry and wet materials. The results show how differences in costs of feedstock, energy and labor affect the profitability of pellet production and hence the development of pellet production in the analyzed countries. Pellet producers in the US have lower feedstock costs than producers in the analyzed European countries. The economic sustainability for European pellet producers depends to a large extent on their domestic markets as internationally traded pellets are priced lower than their production costs. Future pellet production will, to a greater extent, be based on wet feedstock such as roundwood and wet sawdust. These feedstocks are also demanded by wood-based industries (pulp and paper, particle- and fiber-board) as well as for traditional fuelwood. The transition from smaller pellet plants using dry feedstock to larger plants using wet feedstock in future pellet production, can be expected to follow comparative advantages regarding feedstock and energy costs, but also with respect to economies of scale.
The detection of defects in wood is valuable for promoting the efficient exploitation of wood. So it is significant to further increase the accuracy of the detection of wood defects and enhance the ...real-time detection. In this paper, the YOLOv5 convolutional neural network is applied to wood defects detection, and the model is modified for both the YOLOv5n and YOLOv5m scales. The SimAM attention model was first incorporated into the network, and the learning rate decay strategy was replaced with CosLR, with Ghost convolution employed to minimize the model parameters. Finally, the modified network was tested for five types of wood defects, including live-knot, resin, dead-knot, knot-with-crack, and crack. It is demonstrated that the improvements resulted in a 1.5% increase in mAP 0.5:0.95 for YOLOv5n-C3Ghost and a 1.6% increase in mAP 0.5:0.95 for YOLOv5m-C3Ghost. In addition, there is a 51% and 63% difference in the number of model parameters, and a decrease in inference time and floating point operations respectively. The experiments indicate that our improved method not only enhances the accuracy of YOLOv5 in detecting wood defects, but also enables a reduction in the volume and computational cost of the model parameters.
The article presents a complete approach for the wood industry for assessing the state of circular economy adoption by companies. A methodology for achieving this purpose is proposed and then ...implemented with the help of a specific questionnaire. The study is based on a literature survey with two components, one relating to reports on the concept of circularity and one relating to the methodological aspects of determining and measuring the progress of companies. Starting from these aspects and factoring in the sectoral evolution in Romania, the assessment directions and detailed questions for each are established essentially through a mind-mapping process. For validation, the questionnaire with seven evaluation viewpoints covered in 28 items is applied within the Romanian wood industry to 60 companies. The analysis of results is carried out using descriptive and inferential statical methods, such as ANOVA, showing good progress of the industry at company level, through individual efforts as well as the need to continue the transformation of the sector from the point of view of regulatory oversight and market acceptance. A set of recommendations for companies to advance their situation is proposed to help the maturation of the current circular approaches.
In several processes of the forest products industry, an in-depth knowledge of log and board internal features is required and their determination needs fast scanning systems. One of the possible ...technologies is X-ray computed tomography (CT) technology. Our paper reviews applications of this technology in wood density measurements, in wood moisture content monitoring, and in locating internal log features that include pith, sapwood, heartwood, knots, and other defects. Annual growth ring measurements are more problematic to be detected on CT images because of the low spatial resolution of the images used. For log feature identification, our review shows that the feed-forward back-propagation artificial neural network is the most efficient CT image processing method. There are also some studies attempting to reconstruct three-dimensional log or board images from two-dimensional CT images. Several industrial prototypes have been developed because medical CT scanners were shown to be inappropriate for the wood industry. Because of the high cost of X-ray CT scanner equipment, other types of inexpensive sensors should also be investigated, such as electric resistivity tomography and microwaves. It also appears that the best approach uses various different sensors, each of them having its own strengths and weaknesses.
The motivations for the National Research Project on the Short Wood Supply Chain stem from the recognition of the great importance of the wood-based bio-economy for the future carbon-free society. In ...addition to the essential ecological benefits provided by forests, natural wood resources are expected to play a significant role due to the increasing wood demand for structural and non-structural uses. However, in Italy most industrial wood products are made from imported timber, which results in poor attention to local forestry, loss of traditional silvicultural know-how and reduced forest employment in most mountain areas. The project specifically aims: (i) to assess the feasability and sustainability of wood short supply chains; (ii) to promote new models of environmental certification and energy efficiency analysis; (iii) to create innovative products for bio-building (CrossLam, laminated timber, wood panels) using wood assortments from sustainable forest management in Italy; (iv) to characterise the functionality of wood products (with attention paid to architectural issues), predict wood degradation rate and assess conservation methods. Attention is specifically devoted to most common forest species in Italy, such as beech, pines, chestnut, deciduous oaks and poplar and to test thermal and surface treatments with natural substances and nano-materials.
This paper presents a literature review of recent research on introducing the Industry 4.0 approach to improving energy efficiency, especially in the wood industry. While researchers focus on ...processes, service, and customer concepts, the effect on energy consumption is less addressed in these studies and applications. This paper focuses on previous works that discuss how to apply Industry 4.0 concepts to energy issues, such as to achieve better efficiency and performance for the industry in general and the wood industry in particular. The complexity of the study requires a multistep development. First, we define each concept separately and the relationships between them. Second, we apply a search algorithm to find related articles with specific terms, and then use the PRISMA method to select the most important ones, eliminating duplicates and excluding articles that do not mention energy efficiency and Industry 4.0 in the manufacturing or wood industry. Third, we explain and categorize the results and consolidate the study with brief examples from other industries. Finally, we conclude the study by mentioning the limitations and perspectives.
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