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The supply-chain water footprint of paper
Published in Arjen Y. Hoekstra, The Water Footprint of Modern Consumer Society, 2019
The final factor to be taken into account is the fraction of pulp used in paper production that is derived from wood and not from recycled paper. Paper recycling is an important factor for the water footprint, because fully recycled paper avoids the use of fresh wood and thus nullifies the water footprint in the forestry stage. When more recovered paper is used, the overall water footprint will decrease. On average, an estimated 41 per cent of all produced pulp is obtained from recycled paper (FAO and CEPI, 2007; UNECE, FAO, 2010), with large differences between producers using no recycled paper at all to producers that achieve relatively high percentages. The ‘recovered paper utilization rates’ for the main pulp-producing countries are shown in Table 10.2. This rate is defined as the amount of recovered paper used for paper and paperboard as a percentage of paper and paperboard production. Losses in repulping of recovered paper are estimated to be between 10 and 20 per cent (FAO and CEPI, 2007). For the water footprint estimates that will be shown later on in this chapter we assumed a loss of 15 per cent for all countries.
Ill Recycling of Paper
Published in Susan E. M. Selke, Packaging and the Environment, 1994
Paper recycling starts with the resuspension of paper fibers into a pulp slurry. This is generally performed in either a beater or a hydropulper, where mechanical action resembling that in a kitchen blender separates the fibers. In addition to a pulper, all secondary fiber pulping systems include a device to remove heavy “junk” from the stream, a device to remove rags, strings, and metallic wires, a screening system to remove oversize particles, and centrifugal separation for further cleaning (Carr, 1991; Felton, 1980). In some cases de-inking is required, and then chemicals will be used to disperse and wash away the ink. Ink typically amounts to 0.5-2.0 percent of the paper by weight, but total stock loss when de-inking is required usually ranges from 15-40 percent (Felton, 1980). The de-inking process most commonly used in the United States was washing, while flotation was preferred in Europe and Japan. Most mills now being built in the United States and Canada use flotation, either alone or along with a washing system. Flotation is recognized as the preferred process because it causes less fiber loss, and uses less energy and less water than washing. It can also remove heat-set inks, plastics, and other non-water soluble contaminants, which washing cannot. However, it is not as effective at removing clay and fines. An interesting side effect of this change in technology is a demand for old magazines, ideally in a 30:70 ratio with old newsprint. The magazines supply clay which stabilizes the air bubbles used to float off the ink particles from the pulp (Carr, 1991; Glenn, 1992).
Microbial Enzymes for Eco-friendly Recycling of Waste Paper by Deinking
Published in Ram Chandra, R.C. Sobti, Microbes for Sustainable Development and Bioremediation, 2019
Sanjeev Balda, Aarjoo Sharma, Neena Capalash, Prince Sharma
Paper recycling is gaining more importance due to increasing environmental and economic concerns. Paper recovery rates are increasing continuously in the United States and European countries. Due to rapid developments and increasing efficiency of technology, the quality of the recycled paper is approaching that of virgin paper. However, there are environmental and ecological concerns related to paper recycling. The biggest problem is the solid waste rejects and sludge recovered from paper processing mills which are in the range between 5% and 40%, depending on different paper grades.
Application of response surface methodology (RSM) for optimizing coagulation process of paper recycling wastewater using Ocimum basilicum
Published in Environmental Technology, 2020
Mohammad Reza Mosaddeghi, Farshid Pajoum Shariati, Seyed Ali Vaziri Yazdi, Gholamreza Nabi Bidhendi
Nowadays, the growth of human population has led to the development of different industries in fulfil the human needs. This phenomenon, eventually, has caused the excessive use of resources of the earth, such as soil, air, water, etc. One of the most polluting industries is the pulp and paper industry, which in terms of water consumption has the third place after chemical industries [1]. This industry generates 30 to 180 m3 of wastewater per every ton of pulp production and 20 to 70 m3 of wastewater per every ton of paper production [2]. Wastewater is the effluent of the various stages of pulp and paper production, such as chips, pulping, bleaching, paper-making, and paper recycling [3]. Furthermore, the wastewater contains toxic agents, including metals, sterols, suspended solids, fatty acids, tannins, lignin and its derivatives, and high levels of some parameters such as colour, turbidity, TSS (total suspended solids), and COD (chemical oxygen demand). Thus, the treatment process seems to be either costly or difficult [4]. The physicochemical and biological methods are regularly used to treat the pulp and paper wastewater. The biological processes are divided into aerobic and anaerobic processes to eliminate organic agents [5]. Physicochemical processes include sedimentation, filtration, flotation, coagulation, flocculation, ozonation, and adsorption [6]. One of the mentioned processes which is inexpensive and simple to use is the coagulation and flocculation, which is extensively used in the primary treatment of pulp and paper wastewater [7]. This process is based on the use of metal salts to form flocs and neutralize the surface charge of small particles in wastewater [8]. The process makes the wastewater easily filterable [9]. Among the effective factors in this process are pH [10,11], the concentration of coagulant and flocculant [10,12], and mixing time [13,14].
Evaluation of life cycle assessment in a paper manufacture by analytical hierarchy process
Published in International Journal of Sustainable Engineering, 2021
Mohammad Moosavi, Payam Ghorbannezhad, Majid Azizi, Hamid Zarea Hosseinabadi
The decision-making process is a two-step comparison, which is the most important step in several metrics that use qualitative data. the pairwise comparisons are determined using a scale. this scale is a mapping between a set of discrete linguistic choices available to the decision-maker and a discrete set of numbers representing the importance or weight. to compare the environmental impact of different waste management scenarios, a combination of LCA and the method is used. in the first step, LCA is used to evaluate the environmental impacts of developed scenarios and calculate the quantities of impact categories (indices), global warming (matter), global acidification, toxicity for humans, and eutrophication. in the next stage, the method is used to rank the developed scenarios according to the target. The life cycle assessment boundary from the paper mill as shown in Figure 3, includes six steps: waste paper collection, pulp production, virgin pulp production, transport and stock consumption, paper recycling, and non-recyclable matter (Liu et al. 2020; Nie et al. 2018). It is anticipated that the thermomechanical pulp (TMP) process is a significant energy consumer as an alternative raw material provider in a recycled paper mill. Utilisation of de-inking pulp (DIP) from 15% to 85% can be shutting down the TMP process and reduce the external energy resources. Therefore, retrofitting the existing process with the DIP machinery system inaugurates the high yield product and generates less sludge. Life cycle assessment (LCA) is used as an environmental management tool with a cradle to grave approach to evaluate various systems and can assess the environmental impacts throughout the life cycle of a process. This method is very different from other evaluation tools due to its ability to evaluate the entire life cycle of a process, however, it is possible to use the information collected by other techniques. The use of life cycle assessment (LCA) as an environmental management tool in different methods and titles has been started since 1960. In fact, in this method, by carefully reviewing and auditing, all resources used to produce the product and all materials released to the environment are evaluated and focuses on the least environmental consequences in product or process selection. In recent years, two approaches to life cycle assessment (LCA) have emerged:
Cleaner production solution selection for paper making – a case study of Latif paper products Co. Iran
Published in International Journal of Sustainable Engineering, 2018
Majid Azizi, Yaghoob Asadizadeh, Charles Ray, Yahya Hamzeh
The research was conducted in two stages. In the first stage, five major groups of cleaner production in Latif recycle paper mill (process change, product modification, renewal, preventive maintenance and man power) were identified. Weighting values of the factors and their sub-criteria were derived by applying the Analytic Hierarchy Process (AHP) using Expert Choice software. In the second stage, the weighted values of the solutions of cleaner production in the factory (reduction of environmental pollution, reduction of water consumption, reduction of raw material consumption, reduction of fuel consumption, reduction of electricity consumption, reduction of additives materials and reduction of solid wastes) were synthesised using the same technique. Our conclusion is that the factors process change and product modification were the most important criteria for significant process improvement. The study also indicated that existence of industrial automation and technology level was the most dominant sub-criterion priority for CP implementation in the Latif recycle paper mill. In addition, some higher priority sub-criteria such as: use of higher quality inclusion, and implementation of calibration system are related to process change. Therefore, to achieve cleaner production goals and implementation of its strategic objectives it is necessary to pay more attention to this criterion. Alternatives such as reduction of environmental pollution and water consumption are most important solutions to attain environmental process and energy improvement in the recycle paper mill. Using 100% deinked pulp, reducing the use of chemical materials, reducing the dependence and need on original paper, recycling of waste materials and exhaust gases, reduction of fossil fuel consumption lead to reduction of environmental pollution. On the other hand, closed systems without any wastewater, the use of modern refinement system, continuous availability of repairmen for leakages in pipes, as well as cylinder dryers and recycling of output water can cause reduction of water consumption. Results of sensitivity analysis reveal that if weight associated with product modification of the main criterion examined can justifiably be decreased, or if weights associated with process change, preventive maintenance and renewal justifiably increased, Alternative W (reduction of water consumption) will become the preferred option. Manpower criterion is not very sensitive in this regard.