Paper Recycling Process Research Articles

Prediction of Flotation Deinking Performance: A Comparative Analysis of Machine Learning Techniques

Flotation deinking is one of the most widely used techniques for the separation of ink particles from cellulose fibers during the process of paper recycling. It is a complex process influenced by a variety of factors, and is difficult to represent and usually results in models that are inconvenient to implement and/or interpret. In this paper, a comprehensive study of several machine learning methods for the prediction of flotation deinking performance is carried out, including support vector regression, regression tree ensembles (random forests and boosting) and Gaussian process regression. The prediction relies on the development of a limited dataset that assumes representative data samples obtained under a variety of laboratory conditions, including different reagents, pH values and flotation residence times. The results obtained in this paper confirm that the machine learning methods enable the accurate prediction of flotation deinking performance even when the dataset used for training the model is limited, thus enabling the determination of optimal conditions for the paper recycling process, with only minimal costs and effort. Considering the low complexity of the Gaussian process regression compared to the aforementioned ensemble models, it should be emphasized that the Gaussian process regression gave the best performance in estimating fiber recovery (R2 = 97.77%) and a reasonable performance in estimating the toner recovery (R2 = 86.31%).

Recyclability of wastepaper containing cellulose nanofibers

Cellulosic/lignocellulosic nanofibers (CNF/LCNF) are value-added products which recently have been considered widely. This study focused on valorization of waste by making CNF from white cutting wastepaper (WCW), which was confirmed by the transmission electron microscope images. The CNF present in the paper recycling process showed significant effects on the final product and process aspects. Addition of 5% CNF (based on dry weight of pulp) to the recycled fibers improved the strength properties as well as the fines retention. But in contrast, the drainage decreased from 303 to 188 mL CSF. Finally, considering the importance of wastepaper history on the quality of recycling process and final products, as a new vision, this study focused on recyclability of wastepaper which has experienced CNF as an additive in their history of papermaking. In this respect, the papers reinforced with nanofibers in their history, after several recycling, experienced less reduction in the tensile and tear indices and fines retention. In summary, it seems that the presence of CNF in the wastepaper can slow down the reduction of product density and process properties during several recycling cycles and so restore their potential for subsequent papermaking cycles.

Investigating the effects of boron compounds on the cellulose fiber performance in paper recycling process

Investigating the effects of boron compounds on the cellulose fiber performance in paper recycling process

Pemanfaatan Daur Ulang Kertas Bekas Pada PT. Transportasi Jakarta Menjadi Nilai Tambah Bagi Kesejahteraan Masyarakat Binaan Bank Sampah Kumala

This Community Empowerment Program aims to enhance the well-being of the community around PT. Transportation Jakarta through the utilization of recycled paper. The initiative focuses on collaboration with Bank Sampah Kumala to create added value from the paper recycling process. Firstly, education is provided to the community and employees of PT. Transportation Jakarta about the importance of paper recycling and its positive environmental impact. Subsequently, a partnership is established with Bank Sampah Kumala to collect used paper from PT. Transportation Jakarta. The used paper is then processed through an environmentally friendly recycling process. This community service provides dual benefits. First, it reduces the amount of paper waste entering landfills, potentially mitigating negative environmental impacts. Second, the recycled paper products are sold, providing additional income to the community under the care of Bank Sampah Kumala. The increased income is expected to contribute positively to the well-being of the surrounding community. By involving PT. Transportation Jakarta and Bank Sampah Kumala, this community service creates synergy between the company, the community, and waste management institutions. Thus, the project not only generates a positive impact on paper waste management but also enhances community well-being through additional income

Environmental sustainability assessment of different end-of-life scenarios for the pulper rejects produced in the paper recycling process

Resource recovery from wastes through recycling processes promotes near-zero-waste residue business models and supports the circular economy's goals by facilitating the closure of loops in industrial systems and reducing energy and resource consumption as well as pollutant emissions. However, the approach is sustainable only when the waste can be valorized, and the environmental impact of the recycling is lower with respect to other end-of-life (EOL) scenarios. Due to the diversity and complexity of wastes streams, these aspects need to be evaluated on a case-by-case basis.This study focuses on a mechanical recycling process for pulper rejects, a mixed waste stream generated during recycled paper production, with two aims: (1) to define a feasible mechanical recycling process and (2) to evaluate its environmental performance through life cycle assessment (LCA) compared to the most common EOL treatments, such as incineration with energy recovery and landfilling. ReCiPe 2016 H method was used to estimate the environmental impacts of all scenarios, adopting both midpoint and endpoint approaches, on a functional unit (FU) defined as 1000 kg of pulper rejects. The LCA results indicate that the pulper rejects recycling is always preferable to landfilling across all impact categories considered. On the contrary, in comparison to incineration, the best environmental option depends on the specific impact category considered. In particular, recycling is the best EOL alternative in terms of impacts on global warming, with an impact 33 % lower, but it is not the most sustainable one in terms of fossil resource consumption, mainly due to the amount of energy required during all steps of the recycling process, while allowing the recovery of materials that would otherwise be lost. Currently, it is not possible to identify an overall ‘winner’ between incineration with energy recovery and recycling for the pulper rejects because the most environmentally sound alternative varies depending on the priority given to different environmental issues. Therefore, further improvements of the pulper rejects recycling pathway performances are required to make the process even more efficient and competitive.

Utilizing rejected contaminants from the paper recycling process in fired clay brick production

Building materials drive the global economy, yet face severe environmental hurdles: resource depletion, greenhouse gas emissions, and waste generation. In order to mitigate the impact from these challenges, authorities seek sustainable and eco-friendly alternatives as an urgent need. This study focuses on the utilization of as-received rejected contaminated fines (RCF) obtained from the yellow bins' waste (paper) recycling process, in brick production. Diverse tests assessed the brick performance, including compressive strength, absorption rate, thermal conductivity, 3D CT scanning for morphological analysis, and durability analysis. Additionally, a leachate analysis was performed to evaluate the environmental implications. Economic benefits, particularly the reduction of CO2 emissions, were also evaluated. The findings confirmed that as-received waste can be utilized for fired clay brick production without the need for pulverization. The novel brick product made with as-received RCF waste exhibited superior thermal characteristics (up to a 31.25 % reduction compared to control bricks) while meeting the essential compliance requirements outlined by national standards. Moreover, each firing cycle led to a potential value of up to USD 158,460 through a reduction of 417 tonnes of CO2, resulting from a 9.5 % reduction in firing temperature (1000 °C). The results from this study offer valuable insights into the potential of using RCF waste as a sustainable alternative in the brick manufacturing industry. This alternative could address the soaring demand in the current market, resolve the escalating solid waste crisis, and mitigate clay shortages, while providing a sustainable solution for the brick industry.

Bisphenol A in German watersheds: Part II. FlowEQ model-based characterization of sources and current and future conditions.

Increasing scientific and regulatory concern regarding environmental concentrations of bisphenol A (BPA) increases the need to understand the sources and sinks of this chemical. We developed a coupled flow network/fugacity-based fate and transport model to assess the contribution of different emissions sources to the concentration of BPA in surface water in Germany. The model utilizes BPA loadings and sinks, BPA physicochemical properties, a water flow network, environmental characteristics, and fugacity equations. The model considers industrial emissions, leaching from BPA-containing articles, wastewater treatment and bypass events, and emissions from landfills. The model also considers different scenarios that account for changes in the usage profile of BPA. Model predictions compare favorably to measured surface water concentrations, with the modeled concentrations generally falling within the range of measured values. Model scenarios that consider reductions in BPA usage due to government-mandated restrictions and voluntary reductions in usage predict falling BPA concentrations that are consistent with the most recent monitoring data. Model predictions of the contributions from different usage scenarios and wastewater treatment methods can be used to assess the efficacy of different restrictions and waste handling strategies to support efforts to evaluate the costs and benefits associated with actions aimed at reducing BPA levels in the environment. This feature of the model is of particular importance, given current efforts to update the regulations regarding BPA usage in the EU. The model indicates that as the current restriction on BPA in thermal paper works through the paper recycling process, BPA concentrations will continue to decrease. Other actions, such as upgrades to the stormwater and wastewater infrastructure to minimize the frequency of storm-related bypasses, are predicted to provide more meaningful reductions than additional restrictions on usage. Integr Environ Assess Manag 2024;20:226-238. © 2023 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Assessment of Melt Compounding with Zeolites as an Effective Deodorization Strategy for Mixed Plastic Wastes and Comparison with Degassing.

The emission of off-odors from mechanically recycled plastics severely limits their re-introduction into the market for the production of new objects, for the same use or even for less demanding applications, thus hindering the implementation of an effective circular economy for plastics. The addition of adsorbing agents during the extrusion of polymers represents one of the most promising strategy to reduce the odorous emissions of plastics, due to its characteristics of cost-effectiveness, flexibility and low energy consumption. The novelty of this work lies in the assessment of zeolites as VOC adsorbents during the extrusion of recycled plastics. They appear more suitable than other types of adsorbents, due to their ability to capture and "hold" the adsorbed substances at the high temperatures of the extrusion process. Moreover, the effectiveness of this deodorization strategy was compared with the traditional degassing technique. Two types of mixed polyolefin wastes, coming from completely different collection and recycling processes, were tested: Fil-S (Film-Small), deriving from post-consumer flexible films of small size, and PW (pulper waste), which is the residual plastic waste obtained from the paper recycling process. The melt compounding of the recycled materials with two micrometric zeolites (zeolite 13X and Z310) resulted as more effective in the off-odors removal with respect to degassing. In particular, the highest reduction (-45%) of the Average Odor Intensity (AOI) was measured for both PW/Z310 and Fil-S/13X systems at 4 wt% of the zeolites' amount, compared with the corresponding untreated recyclates. Finally, by combining degassing and melt compounding with zeolites, the best result was obtained for the composite Fil-S/13X, whose Average Odor Intensity resulted as quite close (+22%) to the one of the virgin LDPE.

Identification and characterization of sticky contaminants in multiple recycled paper grades

Organic sticky contaminants represent one of the biggest technical challenges in the paper recycling process. These contaminants reduce paper strength, cause plugging of wires and felts, and stick to or deposit on machine parts affecting the runnability of the paper machine. The removal of these sticky contaminants is difficult to achieve along the process due to the heterogeneous nature of these organic contaminants. In this study, the nature of sticky contaminants in multiple wastepaper grades was analyzed and characterized using screening, solvent extraction with subsequent analysis such as FT-IR, GC-MS, and SEM. The content of stickies in wastepaper varies among different paper grades and their recovery methods. The wastepaper from curb side collection contains nearly 4 times the amount of stickies than most of the wastepaper grades collected from a local paper recycling mill. Polyvinyl acetate polymers, styrene butadiene rubber (SBR), paraffin waxes and polyamines are the major components in the extracted sticky contaminants. In addition, these stickies deposit heavily on fibers surface leading to high negative charge in fibers suspension ranging between 2 and 4.5 µeq/L. It is expected that these findings will assist addressing the knowledge gaps in understanding the nature of stickies and their behaviors, and to eventually develop highly efficient technologies for contamination removal in the paper recycling process.

The role of public sector policy in sustainable energy efficiency: an application of dynamic modelling

ABSTRACT Environmental protection and sustainability are long-standing issues in European Union policies. In this study, we focused on public policy related to waste management. Information on waste disposal guidelines is communicated to public authorities and citizens through public policy. The crucial question is whether the implementation of this policy achieves the objectives. The present analysis was based on a dynamic model of the repeated recycling and energy utilization process of sorted paper using a coloured Petri net. This model allowed for the isolation and monitoring of energy use in relation to the input amount, enabling the investigation of the potential energy efficiency of the paper recycling process. The breakpoint was calculated in terms of energy efficiency, gradual recycling and subsequent energy use. The calculation proved that, until this breakpoint is reached, recycling does not result in greater energy savings than the direct use of sorted paper for energy production. These findings have significant implications for the design and formulation of public policy for both the European Union and national governments.

Improving the properties of mortars by using recycled paper ash flakes

Abstract This study addresses the need to improve life on earth by finding a way to reintroduce ubiquitous waste back into the system. On a hand, there is the amount of cellulosic waste that can no longer be reintroduced into the paper recycling process. On the other hand, the amount of cement used globally, is growing alarmingly. My study seeks the balance of a mix of these two materials, which would generate desirable effects both from an engineering and ecological point of view. Paper ash, is a material made of particles of various sizes and can play various roles in the composition of mortars. The efficacy of particles up to 0.025 mm in size (powder ash) as a cement substitute and the efficiency of particles in size between 0.025 and 8 mm (flakes) as a pozzolanic additive are demonstrated. The results of the mechanical tests to which the samples were subjected show the possibility of reducing the amount of cement used in standard recipes by adding ash from recycled paper, without compromising the physical and mechanical properties of the mortars. The cement economy can rise up to 20 percent while the mechanical strength increases by 5-10 percent compared to the basic recipe.

“Caracterización y Reducción de la materia disuelta y coloidal en la fabricación de papel y cartón reciclado en la empresa Inpetfa sac.”

La utilización de papel y cartón de recuperación como materia prima para la fabricación de papel y cartón reciclado, presenta numerosas ventajas al medio ambiental y económico. Sin embargo, también tiene graves inconvenientes debido a la cantidad de contaminantes que se introducen en el sistema. Los contaminantes que se encuentran en forma de materia disuelta y coloidal no pueden ser eliminados por los procesos mecánicos convencionales y cuando se desestabilizan, por un cambio brusco de las condiciones del sistema, son responsables directos de la formación de manchas y agujeros en el producto final. El objetivo del presente trabajo es desarrollar un procedimiento para determinar la presencia de materia disuelta y coloidal en el agua del proceso papelero, de manera práctica y precisa. Las aguas caracterizadas, se desestabilizan con un polímero catiónico, favoreciendo la formación de depósito diseñado para tal fin, que permite llevar a cabo la determinación cuantitativa mediante un sistema de análisis Físico Quimico. Con el método desarrollado, una vez validado y determinada su reproductividad, se lleva a cabo un estudio con aguas reciclada obtenida a partir de las suspensiones de pasta que contienen los contaminantes propios del proceso del reciclado de papel, tales como: adhesivos, ceras, jabones de destintado, etc. Se estudia el efecto que ejercen distintas variables, como la naturaleza del contaminante, la presencia de aditivos de destintado, la naturaleza de los agente de desestabilización y las características del medio (Ph, Temperatura, Solidos Totales, DQO, DBO5, Aceites y Grasas etc.); así mismo, se lleva a cabo un estudio de las aguas del proceso, con materia disuelta y coloidal contenida en muestras de diferentes tipos de materia primas: papel mixto, periódico y cartón reciclado, obteniendo los resultados después del tratamiento Físico Quimico en promedio. (Ph = 8.4; Temperatura = 26.5°C; Solidos Totales = 150.26 mg/L; DQO = 750.82 mg/L; DBO5 = 300.24 mg/L; Aceites y Grasas = 48.56 mg/L etc.); en la fabricación de planchas de Fibras aglomeradas en la empresa Inpetfa sac.

Alite and Belite obtained from the sludge of a paper recycling process

In this work, the feasibility of obtaining Alite and Belite with possible applications in the cement industry from the primary sludge generated by a paper recycling industry in the State of Santa Catarina, Brazil was studied. The effect of the heat treatment on the physical and chemical properties of the primary sludge was studied, when treated at 800 °C, 875 °C and 950 °C, and defined by studies using the dilatometry technique. The treated sludge at these temperatures was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), thermal dilatometry (TD), X-ray fluorescence spectroscopy (XRF), surface analysis by the method of Brunauer, Emmett, Teller (BET), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The results showed the appearance of the Alite and Belite phases with different proportions, depending on the temperatures used during the heat treatment processes and with sufficient quality for application in the cement industry, since the optimal condition to obtain Alite is the heat treatment at 950 °C. In addition, the temperatures used were lower than those used in the conventional processes of Alite and Belite.

The Effect of Phase on Paper Thickness Optimization in the Paper Recycling Process Using Recycling Machine

AbstractEfforts to manage the recycling of paper waste into new paper have been carried out in recent times. It takes a tool or machine that is able to effectively and efficiently recycle used paper into new paper. There are several factors that affect the effectiveness of paper recycling machines, one of which is the paper thickness. One method that can be used to analyze the factors that influence paper thickness in the paper production process using a paper recycling machine is regression analysis. Regression analysis is data analysis techniques in statistics that is used to examine the relationship between several independent variables and dependent variable. However, if we want to examine the relationship or effect of two or more independent variables on a dependent variable, the regression model used is a multiple linear regression model. This study purposes are to analyze the factors that influence paper thickness using a paper recycling machine using multiple linear regression and to inform the modeling about that. The results showed that the factors that affect the paper thickness optimization are destruction and press phase. AbstractUpaya pengelolaan daur ulang sampah kertas menjadi kertas baru telah banyak dilakukan pada jaman sekarang. Dibutuhkan suatu alat atau mesin yang mampu secara efektif dan efisien dalam mendaur ulang kertas bekas menjadi kertas baru. Terdapat beberapa faktor yang mempengaruhi tingkat efektifitas mesin daur ulang kertas diantaranya adalah ketebalan kertas. Salah satu metode yang dapat digunakan untuk menganalisis faktor-faktor yang mempengaruhi ketebalan kertas pada proses produksi kertas menggunakan mesin daur ulang kertas adalah analisis regresi. Analisis regresi merupakan teknik analisis data dalam statistika yang digunakan untuk mengkaji hubungan antara beberapa variabel bebas dengan variabel tidak bebas. Namun, jika ingin mengkaji hubungan atau pengaruh dua atau lebih variabel bebas terhadap satu variabel tidak bebas, maka model regresi yang digunakan adalah model regresi linier berganda. Tujuan dalam penelitian ini yaitu menganalisis faktor-faktor yang mempengaruhi ketebalan kertas menggunakan mesin daur ulang kertas menggunakan regresi linier berganda serta memberikan informasi pemodelan mengenai hal tersebut. Hasil penelitian menunjukkan bahwa faktor yang mempengaruhi keoptimalan ketebalan kertas adalah fase penghancuran dan pemadatan kertas

Contactless Resonant Cavity Dielectric Spectroscopic Studies of Recycled Office Papers

Current product composition and quality test methods for the paper and pulp industries are rooted in wet-bench chemistry techniques which cannot be used to distinguish between virgin and secondary fibers. We have recently demonstrated the application of an in situ and nondestructive assessment method based on dielectric spectroscopy (DS), which can address this deficiency in the testing of paper. The DS technique, which employs a resonant microwave cavity, could be applicable to quality assurance techniques such as gauge capability studies and real-time statistical process control (SPC), and may have inherent forensic capabilities. In this paper, we show how this DS technique can be used to distinguish between office copier paper products which may contain recycled fibers. We show a reasonable correlation between the dielectric characteristics (e.g., dielectric loss) and the atomistic level chemical changes that result from the paper recycling process.

Deinking of Black Toner Ink from Laser Printed Paper by Using Anionic Surfactant

The objective of this research was to synthesize natural anionic surfactant from renewable material and use of this surfactant for ink removal from printed paper via flotation deinking in paper recycling process. The work included the preparation of the castor seed raw material, extraction of castor oil, preparation of anionic surfactant and deinking flotation of waste printed paper. Foamability and foam stability, critical micelle concentration and hydrophilic lipophilic balance of the surfactant was characterized and used to evaluate its fundamental deinking ability properties for the purpose of deinking flotation. The hydrophilic-lipophilic balance (HLB) of the fatty acid soap of 19.48, average Foamability height of 49cm and critical micelle concentration (CMC) of 0.0065M was obtained. Lab scale flotation deinking process was done and the basic flotation parameters like flotation time, fatty acid soap dosage and pH were optimized for evaluating deinking efficiency. The flotation deinking efficiency was probed by measuring the residual ink concentration of the hand sheet via Perkin Elmer spectroscopy before and after deinking flotation. The individual and interaction effects between the basic parameters were studied by using design Expert Software 6.0.8. For the deinking flotation, the maximum ink removal efficiency was determined to be 78.02% at the flotation time of 90min, fatty acid soap dosage of 1.5% and pH of 9. Increasing flotation time from 30min up to 90 min and decreasing fatty acid dosage from 3% to 1.5% and increasing of pH from 3 up to 9 were found to have increased the ink removal efficiency.

Stepwise pyrolysis of mixed plastics and paper for separation of oxygenated and hydrocarbon condensates

Mixed plastics and papers are two of the main fractions in municipal solid waste which is a critical environmental issue today. Recovering energy and chemicals from this waste stream by pyrolysis is one of the favorable options to achieve a circular economy. While pyrolysis products from plastics are mainly hydrocarbons, pyrolysis products from paper/biomass are highly oxygenated. The different nature of the two pyrolysis products results in different treatments and applications as well as economic values. Therefore, separation of these two products by multi-step pyrolysis based on their different decomposition temperatures could be beneficial for downstream processes to recover materials, chemicals and/or energy. In this work, stepwise pyrolysis of mixed plastics and paper waste was performed in a batch type fixed bed reactor using two different pyrolysis temperatures. Neat plastic materials (polystyrene, polyethylene) and cellulose mixtures were used as starting materials. Then, the same conditions were applied to a mixed plastics and paper residue stream derived from paper recycling process. The condensable products were analyzed by GC/MS. It was found that pyrolysis temperatures during the first and second step of 350 and 500 °C resulted in a better separation of the oxygenated and hydrocarbon condensates than when a lower pyrolysis temperature (300 °C) was used in the first step. The products from the first step were derived from cellulose with some heavy fraction of styrene oligomers, while the products from the second step were mainly hydrocarbons derived from polystyrene and polyethylene. This thus shows that stepwise pyrolysis can separate the products from these materials, although with some degree of overlapping products. Indications of interaction between PS and cellulose during stepwise pyrolysis were observed including an increase in char yield, a decrease in liquid yield from the first temperature step and changes in liquid composition, compared to stepwise pyrolysis of the two materials separately. A longer vapor residence time in the second step was found to help reducing the amount of wax derived from polyethylene. Results from stepwise pyrolysis of a real waste showed that oxygenated and acidic products were concentrated in the liquid from the first step, while the product from the second step contained a high portion of hydrocarbons and had a low acid number.

The effect of papermaking sludge as an additive to biomass pellets on the final quality of the fuel

The ever increasing demand on top quality solid biofuel in form of biopellets is limited by the sources and properties of raw materials. The best quality biopellets are suitable for burning in small scale boilers up to 100 kWt. The most limiting factor of this fuel is the ash melting temperature. Therefore the use of cheaper and readily available phytomass as a raw material is considerably restrictive. The research in this paper is based on the theory of the chemical process of ash creation and on the effect of additives on this process. The objective of the study is to find and apply an effective and available additive to produce the best quality phytomass-based fuel pellets, suitable for small scale boilers. A by-product of the paper recycling process, papermaking sludge was used as the most effective additive to wheat straw. This is due to the high content of calcite and kaolin in the sludge. It was also confirmed by experiments that the composition of sludge including cellulose fibres very positively affects the physical and mechanical properties of the composite pellets. Our research deals with an experiment concerning an appropriate production process of composite fuel based on wheat straw. Different weight proportions of papermaking sludge were added and the effect of the sludge on the fuel parameters, especially on the ash melting behaviour, was observed. The final quality of the composite fuel was thoroughly tested by physical, mechanical and thermal methods, and its properties were compared to European and International Standards for Biofuels. The results of the experiments demonstrate that the composite pellets produced by the above-mentioned process have a high level of fuel quality and, due to high ash melting temperature, they are suitable for small scale boilers. The results have shown that the appropriate range of papermaking sludge content for producing high quality wheat straw composite pellets ranges from 10% to 20%.

The influence of material flow on ecological cost in the waste paper recycling and manufacturing process

The influence of material flow on ecological cost in the waste paper recycling and manufacturing process

Statistical experimental design of a novel deinking reactor based on centrifugal force under electric field concept

The aim of this research was to study a new invention concept of ink removal processes by a combined effect of centrifugal force and electrical force. After deinking treatment with different voltage conditions, the effective residual ink concentration (ERIC) index from the test samples were lower than the operation without voltage input, indicating the applied electric force promotes deinking. With a certain operating time and ink coverage, the percentage weight loss of the pulp yield after deinking treatment has been lower by applying electrostatic force. From an analysis of variance (ANOVA), the optimum point of the process was obtained with low ink coverage of used paper, medium operating time and high voltage supply. This novel electrostatic separation is proved to be an effective method for paper recycling process since it has no chemical usage; thus, no requirement for further chemical separation.