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• Pulp and paper mill sludge (PPMS) landfill sites have GHG assessment challenges. • GHG fluxes measured by chambers with (F +) and without (F-) a frame were compared. • Flux relationships up to 80 % were shown between F- and F + chambers (the standard) • Correction factors for F- chambers were built to estimate fluxes from F + chambers. • The approach can refine GHG inventories on PPMS landfill sites. Assessments of greenhouse gas (GHG) emissions in managed areas are facing various challenges. A non-flow-through, non-steady-state (NFT-NSS) chamber coupled to a frame permanently inserted into the landfilled substrates is a standard method for quantifying GHG emissions in managed areas, such as pulp and paper mill sludge (PPMS) landfill sites. Frequent measurements are needed to minimize uncertainties on GHG emission factors at the landfill site scale. However, maintaining a frame inserted into the substrates for a long time period is often impossible due to landfilling management operations. Therefore, GHG measurements using NFT-NSS chambers placed directly on substrates' surface could be an interesting option. Our objectives were to determine the relationships between CO 2 , CH 4 , and N 2 O fluxes measured with (F +) and without (F-) a frame inserted in the substrates' surface and to develop correction factors for fluxes measured without a frame. Measurements were made at different PPMS landfill sites in the province of Québec, Canada. Stronger GHG flux relationships were observed at the provincial (across sites) than the specific site scale: the variance in GHG fluxes from F- chambers explained up to 80 % of variance in fluxes from F + chambers. The measured CO 2 , CH 4 , and N 2 O fluxes in F- chambers were on average 53, 78, and 63 % lower, respectively, than those estimated by the models at provincial scale. The correction factors developed with this approach could greatly extend the number of sites where in situ GHG measurements can be done and would help refining GHG inventories at the provincial and national levels. [ABSTRACT FROM AUTHOR]

Tremendous attention has been paid to the water-associated side reactions and zinc (Zn) dendrite growth on the electrode-electrolyte interface. However, the Zn pulverization that can cause continuous depletion of active Zn metal and exacerbate hydrogen evolution is severely neglected. Here, we disclose that the excessive Zn feeding that causes incomplete crystallization is responsible for Zn pulverization formation through analyzing the thermodynamic and kinetics process of Zn deposition. On the basis, we introduce 1-ethyl-3-methylimidazolium cations (EMIm+) into the electrolyte to form a Galton-board-like three-dimensional inert-cation (3DIC) region. Modeling test shows that the 3DIC EMIm+ can induce the Zn2+ flux to follow in a Gauss distribution, thus acting as elastic sites to buffer the perpendicular diffusion of Zn2+ and direct the lateral diffusion, thus effectively avoiding the local Zn2+ accumulation and irreversible crystal formation. Consequently, anti-pulverized Zn metal deposition behavior is achieved with an average Coulombic efficiency of 99.6% at 5 mA cm-2 over 2,000 cycles and superb stability in symmetric cell over 1,200 h at -30 °C. Furthermore, the Zn||KVOH pouch cell can stably cycle over 1,200 cycles at 2 A g-1 and maintain a capacity of up to 12 mAh. [ABSTRACT FROM AUTHOR]

Torrefaction emerges as an industrial process that increases the energy content of conventional biomass. Primary and secondary sludge are the main solid residues generated in the Effluent Treatment Plants of bleached kraft pulp mills, and can be considered as biomass. Typically, these wastes are sent to industrial landfills. The present study aimed to evaluate the technical feasibility of transforming the primary sludge (PS), secondary sludge (SS) and mixed sludges (MIX) into torrefied biomass for energy generation. Three temperatures (260, 290 and 320 °C) and three residence times (20, 40 and 60′) were used in the sludge torrefaction process. Increasing the torrefaction temperature and residence time of the sludges produced several benefits on their physical and chemical properties. They promoted an increase in the heating value, due to the elimination of less energetic compounds and the concentration of the fixed carbon content; caused a reduction of moisture, with a consequent increase in the lower heating value of the sludges; and led to a high energy yield and an increased energy density, important parameters in sludges energy generation. The treatment at 320 °C for 60′ obtained increases of 76%, 27% and 41% over the reference, for PS, SS and MIX, respectively. [ABSTRACT FROM AUTHOR]

Routinely, the mills perform programmed maintenance shutdowns (PMS) that can affect the characteristics of the effluents and the performance of the effluent treatment plant (ETP). A careful planning of the PMS, along with the use of industrial process sectorial spill control and the use of the emergency spill lagoon have considerably minimized these effects. The Suzano pulp mill located in Aracruz (Brazil) has three production lines and carry out, on average, PMS of each production line separately, every 15 months of operation. The purpose of the study was to evaluate the effects of the PMS on the effluent characteristics and performance of the ETP compared to the periods of normal operation. The results showed that during the PMS, the physicochemical characteristics of the raw and treated effluents were like those found during normal operation. The lower organic loads found in the effluents during the PMS periods were associated with the decrease of the flow rates and the increase of the hydraulic retention time of the ETP, causing a better performance of COD, BOD, TSS and AOX removal. A proper planning of the PMS improved the performance of the ETP and the treated effluent quality remained similar to those during the normal operating period. [ABSTRACT FROM AUTHOR]

The suitability of industrial hemp (IH) as a source of fibres for European industrial-scale papermaking, including, in particular, European kraft pulp mills (EKMPs) (i.e., plants producing the predominant amount of virgin pulps in Europe), was discussed, considering the causal, cultivation, technological, and application aspects of this issue. The work showed that there are generally premises for using straw from nonwood crops in European papermaking. As for the IH, it was found that IH stalks are the best IH fibrous raw material for EKMPs. There are a few cultivation factors favouring the use of IH stalks in them and a few, though important (e.g., small cultivation areas), factors not conducive to this use. Most technological factors favour the use of IH stalks in EKPMs, apart from the large differences in the length of the IH bast and woody-core fibres. The analysis of application factors indicates lower usefulness of IH stalks than wheat, rye or triticale straws, stalks of Miscanthus × giganteus, Virginia mallow, and kenaf. This is due to the much greater availability of these cereal straws than IH and less variation in the fibre length of cereal straws, Miscanthus × giganteus, Virginia mallow, and kenaf than in IH stalks. The main conclusion from the conducted query is the statement that the presence of IH varieties with fibre lengths more similar to wood would reduce the number of technological and application factors unfavourable to their use in EKPMs and increase the competitiveness of hemp straw vs. wood as a raw material for European large-scale papermaking. [ABSTRACT FROM AUTHOR]

The pith is the internal part of the sugarcane plant with short and variable fiber length. The presence of pith creates process-related issues in papermaking, so it must be removed from the bagasse. Pith has low calorific value, and burning of pith in boilers also creates boiler operational issues as well as environmental pollution and health hazards. The imposition of stringent emission norms by the environmental regulatory bodies is compelling these industries to search for cleaner alternatives to fuels. Pith is generated in huge quantities so its disposal or management will become a major challenge if industries shift to cleaner fuel. Considering these pressing issues and some recent relevant research reported on pith valorization, this study was planned to explore the potential of pith valorization. Therefore, in the present review, research studies available on alternate routes for the valorization of pith into value-added products have been extensively covered. Since pith is also lignocellulosic biomass, therefore, its valorization after pretreatment and as such direct utilization (without pretreatment) has also been categorically discussed. Furthermore, the promising pathways and prospective research in pith valorization are discussed that will make the sugar and associated pulp and paper mill more economically and environmentally sustainable. [ABSTRACT FROM AUTHOR]

β-sitosterol (BS) is a phytosterol with wide potential in cosmeceutical, biomedical and food applications. In acid sulphite pulp cooking, BS and its derivatives are considered an underutilized natural source of bioactive compounds, which are adsorbed on the resulting pulp or dispersed in the spent liquor. In this work, a new method for the isolation of BS from alkaline extract (AE) of unbleached sulphite pulp purification stage is proposed. BS was recovered by two-step acidification of AE up to pH 3 under pre-selected conditions, followed by fractionation of the formed precipitate with water-miscible organic solvents, having obtained best results (>90% of BS purity; yield of 70-210 mg/dm3 of AE) with mefthanol fractionation followed by BS crystallization induced via addition of water (ca. 10% vol.). When ethanol was used instead, BS was detected in low amounts in the isolate, being fatty acid sterol esters and fatty acid glycerides the major components, as revealed from analyses by wet chemistry coupled with gas chromatography-mass spectrometry and thin layer chromatography (TLC). The method is adaptable for large-scale industrial production of BS and may represent an important source of sterol-based products. [ABSTRACT FROM AUTHOR]

A new method of recycling cooking with pulping wastewater was developed to save energy and reduce carbon dioxide emissions in a pulp mill, which used bio-fuel of eucalyptus instead of coal and oil, and reduced the steps of black liquor combustion and lime regeneration in the traditional pulp mill to reduce carbon dioxide emission. As results, the bio-fuel consumption and CO 2 emission are 2.04 × 104 MJ (1.2 tons of eucalyptus) and 2.2 tons for per ton of pulp. It reduces 28.23% of fuel energy consumption and 14.06% of CO 2 emission comparison with that by the traditional pulp mill. In addition, while using the generated lignin as part of bio-fuel, the product value-added is 765.88 RMB for per ton of pulp, being 23.72% lower than that of 1004.08 RMB by the traditional pulp mill. Therefore, this study demonstrates the advance and feasibility of using only bio-fuel for a new pulp mill with a new method of recycling cooking, and will promote the technological revolution of cleaner production in the pulp and paper industry. [ABSTRACT FROM AUTHOR]

Production planning and scheduling in the pulp and paper industry can be very challenging. In most cases, practitioners address the production planning process manually, which is time-consuming and sub-optimal. This study deals with production planning encountered in a pulp mill company involving different wood species, parallel heterogeneous lines, inventory limits, sequence-independent setup times and preventive maintenance. To tackle the problem, an efficient mixed-integer formulation is proposed that optimizes when, where and how much to produce of different wood species and schedules preventive maintenance to minimize the total setup times. Several computational experiments are conducted to solve a case study in a pulp mill company in Chile. The results show the capability of the model to support the decision-making process in the pulp and paper industry, providing an efficient tool for practitioners to solve the problem in a reasonable amount of time. [ABSTRACT FROM AUTHOR]

Pulp and paper mill sludge (PPMS) is currently disposed of into landfills which are reaching their maximum capacity. Valorisation of PPMS by enzymatic hydrolysis using cellulases is an alternative strategy. Existing commercial cellulases are expensive and contain low titres of β-glucosidases. In this study, β-glucosidase production was optimised by Aspergillus japonicus VIT-SB1 to obtain higher β-glucosidase titres using the One Variable at a Time (OVAT), Plackett Burman (PBD), and Box Behnken design (BBD)of experiments and the efficiency of the optimised cellulase cocktail to hydrolyse cellulose was tested. β-Glucosidase production was enhanced from 0.4 to 10.13 U/mL, representing a 25.3-fold increase in production levels after optimisation. The optimal BBD production conditions were 6 days of fermentation at 20 °C, 125 rpm, 1.75% soy peptone, and 1.25% wheat bran in (pH 6.0) buffer. The optimal pH for β-glucosidase activity in the crude cellulase cocktail was (pH 5.0) at 50 °C. Optimal cellulose hydrolysis using the crude cellulase cocktail occurred at longer incubation times, and higher substrate loads and enzyme doses. Cellulose hydrolysis with the A. japonicus VIT-SB1 cellulase cocktail and commercial cellulase cocktails resulted in glucose yields of 15.12 and 12.33 µmol/mL glucose, respectively. Supplementation of the commercial cellulase cocktail with 0.25 U/mg of β-glucosidase resulted in a 19.8% increase in glucose yield. [ABSTRACT FROM AUTHOR]

The search for microorganisms with potential for bioconversion of lignocellulose is now of immediate interest. Industrial waste is a source of various microorganisms. This paper describes results of the research of potentially lignocellulolytic actinobacteria isolated from activated sludge of the wastewater treatment plant of a pulp and paper mill located in Komi Republic (Russia). One strain of actinobacteria, AI2, was found to be sufficiently active in terms of degradation of lignocellulose-containing materials. Testing of the AI2 isolate demonstrated its ability to synthesize cellulase, dehydrogenase and protease to various extents. The AI2 strain was found capable of biosynthesizing cellulase to 5.5 U/ml. In case of solid-phase fermentation using treated softwood and hardwood sawdust, the content of main components changed most significantly in aspen sawdust: from initial concentration of 20.4% down to 15.6% for lignin, and from 50.6% down to 31.8% for cellulose. In case of liquid-phase fermentation, the content of lignin components decreased significantly in the treated aqueous medium that contained lignosulfonates: from initial concentration of 3.6 g down to 2.1g. Taxonomic study of the AI2 strain of actinobacteria confirmed that it belongs to the rare Pseudonocardia genus of actinomycetes. Based on the results of 16S rRNA sequencing, the AI2 strain is most similar to the species Pseudonocardia carboxydivorans. [ABSTRACT FROM AUTHOR]

The biomass deconstructed by kraft process and the lignin dissolved in the black liquor are burned to generate energy in a pulp mill. This study used the black liquor from coffee parchment cooking, a residue from the coffee industry, to isolate kraft technical lignin. The parchment was subjected to the kraft pulping process to obtain pulps of kappa number 60 and 25, and the resulting black liquors were used for lignin extraction. Chemical characterization, elemental analysis and heating value of liquors and lignins were performed, as well as FTIR and Py-CG-MS analysis of lignins. The cooking provided liquors with similar characteristics, with lignin content of 31.67 and 32.63% for kappa 60 and 25 liquors, respectively. The extractions resulted in high purity lignin (92.35% for K#60 lignin and 93.96% for K#25 lignin). The higher heating values were 23.8 and 25.4 MJ/kg for K#25 and K#60 lignins, respectively. FTIR analysis showed characteristic peaks of lignin. Through Py-GC-MS, it was possible to observe the slight predominance of guaiacyl-type lignin, which can be an advantage depending on the application. It is possible to extract lignin from the black liquor obtained from the coffee parchment pulping to generate products with high-added value. [ABSTRACT FROM AUTHOR]

The uses of kraft lignin (KL), obtained from the black liquor (BL) in the pulping process, allow the production of activated carbon (AC), a product with high added value in the pulp mill. The AC can be used in three different sectors in a cellulose pulp mill: sectorial treatment of the cellulosic pulp bleaching filtrates; wastewater treatment; and in the treatment of water received by the mill. Thus, this article considers the steps in the production of AC, their types, and the advantages and challenges of its use in the kraft cellulose pulp mill as well as in other industries. [ABSTRACT FROM AUTHOR]

The best way to understand the environmental status of a certain region involves thorough non-target analysis, which will result in a list of pollutants under concern. Arkhangelsk (64° 32′ N 40° 32′ E, pop. ~ 344,000) is the largest city in the world to the north of the 60th parallel. Several industrial enterprises and the "cold finger" effect represent the major sources of air contamination in the city. Analysis of snow with comprehensive two-dimensional gas chromatography–high-resolution mass spectrometry allows detecting and quantifying the most hazardous volatile and semivolatile anthropogenic pollutants and estimating long-term air pollution. Target analysis, suspect screening, and non-target analysis of snow samples collected from ten sites within the city revealed the presence of several hundreds of organic compounds including 18 species from the US EPA list of priority pollutants. Fortunately, the levels of these compounds appeared to be much lower than the safe levels established in Russia. Phenol and dioctylphthalate could be considered as the pollutants of concern because their levels were about 20% of the safe thresholds. ChromaTOF® Tile, MetaboAnalyst software platform, and open-source software protocols were applied to process the obtained data. The obtained clusterization results of the samples were generally similar for various tools; however, each of them had certain peculiarities. Bis(2-ethylhexyl) hexanedioate, benzyl alcohol, phthalates, aniline, dinitrotoluenes, and fluoranthene showed the strongest influence on the clusterization of the studied samples. Possible sources of the major pollutants were proposed: car traffic and pulp and paper mills. [ABSTRACT FROM AUTHOR]

The possibility of producing fluffed pulp from hardwood raw material by an alternative technology comprising milling of pulp cloth in a stream of air (aerodynamic method) and of creating ecologically safe alternative technologies for manufacturing pulp intermediate was studied. [ABSTRACT FROM AUTHOR]

Nowadays, lignin is a byproduct of the agricultural and cellulose pulp mill. Lignin is a sustainable, renewable raw material alternative to petroleum‐based chemicals, mainly for the benzene–toluene–xylene (BTX) production of commodities and the sequential secondary, tertiary and manufactured products in the petrochemical industry. It can be mass produced and is used for renewable energy biorefinery or high‐value‐added products. This review aims to outline the important lignin depolymerization technologies and the feasibility of imposing these transforming technologies on a large scale. Finally, this review examines the market prospects for BTX, revealing its R&D progress. However, the harmful effects of BTX and unfavorable conditions resulting from the COVID‐19 pandemic comprise roadblocks to its growth. However, the increasing use of biobased BTX is expected to open new market opportunities. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Rapid degradation of pulping and papermaking wastewater in a pulp and paper mill is crucial for recycling purposes yet challenging to achieve. The purpose of this research is to provide a technical guide for the ozone degradation treatment process of pulp and paper mill wastewater and to explore the reaction mechanism of dissolved and colloidal substances (DCSs). This study is vital for effectively treating pulp and paper mill wastewater through ozonation. In the catalytic ozonation process to treat pulp and paper mill wastewater, a polyurethane sponge loaded with titanium dioxide was used as a catalyst. The optimal process conditions were determined to be 8 min of treatment time, a 16 mg/L ozone concentration, pH 9, and a 7.5% catalyst filling ratio. The COD reduction under these conditions is approximately 52%. The catalytic ozonation system, according to the FI-IR and GC-MS analyses, could degrade the large-molecule volatile organic compounds in the raw wastewater into small-molecule substances. Furthermore, the relative content of common DCSs in paper wastewater, such as palmitic acid and stilbene, could be reduced. The catalytic ozonation system is more effective for treating refractory organic compounds and has a higher COD reduction than the ozonation system. [ABSTRACT FROM AUTHOR]

The development of lignin-based admixtures (LBAs) for cement-based composites is an alternative to valorizing residual lignins generated in biorefineries and pulp and paper mills. Consequently, LBAs have become an emerging research domain in the past decade. This study examined the bibliographic data on LBAs through a scientometric analysis and in-depth qualitative discussion. For this purpose, 161 articles were selected for the scientometric approach. After analyzing the articles' abstracts, 37 papers on developing new LBAs were selected and critically reviewed. Significant publication sources, frequent keywords, influential scholars, and contributing countries in LBAs research were identified during the science mapping. The LBAs developed so far were classified as plasticizers, superplasticizers, set retarders, grinding aids, and air-entraining admixtures. The qualitative discussion revealed that most studies have focused on developing LBAs using Kraft lignins from pulp and paper mills. Thus, residual lignins from biorefineries need more attention since their valorization is a relevant strategy for emerging economies with high biomass availability. Most studies focused on production processes, chemical characterizations, and primary fresh-state analyses of LBA-containing cement-based composites. However, to better assess the feasibility of using different LBAs and encompass the multidisciplinarity of this subject, it is mandatory that future studies also evaluate hardened-sate properties. This holistic review offers a helpful reference point to early-stage researchers, industry professionals, and funding authorities on the research progress in LBAs. It also contributes to understanding the role of lignin in sustainable construction. [ABSTRACT FROM AUTHOR]

The pulp industry is a high natural resources consumer and has a large polluting potential. The pulping sector with the most effluent generation is the bleaching plant. Based on the need of water consumption reduction, this research aimed to evaluate the treatment of the alkaline effluent from an EP-stage bleaching plant and the white water from drying machine using ultrafiltration membranes in order to enable the reuse of the permeate in the process. An ultrafiltration pilot plant was used. Laboratory analyses were performed for the feed, permeate and retentate. Flux and transmembrane pressure (TMP) data were obtained from the pilot plant database. There were an average color and COD removals of 38 % and 39 %, respectively, for the EP-effluent and 58 % and 67 %, respectively for the white water; and a high turbidity and TSS removal (above 98 %) for both effluents. Substantial metals removal such as sodium, potassium, calcium, iron, magnesium and manganese was achieved. Some possibilities to reuse were considered: return to the water treatment plant, cooling of the digester bottom, equipment cooling, reuse in evaporation surface condensers. The use of ultrafiltration for the treatment of the alkaline effluent from the bleaching EP-stage and white water can be an interesting option. [ABSTRACT FROM AUTHOR]

Eight fungal strains (F1–F8) isolate from the sediment core and degraded wood of the Pulp and Paper Mill effluent and Phanerochaete chrysosporium are tested for different cellulolytic (CMcase, FPase, Xylanases) and lignolytic (lignin peroxidase) enzyme activity in pulp. F‐3 (Cryptococcus neoformans) strain shows higher enzyme activity compare to other fungi isolated from effluent. Weight loss, cellulose loss, and organic carbon contents are found maximum in F‐3 (C. neoformans) strain. Reducing sugar, protein content, and color removing potential are also higher in C. neoformans. The culture extract of F‐3 strain grows in presence of pulp fractionated into five protein fractions has indicated two fractions of molecular weight, 38,000 and 40,000 Da, having lignin peroxidase activity. Lignin peroxidase has optimum activity at pH 2–3 and temperature 20–30 °C, maximum activity at 6–48 mM veratryl alcohol concentration and 256 mM H2O2, however, sodium azide inhibits the enzyme activity. Different metals (CoCl2, HgSO4, CaCl2, SnCl2, FeSO4, CuSO4, and ZnSO4) also affect the lignin peroxidase activity. Characterization study is performed for significant analysis. [ABSTRACT FROM AUTHOR]

Carbon capture, utilization and storage (CCUS) have been projected by the power and industrial sectors to play a vital role towards net-zero greenhouse gas emissions. In this study, we aim to explore the feasibility of a global chemical industry that fully relies on CO2 as its carbon source in 2050. We project the global annual CO2 demand as chemical feedstock to be 2.2–3.1 gigatonnes (Gt), well within the possible range of supply (5.2–13.9 Gt) from the power, cement, steel, and kraft pulp sectors. Hence, feedstock availability is not a constraint factor for the transition towards a fully CO2-based chemical industry on the global basis, with the exception of few regions that could face local supply shortages, such as the Middle East. We further conduct life cycle assessment to examine the environmental benefits on climate change and the trade-offs of particulate matter-related health impacts induced by carbon capture. We conclude that CO2 captured from solid biomass-fired power plants and kraft pulp mills in Europe would have the least environmental and health impacts, and that India and China should prioritize low-impact regional electricity supply before a large-scale deployment of CCUS. Finally, two bottom-up case studies of China and the Middle East illustrate how the total regional environmental and health impacts from carbon capture can be minimized by optimizing its supply sources and transport, requiring cross-sectoral cooperation and early planning of infrastructure. Overall, capture and utilization of unabatable industrial waste CO2 as chemical feedstock can be a feasible way for the net-zero transition of the industry, while concerted efforts are yet needed to build up the carbon-capture-and-utilization value chain around the world. [ABSTRACT FROM AUTHOR]

Eco-chemical monitoring of the snow cover in the impact zone of a pulp and paper mill was carried out. Conditional impact zones of the mill were identified. The interannual variations in their area were shown. There was a more than 50% decrease in the area of impact zones after the reconstruction of the mill. It was estimated that the seasonal features of the wind regime significantly influenced the formation of a snow pollution plume. A calculation of air mass trajectories showed a probable area of displacement of emission components from the mill. A comparison of field data on the pollution dispersion obtained during the snow cover study with data on the wind direction and air mass transport confirmed the consistency of these data. [ABSTRACT FROM AUTHOR]

Slaker grits (SG) and biomass fly ash (BFA), two waste streams generated in the pulp and paper industry, are commonly disposed of in landfills, a practice with a high economic and environmental burden. In this work, their individual valorization as fillers in a commercial screed mortar formulation was evaluated in order to achieve a more sustainable management practice. The waste streams were characterized in terms of true density, particle size and morphology, and chemical and mineralogical composition. The influence of their incorporation amount (5.0, 7.5, and 10.0 wt.% of the total solids) and pre-treatment (sieving and grinding) on the fresh (workability) and hardened state (density, water absorption by capillarity, and flexural and compressive strength) properties of the mortars were assessed. The results show that the addition of 10.0 wt.% of the SG after milling and sieving (<75 µm) and 7.5 wt.% of BFA in the as-received condition, or up to 10.0 wt.% after grinding and sieving (<63 µm), allowed for the production of mortar samples with properties within the recommended specifications and that were resistant to 25 consecutive freeze-thaw cycles. This waste valorization route could represent an economic benefit of up to 8.85 €/tmortar and 2.87 €/tmortar for mortar, and pulp and paper companies, respectively. [ABSTRACT FROM AUTHOR]

The process of phosphorus recovery from wastewater treatment plants by vivianite crystallization is briefly described. The influence of microorganisms, pH value and oxidation-reduction potential, iron source, temperature, and organic matter on the crystallization process of vivianite is systematically summarized. The research progress of the application of vivianite crystallization method in practical wastewater treatment plants is summarized. The feasibility, problems and improvement measures of the engineering of vivianite crystallization method are analyzed, and the future research direction is prospected, in order to provide reference for the technological research and engineering application of phosphorus recovery by vivianite crystallization method. [ABSTRACT FROM AUTHOR]

In the present study, a kinetic model has been developed to predict the chemical oxygen demand (COD) removal efficiency of Fenton process for the treatment of pulp and paper mill (P&P) wastewater. In order to investigate the effects of main parameters including Fe(II) dosage, H2O2 dosage, and pH, 45 experiments have been carried out at three levels for each parameter, and thus COD removal efficiency has been obtained. The Fenton process was simulated by using 10main reactions, and the model was solved numerically according to a specific algorithm. All the pollutants in the P&P wastewater were assumed to be a pseudo-material, andapparent kinetic constant (k**)was calculated using a developed iterative method. The results of the numerical model indicated that the proposed model had a great potential to predict COD removal efficiency for P&P wastewater by Fenton in comparison to the first and second-order kinetic models. Accordingly, R-squared (R2), Root Mean Square Error (RMSE), and Mean Relative Error (MRE) of the numerical kinetic model were 0.93, 4.296 × 10−7, and 0.035, respectively, implying remarkable accuracy of the numerical model. Furthermore, at the optimum point of Fenton process,which was pH: 3,[H2O2]:0.015 Molar, and [Fe(II)]: 0.015 Molar, the COD removal efficiency of P&P wastewater reached 78%. As the basis of the numerical model was established according to mechanisms of Fenton process, the results demonstrated the great performance of the advanced kinetic model in the estimation of the COD removal efficiency, the behaviour of effective parameters such as pH, H2O2, and Fe(II) along with their effects on k**, and Fe(III) accumulation during Fenton process. [ABSTRACT FROM AUTHOR]

This article discusses the benefits of upgrading the pump seal casing in a US pulp and paper mill. Vertical pumps often rely on packing instead of mechanical seals, but packing has disadvantages such as the need for continuous adjustment and fluid leakage. The mill decided to upgrade to a seal casing design to address reliability and environmental concerns. The seal casing design provides advantages such as minimal maintenance, zero leakage above the baseplate, and improved safety. The mill successfully made the upgrade, eliminating leakage and improving the lifespan of aboveground components. [Extracted from the article]

Of the various waste and side streams created in a kraft pulp mill, the biological sludges from the wastewater treatment plant are some of the most problematic to handle. Incineration is becoming a common solution as landfilling is no longer permitted by legislation in many countries, but this is also problematic due to the high moisture content, poor drying characteristics, and high ash content in the solids. This study evaluates the technical potential of mild hydrothermal carbonization (HTC) at 160 °C for 3 h to improve the energy efficiency of on-site incineration as a biosludge handling method. HTC treatment transforms wet organic substrates into a hydrophobic carbonaceous material (hydrochar). The heating value and elemental composition of both the sludge and the hydrochar product were analyzed. Based on this, a hydrothermal carbonization model developed earlier was adjusted for the feedstock, and process integration modelling performed to evaluate the performance impact on the power and heat generation at the mill. The results indicate that if the alternative is combustion in the power boiler, HTC pre-treatment could allow a significant increase in power generation. If the sludge is combusted in the recovery boiler, a practice often avoided in order to not introduce non-process elements to the chemical recovery cycle but sometimes necessary due to, e.g., absence of a power boiler, a much smaller increase is obtained. The increase is smallest if the freed evaporator plant capacity cannot be utilized for increasing the firing liquor dry solids content. [ABSTRACT FROM AUTHOR]

Green liquor solution (GLS) is waste pollutant from pulp and paper mills. Causticization process is a common treatment method for GLS, which is energy intensive and environmentally unsafe, because of high operating cost, and solid waste generation. We reported synergetic effect of titanium dioxide nanoparticle (TiO 2) incorporated sulfonated PEEK, on the performance cation exchange membrane (CEM), for producing NaOH from industrial GLS by electro-electroldiaysis (EED). Reported composite CEM was studied for morphology, physicochemical, electrochemical properties. The counter-ion transport number, stability and antifouling properties of CEM were significantly improved after the addition of TiO 2 nanoparticles in the sulfonated PEEK membrane matrix. Two compartment EED cell (active membrane area: 66 cm2) was used to perform the experiments for producing NaOH using industrial GLS at 60 mA·cm−2 constant current density. The reported results shed light on production of NaOH along with prevention of sulfur scaling in treatment of wood based pulp and paper mills GLS stream. The modified membrane named SPK-T-5 (5 wt% of TiO 2) by utilizing containing sulfonated polymer matrix outperforms an increasing trend of NaOH production along with notable sulfur antifouling. The obtained research outcomes are expected to be a valuable source for NaOH production with the aim of zero solid discharge practice for pulp and paper mills. [Display omitted] • TiO 2 loaded polymeric cation exchange membrane for electro-electrodailysis. • Adequate membrane stability for treatment of industrial green liquor. • Pre-optimized current density and flow rate for maximum NaOH production. • One step NaOH production from green liquor with "zero liquid effluent". • Sustainable environment friendly approach over conventional multistep process. [ABSTRACT FROM AUTHOR]

This work provides a critical review of the potential of integrating green methanol production processes in pulp mills. It identifies the current challenges, available synergies and future trends, whilst considering the inside perspective of current experts on implementing biorefinery processes and projects in this industry. The performed analysis shows that green methanol can be a key material in various decarbonization strategies, and pulp mills are natural frontrunners to establish production plants due to their suitability to implement biorefinery processes and the local existence of large flowrates of biogenic CO2. Three potentially integrable pathways were identified and discussed: (i) e-methanol from captured CO2 and green H2, (ii) biomethanol from the gasification of Kraft pulping byproducts and (iii) biomethanol from the purification of stripper off gases. However, several challenges and drawbacks must be tackled, such as insufficient low-cost renewable electricity, transmission grid issues, complex process implementation, difficult synergy seizing, low maturity of the technology start-to-end chain and unclear legislation, that ultimately result in excessive production costs and lack of stakeholder's confidence. The inability to address these challenges can lead to the failure or postponement of projects, consequently reducing the potential role that green methanol and hydrogen strategies can have towards full energy decarbonization. [ABSTRACT FROM AUTHOR]

This study investigated the color removal efficiency of pulp and paper mill wastewater using residual eucalyptus wood as a method to minimize the solid wastes generated from pulp and paper processes. The activated carbon used in this study as the color adsorbent was produced from residual eucalyptus wood. The carbon was activated with phosphoric acid and carbonized in a furnace at 500°C for 60 min. Effects of types and amounts of activated carbon on color removal efficiency were evaluated. Three types of solid wastes, consisting of wood chip, bark, and mixed wood (wood chip:bark, 1:1), were investigated at a loading of 1, 3, 5, and 7 g/100 mL under contact times of 30, 60, 90, and 120 min. The results showed that 7 g of wood chip activated carbon/100 mL under all contact times gave color removal efficiency of 94-97%. However, the highest adsorption capacity of 216 ADMI/g occurred at 1 g of adsorbent used. Freundlich isotherms were satisfactorily fitted to experimental data for the best condition with high correlation coefficients. The color removal efficiency depended on surface area, pore volume, structure, and characteristics of the activated carbon. [ABSTRACT FROM AUTHOR]

The catalytic ozonation processes with continuous-flow reactors were used for pulp and paper mill wastewater treatment. [Display omitted] • The pulp and paper wastewater is treated effectively by catalytic ozonation with continuous-flow reactor. • The porous ceramsite catalytic ozonation can be used for continuous-flow process. • The porous ceramsite catalyst is continuously and stably operated for 30 days. • The lowest E EO value is reached at the O 3 dosage of 15 g/L. • The degraded or transformed organic pollutants present in PPMW by O 3 alone system and catalytic ozonation system were identified. The pollutants in wastewater can be degraded effectively by heterogeneous catalytic ozonation due to the production of hydroxyl radical (•OH) with strong oxidation power. For the natures of low weight, large specific surface area, excellent physical strength and stable chemical characteristics, the porous ceramsite was chosen for catalytic ozonation of wastewater in the present study, and the practical application parameters of the system were investigated for the actual pulp and paper mill wastewater (PPMW) in the continuous-flow reactor including temperatures, feeding flow rate, O 3 flow rate and O 3 dosage. The optimum experimental conditions were obtained (T = 25 ℃, feeding flow rate = 0.25 L/min, O 3 flow rate = 0.5 L/min, O 3 dosage = 15 g/L) for the process of catalytic ozonation. The results show that the effluent concentration of COD decreases from about 200 mg/L to 10 mg/L, namely the removal efficiency is about 95 %. The stability of the catalyst over time was tested in the continuous-flow reactor for 48 days, confirming that the porous ceramsite exhibits good performance in 30 days. The reusability of the catalyst was studied after the used catalyst was washed with Milli-Q water and ethanol, exhibiting good catalytic activity of the regenerated catalyst in three cycles. The fluorescent excitation-emission matrix (EEM), UV–vis analysis and GC–MS analysis were used for analyzing the organic pollutants in raw PPMW and after treatment. These results indicate that the process of catalytic ozonation with porous ceramsite has a high treatment efficiency on PPMW, and the continuous-flow reactor can be more practically used for a full-scale community PPMW application at a mill level. [ABSTRACT FROM AUTHOR]

This paper presents the concept of an alkali-O2 oxidation process for producing lignin dispersants in a feasible manner at a kraft pulp mill. The oxidation process uses O2 gas to increase the anionic charge of lignin and the final oxidised lignin can serve as a concrete plasticiser or versatile dispersant. The integrated process provides several benefits for lignin recovery, the following lignin oxidation, and recycling of chemicals. Firstly, CO2 precipitated kraft lignin can be used without a sulphuric acid washing step. This simplifies the lignin recovery and no excess sulphur is introduced into mill cycle. As the unwashed lignin is alkaline in nature, the need for fresh alkali in the lignin oxidation is reduced. Moreover, oxidised white liquor, readily available in the mill, can be applied as a partial source of alkali. Finally, membrane filtration of the oxidised lignin solution enables the recirculation of sodium and sulphur back to the chemical cycle and provides a concentrated lignin product. Based on a simulation study, this novel concept significantly decreased the need for purging fly ash at the mill when compared to conventional lignin recovery. It was also demonstrated that the novel lignin dispersants can compete with the tested commercial oil-based plasticisers. [ABSTRACT FROM AUTHOR]

Wood is the most expensive fraction in the pulp production costs. Therefore, strategies for increasing wood quality such as faster growth, higher wood basic density and lower lignin content are drivers to pulp mills. The cultivation site as well as the eucalypt clones influence the wood quality, which, in turn, affects the pulp production performance. Thus, this work aims to evaluate the effect of the site on the wood quality for the pulp production. Three eucalypt clones from five different sites in Brazil were used in this study. These samples were selected aiming to represent a gradient of environmental stress. It was possible to observe a reduction in the content of extractives and lignin and an increase in the content of glucans in the sites with less environmental stress, reflecting in the production of pulp with less effective alkali demanded (reduction of 13.5 %) and an increase of 10.5 % in the kraft pulp screened yield. MAIP values of 22.7 ton/ha/year were obtained in the sites with less environmental stress, presenting a lower specific wood consumption. Through the production indicators, it was observed that the C1 clone is more adaptable to the regions of greater environmental stress than the other clones analyzed. [ABSTRACT FROM AUTHOR]

[Display omitted] • A total of 20 different paper sludges were investigated. • A wide range of biomethane potentials was determined. • Inhibiting substances for some paper sludge were identified. • Co-digestion resulted in methane yield increase of 5–10%. • The possibility of anaerobic co-digestion could be demonstrated. In this work, the feasibility of the anaerobic digestion of paper sludge as a co-substrate in anaerobic digestion mechanical–biological treatment (MBT) plants is investigated. In the first phase, the biochemical properties, biomethane potential (BMP), and pollutant contents of 20 different industrial paper sludges are determined. Following the general evaluation in the BMP tests, the second phase of the project involves the semi-continuous co-digestion of six paper sludges in continuous stirred reactors (CSTR). Paper sludges are categorized according to their origin within the pulp and paper mills: Deinking Sludge (DS), Primary Sludge (PS) and Biological Sludge (BS). The analysis of potentially inhibiting elements shows that the concentrations of chlororganic compounds, mineral oil and some heavy metals are highest in DS, while the mean heavy metal loads in all paper sludges are relatively low compared to other industrial sludges. Large differences in total solids (TS) and volatile solids (VS) contents are observed among the different paper sludges investigated, with DS having the highest TS due to the high inorganic contents. The BMP of the investigated sludges ranges from 90 to 355 NL CH 4 kg−1 VS. In subsequent semi-continuous co-digestion experiments simulating MBT conditions, three DS and two fiber sludges (a mixture of PS and BS) show good methane generation rates, while one fiber sludge causes inhibition and indicates an increase in viscosity. In general, co-digestion of paper sludge in anaerobic digestion MBT plants can be a viable option for energy production and also facilitates a safe disposal of the paper sludge digestates. [ABSTRACT FROM AUTHOR]

In this study, the electro-Fenton process (with response surface methodology as an experiments design and optimisation technique) was applied to evaluate the effects of five independent variables on the chemical oxygen demand (COD) and colour removal from paper pulp wastewater (PW). The parameters were statistically optimised under response surface methodology. The optimum conditions for 98.2% of COD and 96.8% of colour removal experimentally were at a reaction time of 30 min, current density of 79.9 mA/cm2, pH of 6.9, hydrogen peroxide (H2O2)/PW volume ratio of 1.7 ml/l, hydrogen peroxide (H2O2)/ferrous ions (Fe2+) molar ratio of 1.6, electrode consumption of 0.1 (g/l) and energy consumption of 1.3 (kWh/m3). In the next step, the filtration process was carried out on the treated effluent obtained at the optimal conditions. Then, this was mixed with activated sludge in a ratio of 1 : 10; 99.9% of COD and colour removal was found after 150 and 60 min, respectively. [ABSTRACT FROM AUTHOR]

• Quality variation of wood ash in pulp paper mills impedes uses. • Ash qualities vary from mill to mill even in the same mill from one ash to another. • Some wood ash properties are interrelated and can be estimated from each other. • Segregation of wood ash at the source can reduce ash quality variations. • Segregated wood ash has potential uses in soil amendment, construction, etc. Despite being a wood-derived biomaterial, wood ash generated by Canadian pulp paper mills (PPM) is generally landfilled. This is mainly because of the heterogeneous nature of ash, variations in ash quality and differences in the requirement of ash applications. Unlike limited past work on ash analysis for environmental compliance purposes for specific mills, a comprehensive database of ash quality for the PPM has been developed. Samples of three ash streams, bottom ash (BA), multiclone ash and electrostatic precipitator (ESP) ash, were collected. They were analyzed for physical, chemical and engineering properties of relevance to potential ash uses in areas such as the construction industry, compost production, soil amendment and waste stabilization/ solidification. Results show that the ash quality varied widely from one mill to another. Even within a mill individual ash streams varied substantially in properties. For example, the unburned carbon, a unique parameter for wood ash, in multiclone ash could be over twice the amount in the ESP ash. It is suggested that the traditional definition of fly ash (FA) could be refined to multiclone ash and ESP (or baghouse) ash thereby promoting the source segregation concept for the various ash streams produced at a mill. It is believed that the ash segregation approach, whereby ash sub-streams are kept separate to preserve their quality for specific uses, will minimize heterogeneity and quality variations of ash. This study will not only help divert wood ash away from landfills in favour of beneficial applications but also reduce carbon footprint of a mill. [ABSTRACT FROM AUTHOR]

The article presents the emerging forest bioeconomy as an integrated, multi-product industrial ecosystem, where the traditional pulp mills allocate the use of side streams to independent biochemical companies manufacturing bioproducts in the vicinity of the pulp mills. Topics include the biochemical benefit from the proximity by receiving wood-based side streams at lower costs, and at the same time, and the pulp mills benefit from having a new source of revenue from selling side streams.

Paper and pulp mills use a huge quantity of water in the manufacturing process and release a substantial quantity of salts in the effluent. The use of industrial effluents for irrigating crops due to the nutrient content in arid zones is under practice. The long-term use of paper and pulp mill effluent as a source of irrigation accumulates salts in the soil surface and rhizospheric zone. In this study, halophytes, namely Sesuvium portulacastrum, Salicornia brachiata, and Suaeda maritima were evaluated for their phytodesalination potential in paper and pulp mill effluent irrigated soil. Among these Sesuvium portulacastrum recorded the highest dry matter production (8.21 g pot-1), and the sodium accumulation was 6.7% greater than S. brachiata on 120th day. Furthermore, the soil EC was also 7.7 % lower in pots cultivated with S. portulacastrum than pots cultivated with S. brachiata. Hence, Sesuvium portulacastrum could effectively be used to phytodesalinate saline soils and ensure the sustainable cultivation of crops using paper and pulp mill effluent. [ABSTRACT FROM AUTHOR]

Each year, 50 to 70 million tonnes of lignin are produced worldwide as by-products from pulp industries and biorefineries through numerous processes. Nevertheless, about 98% of lignin is directly burnt to produce steam to generate energy for the pulp mills and only a handful of isolated lignin is used as a raw material for the chemical conversion and for the preparation of various substances as well as modification of lignin into nanomaterials. Thus, thanks to its complex structure, the conversion of lignin to nanolignin, attracting growing attention and generating considerable interest in the scientific community. The objective of this review is to provide a complete understanding and knowledge of the synthesis methods and functionalization of various lignin nanoparticles (LNP). The characterization of LNP such as structural, thermal, molecular weight properties together with macromolecule and quantification assessments are also reviewed. In particular, emerging applications in different areas such as UV barriers, antimicrobials, drug administration, agriculture, anticorrosives, the environment, wood protection, enzymatic immobilization and others were highlighted. In addition, future perspectives and challenges related to the development of LNP are discussed. • Synthesis methods of various lignin nanoparticles are reviewed. • Physico-chemical characterizations of LNPs are discussed. • Promising application of LNPs in different areas is summarized. • Future perspectives and challenges related to the development of LNP are discussed. [ABSTRACT FROM AUTHOR]

In this study, the viability of acetylation in cellulose fibers waste (CFW) from pulp and paper mill sludge was investigated in comparison to bleached cellulose fibers (BCF). Four acetylation methodologies were applied. The inorganic ash composition of the CFW was determined by Energy Dispersive X-ray Spectrometry (EDS). The Degree of substitution (DS) of the acetylated fibers and their characterization using Fourier Transformed Infrared (FT-IR), X-ray diffraction (XRD), Thermogravimetric analysis (TGA), and Scanning electronic microscopy (SEM) were carried out. Results showed that the different acetylation methods are not effective for the esterification of CFW largely due to a high mineral content in their composition. The acetylation promoted the removal of the inorganic content in the CFW resulting in low efficacy levels. In BCF, higher efficiency levels were achieved, varying according to the methods. The different acetylation methods showed an efficiency range from 0.02 to 1.76 depending on the type of fiber. [ABSTRACT FROM AUTHOR]

Producing sugar from lignocellulosic biomass is a promising resilient food solution to counter the near-total global failure of food production due to the agricultural collapse that would likely follow an abrupt sunlight reduction catastrophe such as a nuclear winter, a supervolcanic eruption, or a large asteroid or comet impact. This study examines how quickly edible sugar production could be ramped up globally by repurposing pulp and paper mills, sugarcane biorefineries, corn biorefineries, and breweries for lignocellulosic sugar production. A sub-unit component comparison to the NREL 2017 Biochemical Sugar Model indicates that 84%, 65%, 37%, and 39% of ISBL unit components are present, respectively. Fast construction methods were studied to analyze how this and other industrial foods could be rapidly leveraged in a catastrophe. Results suggest that the world’s current sugar demand could quickly be fulfilled by repurposing pulp and paper mills for lignocellulosic sugar production, given 5 months of production ramp-up and 24/7 construction. This method could reduce construction time to an estimated 32% of the original at an increased labor cost of 1.47 times, resulting in sugar production beginning 5 months after the catastrophe at a retail cost of $0.82 USD/kg. This could not only contribute a significant share of the food requirement after the catastrophe (∼28% within the first year), but also be key to preventing global starvation between the time at which global food storages run dry and other resilient food solutions can scale up significantly. This study aims to serve as the basis for more comprehensive scenario analyses. More research is needed to characterize material and labor constraints to fast response in more depth; repurposing and fast construction pilot studies and food safety studies are recommended. [ABSTRACT FROM AUTHOR]

The production of fermentable sugars from lignocellulosic biomass is achieved by the synergistic action of a group of enzymes called cellulases. Cellulose is a long chain of chemically linked glucoses by β-1,4 bonds. The enzyme β-1,4-endoglucanase is the first cellulase involved in the degradation, breaking the bond of the amorphous regions. A β-1,4-endoglucanase enzyme with high activity was obtained from a Bacillus subtilis strain isolated from wastewater of a pulp and paper mill. Sequencing and bioinformatic analysis showed that the gene amplified by PCR consisting of 1407 nucleotides and coding for a β-1,4-endoglucanase enzyme of approximately 55 kDa. The open reading frame (ORF) encoding the mature endoglucanase (eglS) was successfully inserted in a modified cloning plasmid (pITD03) and into the pYD1 plasmid used for its expression in yeast. Carboxymethylcellulose (CMC) plate assay, SDS-PAGE, and zymogram confirmed the production and secretion by the transformed E. coli BL21-SI strain of a 39 kDa β-1,4-endoglucanase consistent with the catalytic domain without the cellulose-binding module (CBM). The results showed that the truncated β-1,4-endoglucanase had higher activity and stability. • A strain of Bacillus subtilis with endoglucanase activity was isolated from the wastewater of a pulp and paper mill. • The endoglucanase gene was inserted into a modified plasmid (E. coli) and into pYD1 (S. cerevisiae). • The endoglucanase in pYD1 is expressed with good activity in E. coli , being the first report of this finding. • A truncated recombinant endoglucanase is obtained and is very stable at pH (2-10) and temperature (30–55 °C). [ABSTRACT FROM AUTHOR]

[Display omitted] • Optimization study of Photo-Fenton and PDS/UV processes for BOD and COD removal. • Photo-Fenton process was able to enhance biodegradability. • PDS/UV process on the best condition only could maintain the biodegradability. • The operational cost of Photo-Fenton processes is much cheaper than PDS/UV process. The aim of this study is to provide an Advanced Oxidation Process (AOP) based solution to enhance biological treatment efficiency by improving biodegradability of wastewater. Photo-Fenton and Peroxydisulfate (PDS)/UV processes were selected in this study as a representative of hydroxyl and sulfate radical based AOPs. A central composition design (CCD) employed to optimize operational cost and BOD/COD ratio to determine optimal conditions for enhancing wastewater treatment efficiency. The study achieved a maximum COD removal of 71.5 % and increased wastewater biodegradability. Optimal conditions for Photo-Fenton process were DOD (H 2 O 2) 0.28, [Fe2+] 106.26 mg/L, and pH 2.32, costing 2.27 USD per 1 kg COD removed. For PDS/UV process, 75.5 % COD removal was achieved at a cost of 10.6 USD/1 kg removed COD. The PDS/UV process had higher COD removal than Photo-Fenton but did not improve wastewater biodegradability. Optimal conditions were DOD (PDS) 0.19, pH 6.68, costing 10.6 USD/1 kg COD removed. [ABSTRACT FROM AUTHOR]

In this study, the effects of thermal treatment at moderately low temperatures (T max : 525 °C) on the composition and properties of two distinct green liquor dregs (GLD) samples from two different pulp mills were investigated. This in-depth characterization was conducted with the aim of enabling the use of GLD as raw materials in cementitious applications (e.g., alkali-activated binders). The elemental composition of the GLD samples primarily comprised Ca, Mg, S, Na, and Mn. Analysis using x-ray diffractometry, an electron probe microanalyzer, and scanning electron microscopy revealed that calcite was the main crystalline phase, whereas layered double hydroxides with varying compositions constituted the primary amorphous phase. Characterization through Fourier-transform infrared spectroscopy and thermogravimetric analysis coupled with mass spectrometer analysis, indicated the loss of water and carbon during thermal treatment. Total organic carbon analysis showed that most of the removed carbon was organic, despite some remaining after thermal treatment at 525 °C. A leaching test was conducted to quantify the soluble Ca, Mg, Na, and K content, as well as pH variations. Overall, the findings suggest that thermal treatment enhances the potential of GLD samples for use in binder materials in the construction sector. [Display omitted] [ABSTRACT FROM AUTHOR]

• A new software addresses the rapid analysis of black liquor evaporation plants. • An intuitive interface with equipment widgets allows different plant configurations. • EVATool includes a dashboard for easy visualization of the main results. • Software validation including different plants examples was accurate and reliable. • EVATool provides insights for operational evaporation processes decision-making. The energy recovery capability of a kraft pulping process is crucial for its feasibility, and the evaporation process of black liquor is very important for a successful energy recovery since it is the first stage of the recovery system. Despite the apparent simplicity of the process, black liquor evaporation involves multiple evaporators and complex unit operations. Therefore, analyzing and simulating different operational scenarios is essential before proposing changes. A new software tool was developed to address the limited offer of specific software for analyzing black liquor evaporation plants. It focuses on fast analysis of these plants by estimating the heat transfer coefficient, steam consumption, steam economy, black liquor mass fraction between effects, and others. The tool was developed in Python and provides an interface resembling the supervisory system used by operators and offers equipment widgets for creating plant diagrams. EVATool also presents a dashboard for easy visualization of the main results. Software validation using examples of evaporation plants has confirmed its capability to simulate plants in different modes. In an industrial setting, the dashboard enables the comparison of simulated values with project indicators unavailable through operational instrumentation. While improvements are possible, this software shows great potential for industrial implementation, contributing to operational decision-making in daily operations of the evaporation process in pulp mills. [ABSTRACT FROM AUTHOR]

The results of the study of the condition of the territory and waste deposits of the Baikalsk Pulp and Paper Mill using radar and optical satellite data are presented. The Earth's surface deformations in the area of waste deposits are analyzed using the method of differential radar interferometry applied to the ALOS-2 PALSAR-2 L-band radar satellite data. By processing the C-band radar data from the Sentinel-1B satellite using the method of multitemporal SBAS interferometric measurements, two blocks are found in the study area, one of which is rising and the other one of which is subsiding. The difference between deformations over the period from 2017 to 2020 reached 17–19 mm. A significant correlation in determining waste water content between radar-backscatter intensity measurements (Sentinel-1B satellite) and optical data (Sentinel-2A/B satellites) using the NDWI water index is revealed. [ABSTRACT FROM AUTHOR]

Data from two thermo-mechanical pulp mills are collected to simulate the refining process using deep learning. A multilayer perceptron neural network is utilized for pattern recognition of the refining variables. Results show the impressive capability of artificial intelligence methods in refining energy simulation so that the correlation coefficient of 98% is accessible. A comprehensive parametric study has been made to investigate the effect of refining disturbance variables, plate gap and dilution water on refining energy simulation. The generated model reveals the non-linear hidden pattern between refining variables, which can be used for optimal refining control strategy. Considering the disturbance variables' effect in refining energy simulation, model accuracy could increase by 15%. Removing the plate gape from predictive variables reduces the simulation determination coefficient by up to 25% in both mills, while the mentioned value for removing dilution water is 9–17% in mill 1 and about 35% in mill 2. [ABSTRACT FROM AUTHOR]

Organic-rich pulp and paper mill sludge (PPMS) has the potential to become a renewable carbon source for producing alternatives to fossil-based product. In this work, PPMS treated by hydrothermal carbonization (HTC) was investigated based on its pyrolysis properties. The pyrolytic mechanism, kinetics data and product of the sample were studied using TG as well as pyrolysis tests in Py-GC/MS and a bench-scale reactor at 450, 550, and 650 °C. The results show that the thermal decomposition of feedstock is a two-stage reaction. The mean activation energy of the pyrolysis of HTC treated PPMS was estimated as 233.08 kJ/mol, which is higher than that of the pyrolysis of paper sludge reported before. The changes in enthalpies, entropies and Gibbs free energies from the reactants to the activated complex were estimated. The concentration of monocyclic aromatic hydrocarbons in the derived organic liquid fraction shows a positive correlation with the pyrolysis temperature. At 550 °C, the organic liquid fraction reached its highest yield at 13.7% with an oxygen level of 10.7 wt% and a higher heating value of 35.9 MJ/kg. The pyrolytic chars show that a molar ratio of O:C is less than 0.2, which shows potential for use as a carbon sink. • Multi-scale study of pyrolysis behaviour of paper sludge. • Δ H ǂ, Δ G ǂ, and Δ S ǂ of pyrolysis reactions are studied on TG. • Detailed components analysis of the pyrolytic vapor on Py-GC/MS. • Comprehensive evaluation of pyrolysis product from bench-scale reactor. [ABSTRACT FROM AUTHOR]

A lower shear strength and higher compressibility impose major challenges for construction on organic soils. Cementitious materials have been effectively used in the improvement of the engineering properties of mineral soils with low organic contents. However, limited studies have been devoted to the stabilization of the organic soils commonly encountered in forested regions in Canada. The present study investigated the effects of pulp mill fly ash (PFA) on the compressibility of a natural soil consisting of 26% organic matter. Fall-cone and oedometer tests were conducted on organic soil mixed with different PFA dosages (5%, 10%, 20%, 30%, 40%, and 50%), as well as on untreated soil samples. The mineralogical and microstructural aspects of PFA-treated organic soil were examined using scanning electron microscope and energy-dispersive X-ray spectroscopy techniques. The results suggest that when the organic soil was treated with PFA, its undrained shear strength and compressibility behavior were improved. Moreover, the potentially large settlement of organic soil can be reduced by the addition of PFA. The primary and secondary compression index (Cc and Cα, respectively) values decreased significantly when compared with the untreated organic soil, indicating that PFA stabilizers can effectively improve the creep behavior of organic soils. These findings indicate that the beneficial utilization of PFA for the stabilization of organic soils could be a practical step toward the environmentally sound management of this waste byproduct. [ABSTRACT FROM AUTHOR]