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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]

Black liquor (BL) bioconversion into valuable by-products is essential to develop a bioeconomy strategy; however, its furfural content hinders microbial fermentation activities. Hence, this study utilizes paper mill sludge (PMS) to provide extracellular enzymes, furfural-degrading microbial consortia, and electron donor required for promoting the BL hydrogenesis potential. Three up-flow anaerobic sequential batch reactors (UASBRs) are fed with PMS (UASBR1), BL (UASBR2), and PMS + BL (UASBR3) and operated in parallel at 15 min fill, 72 h reaction, and 4 h settling. The UASBR3 achieves the maximum volumetric H 2 of 1.483 ± 0.088 L/L/d and H 2 yield of 2.06 ± 0.12 mol/mol glucose, which drops by 88% in UASBR2 and 24% in UASBR1. The insufficient H 2 productivity values in UASBR2 could be due to a lack of nutrients availability (C:N = 440:1 and C:P = 19:1), higher furfural concentration (2116 ± 422 mg/L), and involvement of the butyrate fermentation pathway. The synergetic effect between PMS and BL overcomes these limitations and enriches the fermentation medium with Proteobacteria phyla (22.8%) and Acinetobacter sp. degrading furfural (6.1%). The microbial community at the phylum level (e.g., Proteobacteria , Firmicutes , and Actinobacteria) in UASBR3 maximizes the migration of electrons (e−eq = 9.34 ± 0.54%) towards efficient H 2 formation. [Display omitted] • Paper mill sludge (PMS) mitigated inhibitory effect of furfural in black liquor (BL). • PMS improved H 2 yield from the BL by 8.3-folds and accounted for 2.1 mol/mol glucose. • e– eq transferred to H 2 was 9.3% in the PMS:BL, 7.4% in PMS, and 1.27% in BL. • Acinetobacter degrading furfural (6.1%) was abundant with PMS addition. • Bacilli (8.9%) and Clostridia (5.4%) was dominant in the hydrogenesis of PMS:BL. [ABSTRACT FROM AUTHOR]

• Machine Learning to classify watermarked Italian paper. • XRF and FTIR spectroscopies to study late middle-aged Italian watermarked paper. • A new spatial-temporal approach to trace the local recipes and the geographical paper mills' production. • Bergamo and Bologna stand out as marked watermarked Italian paper mills. Manuscripts, illuminated codex, books, documents and letters are composite materials, traces of the past starting from the invention of the writing. In this context, dating is one of the most important information for document attribution, and watermarked papeItaly'smarkers for studying their time-spatial distribution. In the Late Middle Ages, Italy's most important centre of paper mill was located in the town of Fabriano (Marche region, Italy). Here, a selection of ten Italian Late Middle Ages watermarked papers belonging to the Corpus Chartarum Italicarum (Corpus of Italian papers) is characterised by elemental and molecular spectroscopies and collected data are analysed by Machine Learning (ML) to trace the local fabrication recipes and the geographical paper mills production. Data from portable X-ray fluorescence and Fourier transform infrared spectroscopy were analysed through Singular Vector Machine, Soft Independent Modeling of Class Analogy and Moving Blocks methods. This innovative ML spatial-temporal approach based on keeping the temporal variable fixed is used to find elemental benchmarks for classifying the watermarked Italian notarial catalogue of the Late Middle Ages finding differences in the local recipes and studying the homogeneity in the paper mills' production. Results show that watermarked paper from Northern Italy, from the town of Strozza, Piacenza and Bergamo , as well as Bologna, present a high elemental and molecular homogeneity, which indicates that the hand-made processing technique could be the same helped by the proximity of the three cities, starting point for technologies exchange or influence. No heavy metals are found in the watermarked paper and K, Ca, Fe and Zn are identified as elemental benchmarks. Finally, Ca, Ti, Mn, Cr and Fe are particularly present on the edges of the watermarked papers. [Display omitted] [ABSTRACT FROM AUTHOR]

This critique examines a review article in this journal on adsorption techniques for removing metal ions from wastewater. The article is marred by several flaws, including tortured phrases, miscitations, incoherent statements, and factual inaccuracies. These problems weaken the article's clarity and reliability, raising doubts about the authors' understanding of the subject. As a result, the review's credibility is compromised, limiting its value as a reliable resource for researchers. This critique highlights these issues, stressing the importance of accuracy and rigor in scientific writing. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of application rate (AR) of sodium lignosulfonate (MBL) and propionic acid (PRP) on high moisture alfalfa hay spoilage during storage and its nutritive value. Treatments (TRT; MBL and PRP) were applied at four AR: 0 (CON), 2.5, 5 and 10 g/kg (fresh basis) to alfalfa hay at 68.5 % dry matter (DM), packed into mini bales and stored for 33 d. Data were analyzed as a randomized complete block design (5 blocks) with a 2 TRT × 4 AR factorial arrangement. At d 33, DM losses were decreased by PRP at 5 and 10 g/kg ( x ¯ = 0.9), vs. CON (6.92) and MBL (6.63 ± 1.13 %). Visual moldiness (0–10 ranking) and mold counts were also decreased by PRP at 5 (2.4 and 5.30) and 10 g/kg (0 and 2.7) relative to CON (6.0 and 7.13) and MBL (5.85 ± 0.67 and 7.21 ± 0.31 log cfu/fresh g, respectively). Both TRT kept aNDF and ADF concentrations low at 2.5 g/kg AR (464 and 319) and to a greater extent at 10 g/kg (442 and 307), relative to CON (494 ± 8.1 and 333 ± 4.71 g/kg DM, respectively; P <0.001). Both TRT increased apparent in vitro DM digestibility at all AR relative to CON ( x ¯ = 543 vs. 501 ± 12.0 g/kg of DM, respectively), but, compared to MBL, PRP also increased the asymptotic maximal gas produced (188.4 vs. 179.7 ± 4.82 mL/g of incubated DM), the rate of gas production (9.46 vs. 8.72 ± 0.45 %/h), and total volatile fatty acids (117.5 vs. 114.8 m M , respectively; P <0.035), due to its greater concentration of nutrients. In conclusion, MBL failed to prevent spoilage of high moisture alfalfa hay while PRP was effective at doses >5 g/kg. However, MBL prevented the increase of aNDF and improved in vitro DM digestibility to the same extent as PRP, possibly due to its strong surfactant properties. • Sodium lignosulfonate (MBL) is a paper mill by-product with antimicrobial properties. • MBL failed to prevent spoilage of high moisture alfalfa hay mini bales. • In vitro dry matter digestibility was improved in hay treated with MBL. • The strong surfactant properties of MBL warrant further exploration as a preservative. [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]

• 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]

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]

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]

In recent years in India, fly ash-lime-gypsum (FaL-G) brick production has been adversely affected by the scarcity of fly ash and lime. Consequently, the current study aims to mitigate this problem. It delves into leveraging incinerated paper mill sludge ash (IPMSA) as a supplement to fly ash and lime in FaL-G brick production, aiming to present an eco-conscious alternative to conventional burnt clay bricks. It focuses on two blends: blend 1, replacing fly ash with IPMSA (2.5–30 wt%), and blend 2 substituting lime entirely with IPMSA (2.5–15 wt%). A thorough material analysis preceded brick manufacturing, involving techniques like energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, thermogravimetry differential thermal analysis, scanning electron microscopy, and X-ray diffraction spectroscopy. Subsequent tests evaluated compressive strength, water absorption, weight density, percentage of voids, initial rate of suction and chemical resistance of the resulting bricks. According to the XRD results, the higher IPMSA levels didn't induce any phase transformation. Remarkably, bricks incorporating IPMSA in blend 1 (2.5–20 wt%) and blend 2 (2.5–7.5 wt%) met the mechanical properties specified for 'class 10' bricks according to Indian and ASTM standards. Incorporating IPMSA increases the porosity of bricks, making them lighter. This aids in minimizing construction expenses by reducing labour and transportation costs as well as lowering expenditure on foundation construction. This sustainable approach efficiently uses resources, reduces landfill wastes, shows potential for industrial-scale production, making eco-friendly bricks a promising alternative to traditional methods and promoting greener construction practices. • Ecofriendly FaL-G bricks were developed using incinerated paper mill sludge ash (IPMSA). • Reusability of IPMSA in FaL-G brick production poses both economic and environmental benefits. • Use of IPMSA in FaL-G brick production reduces landfill waste and addresses waste management issues. • IPMSA is suitable for up to 20 wt% for fly ash and 7.5 wt% for lime in FaL-G brick production, meeting relevant standards. [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]

The co-pyrolysis of paper mill sludge (PS) and biomass has attracted significant attention due to its potential for simultaneous resource utilization and waste disposal. In this work, the co-pyrolysis of PS with corn stover (CS) was carried out in a fixed bed reactor to investigate the effect of temperature and PS to CS ratio on the product characteristics. A comparison between the experimental and calculated values of product yield and composition was performed to obtain a deeper understanding of the synergistic interactions. The results exhibited a positive synergistic effect on bio-oil production at lower CS proportions with higher temperatures. Higher temperatures and lower CS proportions were favorable for the formation of aromatics (up to 45.03%) in co-pyrolysis, while the synergistic interactions promoted the production of phenols and exhibited an inhibitory effect on aromatics production. The interactions also inhibited H 2 but promoted CO production due to the enhanced decarbonylation of co-pyrolysis intermediates in the presence of PS internal minerals. Additionally, the characterization of biochars indicated an increasing degree of aromaticity with higher temperatures and CS proportions. The synergistic interactions at higher temperatures facilitated the development of pore structures in the biochar, especially micropores. This study provides valuable insights into the relationship between parameters, products, and synergies in the co-pyrolysis of PS and biomass wastes. [Display omitted] • A comprehensive study on the co-pyrolysis of paper sludge and corn stover was conducted. • Lower corn stover ratios with higher temperatures jointly promoted bio-oil yield. • The formation of phenols and CO was synergistically enhanced during co-pyrolysis. • Higher temperatures facilitated the development of micropores in the biochars. [ABSTRACT FROM AUTHOR]

This study optimizes a novel surfactant-assisted green liquor dregs (GLD) pretreatment of paper mill sludge (PMS), both of which are wastes from the kraft pulping industry, using a combined Response Surface Methodology (RSM) design. Optimized conditions give a maximal reducing sugar release of 16.38 g/L. A substantial reduction in heavy metals aluminum, chromium, cobalt, arsenic, lead, and copper after pretreatment illustrates the enhancement of substrate digestibility by reducing toxic elements. Separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) for hydrogen production are assessed. SSF produced a hydrogen yield of 3.72 mL/g, displaying a 36.26% increase from pretreated PMS compared to SHF. These findings provide insights into possible methods of reducing process duration, energy input, and costs incurred with waste disposal within the paper industry. Furthermore, improved hydrogen yield using an SSF process demonstrates the potential beneficiation of pulp and paper GLD and PMS wastes. • A novel surfactant-assisted GLD pretreatment of PMS developed. • An optimal reducing sugar release of 16.38 g/L was obtained. • Novel pretreatment protocol achieved significant heavy metal reduction. • SSF hydrogen production from pretreated PMS increased hydrogen yield by 36.26%. [ABSTRACT FROM AUTHOR]

[Display omitted] • The optical pure l -lactic acid (99.5%) can be produced by non-engineered Bacillus. • Paper mill sludge with low ash content benefits cellulase enzyme production. • The use of paper mill sludge as feedstock is cost-effective. • On-site enzyme production ensures economic viability. Paper mill sludge (PMS) raises critical environmental issues due to its disposal problem, but its high sugar content and well-dispersed structure make it a great feedstock for biochemical production. The technical feasibility of integrating cellulase enzyme production into lactic acid (LA) fermentation from PMS was investigated in this study. The low ash content of PMS suggests a great potential for cellulase production. The enzyme produced using PMS without any treatment gave an activity of 7.8 FPU/ml, a performance comparable to the commercial enzyme, Cellic CTec 2. The LA yield from PMS with in-house enzyme was 64.7% and 73.7% at the enzyme loading of 10 and 15 FPU/g-glucan, respectively. The LA obtained was optically pure L- isomer with over 99% purity. The optimal condition of LA production by Bacillus coagulans was found to be 50 °C and pH 5.3 (with 50 g/L CaCO 3). The nutrient effect of yeast extract (YE) and corn steep liquor (CSL) was substrate dependent, and CSL could substitute YE as an inexpensive nutrient when using PMS as a substrate. [ABSTRACT FROM AUTHOR]

• The application of PVDF UF membrane in pilot secondary effluent treatment from paper mills was studied. • Pore blockage and cake deposition were found to be the major fouling mechanism. • PVA-217 was identified as the main cause of the membrane pore blockage. • Ca2+ formed complexes with PVA-217 was developed as an efficient way to reduce membrane fouling. Papermaking industry discharges a huge amount of effluent and recycling of processed water with membrane technology has become predominate treatment protocol. In this study, poly(vinylidene fluoride) (PVDF) ultrafiltration membrane was employed to treat the effluent of secondary sedimentation tank from a paper mill. The results of 600 -hs continuous running showed that the PVDF membrane was seriously fouled with increased surface roughness during the filtrating process. Characterization of the fouled PVDF membrane revealed that pore blockage and cake deposition were the main fouling mechanism. The foulants in the pores were mainly oxygen-contained organics, and the foulants on the surface were mainly metal complexes and large particle. Wastewater analysis indicated the co-existence of PVA (1.0 mg/L) and Ca2+ (16.7 mg/L) in the secondary effluent. Pores blocking mechanism was caused by strong adheresion of PVA-217 and cake deposition mechanism was induced with macromolecular complexes of calcium ions bonding to PVA-217. The results obtained in this study demonstrated the fouling mechanism in the secondary effluent treatment. The understanding could help to find a feasible chemical method to clean the fouled polymeric membrane with washing agents as NaClO, NaOH and HCl in steps. [ABSTRACT FROM AUTHOR]

A range of energy fuels (ethanol, char, oil/wax and gas) was produced from fibre waste contaminated with plastic through the application of a fermentation-pyrolysis route. The fibre component was first converted to ethanol by simultaneous saccharification and fermentation (SSF), achieving an ethanol concentration of 39.8 g/L. The residue, enriched in lignin and plastics, was subjected to fast pyrolysis at temperatures between 350 and 550 °C. A wax product with a higher heating value (HHV) higher than 28 MJ/kg was obtained for temperatures higher than 450 °C, while values lower than 15 MJ/kg were observed for the oils produced from the untreated waste stream. Pyrolysis at 550 °C produced a wax with an HHV as high as 32.1 MJ/kg, where 51.8% of the energy content of the fermentation residue was transferred. The attractive energy contents of the pyrolysis products were enabled by oxygen removal from the feedstock during fermentation to ethanol. [ABSTRACT FROM AUTHOR]

• Two sub-period division strategies with MPCA are evaluated in SBR process. • Correlations between the different stages of SBR process are considered. • Four SBR parameters of field data from paper mill are utilized for fault diagnosis. • Sub-period division strategy based on similarity principle demonstrates best. Fault diagnosis of sequential batch reactor (SBR), a widely applied wastewater treatment technology in papermaking industry with huge discharge, has been a significant challenge due to the inherent multi-period characteristics of the process. In this paper, based on the conventional multi-way principal component analysis (MPCA) method (Scenario 0), two sub-period division strategies based on the processing phases of SBR process (Scenario 1) and the similarities of the loading matrices between the adjacent time slices (Scenario 2) are proposed for the detection of faults. Combined with Scenario 0, using the field data of blower current, level of SBR reactor, dissolved oxygen of wastewater and the blower valve opening in the SBR process of paper mill, two different fault diagnosis models with Scenarios 1 and 2 are developed and evaluated, respectively. The study results revealed that, both the calculated statistics of T2 and sum of prediction errors (SPE) of the fault diagnosis models with Scenarios 1 and 2 could detect the faults and identify the fault locations and sources. Compared to Scenario 0 which neglects the correlations between the different stages of SBR process, the fault diagnosis model by Scenario 2 demonstrated a superiority ability in fault identification in terms of the fault's time onset and fault's sources with adequate accuracy. The results enable the feasible and reliable implementation of the developed sub-MPCA diagnosis model with Scenario 2 in the actual SBR plants. [ABSTRACT FROM AUTHOR]

Paper and pulp mills generate substantial quantities of cellulose-rich sludge materials that are disposed in landfills at a large scale. For sustainability purposes, sludge materials can be bioprocessed to produce renewable fuels and useful chemicals. The enzymatic hydrolysis of cellulose is the process bottleneck that affects the conversion economics directly by using zero-cost raw materials. In order to study and optimize the process, the characteristics of the sludge raw materials should be first evaluated. In this work, sludge samples were obtained from paper mills located at different locations in Wisconsin and Minnesota. Part of the sludge samples was washed (de-ashed) with hydrochloric acid while the other part remained unwashed. The samples were subjected to multiple spectroscopic analyses techniques to evaluate the morphological properties of cellulose fibers and to estimate the total structural carbohydrate content. The results showed that the de-ashing process changed some fiber characteristics and cellulose crystallinity structure in all sludge samples. Sludge sample A (obtained from Kraft pulp and recycled paper mill region) showed a high percentage of fiber, with crystalline cellulose, compared to the other two sludge samples suggesting that sludge A is a valuable source to make value-added products. Aspen Plus mass and energy calculations performed in view of the 'zero' cost and the reliable supply of sludge raw materials producing 2 mol H 2 /mol glucose. Moreover, the results showed that extracting crystalline cellulose from these sludge samples is more profitable than crystalline cellulose made from the other lignocellulosic feedstocks. The results reported here showed that the utilization of these sludge materials would be an economically attractive and promising alternative for the production of hydrogen. Image 1 • A new method for paper mill sludge (PMS) characterization as renewable feedstock. • The deashing step has a major effect on the bioconversion of the PMS. • Studying the crystalline cellulose of the PMS. • A relation between the characterization and potential sugar yield was established. [ABSTRACT FROM AUTHOR]

• A generic mathematical model for the retrofit of water networks is developed. • The model is applicable to both direct reuse/recycling and regeneration schemes. • The model considers adding new pipes and modifying existing pipes. • Single- and multi-objective optimisation scenarios were presented with a case study. • Trade-offs among freshwater use, retrofit cost and modified pipes are explored. This work develops a generic mathematical model for process engineers and designers to retrofit existing water networks in process plants for water savings. The model is applicable to both direct reuse/recycling and regeneration schemes, with single- and multi-objective optimisation scenarios. The objectives of the model may include minimum water flowrates, minimum extent of retrofits and/or a reasonable payback period. A literature case study involving an existing water network in a pulp and paper mill is solved to elucidate the newly proposed model. The results of single-objective optimisation show maximum annual cost savings of $4,027,919 in the direct reuse/recycling scheme (with a 57.2% freshwater saving) and $4,420,975 in the regeneration scheme (with an 84.5% freshwater saving). For multi-objective optimisation, the use of the constraint method in the direct reuse/recycling scheme generates a range of Pareto optimal solutions for selection by the decision-maker. It was found that 88.1% of the freshwater saving can be achieved with 44.2% of the piping retrofit cost. Although the compromise solution obtained using fuzzy optimisation in the regeneration scheme achieves only 66.6% of the freshwater saving with 86% of the total retrofit cost, the number of new and modified connections is reduced by more than half. [ABSTRACT FROM AUTHOR]

The conventional biological treatment of pulp and paper mill wastewater may not be enough to satisfy the discharge limits, more effective processes such as advanced oxidation technologies may be used as advanced treatments for the removal of color and refractory contaminants. In this study, biologically treated effluent from pulp and paper mill (BTEPM) has been examined by iron-carbon micro-electrolysis coupled with H2O2 (ICME-H2O2). Under the optimal treatment conditions (Fe/C = 1:2.5, pH = 2.5, 100 min reaction, 9 mmol/L H2O2 added in three aliquots), the chemical oxygen demand (COD) removal efficiency attained 81% which is much more efficient than ICME without H2O2 under its optimal experimental conditions (42%). In addition, the initial biodegradability of BTEPM, as shown by BOD5/COD ratio, can be enhanced after treatment. The morphology and content of iron and the evolution of H2O2 content in the system under the optimal operating parameters were studied. [ABSTRACT FROM AUTHOR]

Currently, recycling and re-use of materials is extremely important due to the diminishing of natural resources. The objective of the European Union’s circular economy strategy is to increase recycling and the use of industrial waste materials and side streams as secondary raw materials. In this study, a chemical precipitation method to simultaneously remove ammonium nitrogen and phosphate from the liquid phase of anaerobic digestate using calcined paper mill sludge was studied. Papermill sludge is a waste material that forms in the paper-making process. In addition, commercial calcium oxide (CaO) was used as a reference precipitant. The suitability of the formed precipitate’s composition for recycled fertilizer use was also considered. The study results indicated that calcined paper mill sludge was as effective precipitant as commercial CaO in the removal of ammonium nitrogen and phosphate from the synthetic wastewater. In addition, the results indicated that calcined paper mill sludge removed efficiently phosphate from the liquid phase of anaerobic digestate, which led to the formation of hydroxyapatite, Ca5(PO4 )3 (OH). In this research we have shown, that calcined paper mill sludge can be used to produce recycled, slow-release, solid fertilizer. Another possible reaction, such as adsorption was also considered. [ABSTRACT FROM AUTHOR]

A new esterase gene est906 was identified from paper mill wastewater sediments via a function-based metagenomic approach. The gene encoded a protein of 331 amino acids, that shared 86% homology with known esterases. Based on the results of multiple sequence alignment and phylogenetic analysis, it was confirmed that Est906 contained a characteristic hexapeptide motif (G-F-S-M-G-G), which classified it as a lipolytic enzyme family V protein. Est906 displayed the highest hydrolysis activity to ρ-nitrophenyl caproate (C6), and its optimal temperature and pH were 54 °C and 9.5, respectively. Additionally, this enzyme had good stability under strong alkaline conditions (pH 10.0–11.0) in addition to moderate heat resistance and good tolerance against several metal ions and organic solvents. Furthermore, a specific nucleic acid aptamer (Apt1) bound to Est906 was obtained after five rounds of magnetic bead SELEX screening. Apt1 displayed high specific recognition and capture ability to Est906. In conclusion, this study not only identified a new esterase of family V with potential industrial application by metagenomic technology but also provided a new method to purify recombinant esterases via nucleic acid aptamers, which will facilitate the isolation and purification of target proteins in the future. [ABSTRACT FROM AUTHOR]

• Mixed microbial culture (MMC) selected with acidified pulp and paper waste. • The MMC adapted to the imposed conditions, demonstrating its robustness. • The MMC showed a stable polyhydroxyalkanoates (PHA) accumulation capacity. • New generation sequencing analysis showed an increase in PHA producers in the SBR. • Acidovorax and Comamonas were the dominant genera. Pulp and paper factories produce several residues that can be explored and valorized through polyhydroxyalkanoate (PHA) production via a three-step process. The objective of this work was focused on the selection step. Acidified hardwood spent sulfite liquor (HSSL), a fermented waste stream from a pulp and paper factory, was used to select a mixed microbial culture (MMC) in a sequencing batch reactor (SBR) operated for 156 days under different operational conditions. The MMC adapted to the imposed conditions, revealing its robustness whenever the operational parameters were changed. Feast-to-Famine ratio was kept below or equal to 0.2, with constant production of a copolymer of P(3HB- co -3 HV), and with storage contents values over 30 %. Changes in the operational conditions, namely cycle length, and organic load rate (OLR), successfully led to the selection of an MMC with a stable accumulation capacity and an increased biomass concentration. Next Generation Sequencing analysis was performed on samples collected during the SBR operational period. The analysis of the microbial composition of the MMC showed a rise in PHA-accumulating bacteria over time. Acidovorax and Comamonas species were found mainly to drive the PHA storage process during the first two periods of operation. After an increase in the OLR, in the last period, a shift towards Comamonas dominance occurred, suggesting a higher tolerance to the inhibitory compounds of the HSSL for this genus. [ABSTRACT FROM AUTHOR]

• Paper mill sludge was utilized for β-carotene production by Planococcus sp. TRC1. • Antibiotic and antioxidant potential of the nontoxic pigment was concluded. • Economic analysis revealed effective reduction in production cost. • Dual benefits were achieved through ligninolysis of the solid waste. • Crystalline cellulose rich biomass as value added product was recovered. Cost effective bioprocessing of nutraceuticals in present global scenario is a matter of concern. This study explored Paper mill sludge (PMS) and sugarcane bagasse (SCB) as inexpensive substrate for Planococcus sp. TRC1 mediated valuable β-carotene production and residual treated biomass as value added crystalline cellulose source simultaneously. Both biomass supported significant bacterial growth reaching highest yield 38.54 ± 1.4 mg/g on PMS (36 h) and 47.13 ± 1.9 mg/g (48 h) on SCB in solid state fermentation. Luedeking-Piret model revealed growth associated production with α and much lower β values of 5.18 and 0.24 for PMS and 4.5 and 0.165 for SCB. Cost analysis exhibited decrementation of pigment cost/mg by 84 % compared to synthetic media. Optimum production conditions were 30 °C temperature, pH 7, 10 % inoculum and initial moisture content 80 % (PMS) and 85 % (SCB). TLC (R f = 0.9), HPLC (RT = 7.646) and lambda max (465 nm) confirmed pigment's β-carotene nature with significant antioxidant and antimicrobial activity. It showed stability at varied temperature, pH and light conditions along with negligible phytotoxicity on Vigna radiata. Planococcus sp. TRC1 delignified PMS (41 %) and SCB (38 %) and FT-IR, FESEM and XRD suggested crystalline nature of residual cellulose rich fraction shedding light on a biorefinery approach for valorization of industrial solid wastes. [ABSTRACT FROM AUTHOR]

This study investigates the impact of incorporating lime mud (LM) as a filler material to develop sustainable, cementless ultra-high performance concrete (UHPC) by replacing silica powder (SP) and silica sand (SS) at varying percentages. Flowability analysis reveals that LM, with its distinctive particle size, influences flow characteristics differently at different replacement levels. Compressive strength was improved by 5.4% with 30% SP replacement, showcasing the role of LM in nucleation, as well as its particle size advantage. The heat of hydration analysis indicates that LM likely influences the early curing stages, enhancing reactivity and nucleation. TGA analysis also confirms that LM plays a role in hydration reaction, influencing weight loss and hydration peaks. The mercury intrusion porosimeter results show the impact of LM on pore distribution, with 30% for SP and 50% for SS replacements, favoring denser matrices. Life cycle assessment (LCA) demonstrates reduced CO 2 emissions and favorable environmental performance, highlighting the sustainability potential of LM replacements. Overall, the incorporation of LM in UHPC shows promise in terms of enhancing its mechanical properties and environmental sustainability. [Display omitted] • Lime mud (LM) in UHPC boosts material strength, leading to denser, more effective concrete. • LM enhances hydration, flowability, and refines pore structure. • High LM ratios in UHPC increase sustainability and reduce CO 2 emissions. • LM's use in UHPC significantly advances its mechanical properties and eco-friendliness. [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]

[Display omitted] • Paper mill sludge ash (pm SA) was used as catalysts to activate PMS. • Aerobic calcination was conducive to the exposure/formation of octahedral FeIII. • The O O bond fracture was the root pathway for FeIV O production. • The release of solid calcium in pm SA could inhibit the active decay of FeIV O. • The pm SA could effectively degrade similar pollutants in near-neutral water. The excellent performance of high-valent iron-oxo species (FeIV O) in the degradation of pollutants by activating peroxymonosulfate (PMS) had attracted much attention. However, the generation and reaction mechanisms were still unclear. In this study, iron-rich paper mill sludge was used as a raw material for the first time to prepare iron-based catalysts with abundant octahedral FeIII sites (Fe oct III). The results showed that the highest content of Fe oct III was found in the paper mill sludge ash obtained by aerobic calcination at 800 °C (pm SA800), and the pm SA800 could exhibit excellent catalytic activity (0.4785 min−1) and stability during the oxytetracycline (OTC) degradation process. The characterization and density functional theory (DFT) calculations further indicated that the Fe oct III was the dominant active site for FeIV O production. PMS tended to be adsorbed on two adjacent Fe oct III sites to form a [Fe oct III-OSO 2 OO(H)-Fe oct III] complex with a two-site adsorption configuration. Subsequently, the O O and O H bonds in [Fe oct III-OSO 2 OO(H)-Fe oct III] broken by absorbing energy, generating FeIV O. It's worth noting that the Ca species of pm SA800 effectively stabilized the pH of the reaction solution, which ensured the stable and continuous production of FeIV O. This work provides a new idea and insight for preparing catalysts that could produce FeIV O active species. [ABSTRACT FROM AUTHOR]

[Display omitted] • Green utilization strategy of sludge with cost-effectiveness and availability. • In situ Ca-doped CDs prepared from paper mill sludge for solar-thermal conversion. • Ultra-high solar-thermal conversion efficiency up to 137.58% was achieved. • Achieved highly efficient (2.94 kg m-2h−1) and recyclable (20-cycles) evaporation. • Exact role of Ca-doping for solar-thermal conversion enhancement was revealed. Solar interface water evaporator (SIWE) based on waste-derived carbon dots (CDs) are highly promising for large-scale production applications in the future, due to their low-cost, eco-friendly, and tunable structure and properties. However, there are still obstacles, including limited performance, blind selection of waste materials, and unknown underlying mechanisms between waste properties and the physicochemical properties of derived CDs. In this study, a novel CDs-based wooden SIWE derived from paper mill sludge (PMS) was constructed (called ESCDs-wood). Under 1 sun, ESCDs rapidly heated up from 15.6 °C to 53.5 °C and reached stability within 10 mins. The solar-thermal conversion efficiency of ESCDs was as high as 137.58 %, and the ESCDs-wood achieved a high evaporation rate of 2.94 kg m-2h−1. Moreover, the ESCDs-wood cost about $9 to complete 1 m2 evaporation. Meanwhile, the ESCDs-wood exhibited long-term stability, after 20 cycles, its solar-thermal conversion efficiency and water evaporation rate remained at 84.21 % and 85.03 % of the initial test, respectively. Moreover, the Ca-doping was found to be a key factor in effectively enhancing the solar-thermal conversion and the thermal stability of ESCDs, and the exact role of Ca-doping on the solar-thermal conversion performance enhancement of CDs was validated and revealed. Therefore, this study not only constructed a cost-effectiveness, high performance, sustainability, chemical-free, and eco-friendly SIWE, but also innovatively proposed the functionalization mechanism of Ca-doping for CDs and thus provided a new sight for the targeted regulation and design of CDs. [ABSTRACT FROM AUTHOR]

Biohydrogen and biomethane production via two stage sequencing system from paper mill effluent (PME) was evaluated to enhance its COD reduction. Heat-shock pretreatment of anaerobic sludge at 90 °C for 15 min was chosen to obtain a mixed microbial inoculum for dark fermentative hydrogen production. The effect of initial pH (5, 6 and 7) on the efficiency of hydrogen fermentation at different concentrations of substrate (3, 5 and 7 g-COD/L) was investigated, which the maximum hydrogen yield was obtained at initial pH 5. After that, the effects of substrate concentration (3, 5, 7, 10 and 15 g-COD/L) and fermentation temperature (37 and 55 °C) were investigated on the hydrogen production yield. The efficiency of dark hydrogen fermentation for all substrate concentrations was higher at 55 °C. The hydrogen production was enhanced as substrate concentration increased up to 5 g-COD/L, but then it was reduced, and the optimum hydrogen yield of 38.8 mL H 2 /g-COD initial was obtained at substrate concentration of 5 g-COD/L at 55 °C. The highest hydrogen (35.1 mL H 2 /g-COD initial) was obtained at 5 g-COD/L and 55 °C and the highest methane (553.8 mL CH 4 /g-COD initial) was obtained at 3 g-COD/L and 37 °C. Maximum COD reduction of 88.1% was obtained in two-stage sequencing dark fermentation/anaerobic digestion system at 3 g-COD/L and 37 °C. • BioH 2 and bioCH 4 were generated in expend of COD reduction from PME. • Effects of initial pH, COD loading and temperature were studied. • Primary step dark fermentation showed higher hydrogen yields at 55 °C. • Max COD reduction 88.1% was obtained in 2-stage sequencing system (3 g-COD/L, 37 °C). • 38.8 mL H 2 /g-COD initial at 55 °C and 553.8 mL CH 4 /g-COD initial at 37 °C were obtained. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the beneficial reuse of paper mill sludge as landfill cover and bottom liner material in municipal solid waste landfills. For this purpose, two-dimensional finite element analyses of a typical landfill geometry were carried out using PLAXIS finite element program. The results of the analyses were evaluated in terms of displacement and factor of safety (FS) values, and compared with those of the compacted clay. The results of this study showed that, vertical and lateral displacements of the landfill slightly increased while the FS of the landfill slopes decreased with increasing surface loading. However, for all the cases studied, lower vertical and lateral displacements and higher FS values were obtained for the landfills with paper mill sludge as the cover and bottom liner material in comparison to those of the compacted clay. Besides, for all the cases studied, FS values greater than 1.5 were obtained, indicating that the landfill slopes were stable under the proposed loadings and landfill cover and bottom liner materials. Based on these results, it can be stated that the paper mill sludge examined in this paper has geotechnical properties that are desirable for a landfill cover and bottom liner material for use as a substitute of compacted clay in municipal solid waste landfills. [ABSTRACT FROM AUTHOR]

Developing efficient and cheap electrocatalysts as substitutes for commercial Pt/C in the oxygen reduction reaction(ORR)is extremely necessary. Herein, paper mill sludge (PMS) was utilized to produce iron, nitrogen and sulfur co-doped carbon nanotube/nanoporous carbon nanocomposite (PMS-CNT/C) by pyrolysis. PMS-CNT/C-b, one of as-prepared PMS-CNT/C exhibited excellent oxygen reduction reaction activity with an onset potential of 0.99 V vs. RHE and half-wave potential of 0.77 V vs. RHE, which was similar to the commercial Pt/C catalyst (onset potential of 0.99 V vs. RHE and half-wave potential of 0.76 V vs. RHE). It had longer-term stability and higher methanol tolerance in alkaline medium than Pt/C. Moreover, the new catalyst also exhibited excellent catalytic performance in neutral solution. The energy output of microbial fuel cells loaded with PMS-CNT/C-b catalyst was also higher than that of commercial Pt/C under neutral condition. The excellent ORR performance of PMS-CNT/C-b was due to the carbon nanotube/nanoporous structure and the synergistic effect of abundant N groups, iron nitrides and thiophene-S. The formation of CNTs in the carbon nanotube/nanoporous carbon nanocomposite was mainly attributed to melamine, which was added into PMS and was at first just considered as a nitrogen source to develop N-doped PMS-based catalysis in this work. The synthesis of paper mill sludge-based carbon nanotube/nanoporous nanocomposite and its excellent ORR activity will make the new catalyst a promising cathodic electrocatalyst alternative for fuel cells. • Paper mill sludge (PMS) was utilized to fabricate Fe, N and S co-doped carbon materials. • Melamine was directly added into PMS to assist the formation of CNTs. • The PMS-based nanocomposites exhibited excellent catalytic activity for ORR. • A green and efficient strategy was developed for the reuse of PMS. [ABSTRACT FROM AUTHOR]

• Preparation of foams from paper sludge cellulose nanofibres and poly-vinyl alcohol. • Structure of the sludge CNF/PVA foams are competitive with commercial EPS foams. • Uni-directional freezing method enhances the foam structural properties. • The water solubility of CNF/PVA foam is an advantage for single use packaging. Porous foams from cellulose nanofibres (CNF) and poly-vinyl alcohol CNF/PVA were prepared by uni-directional freezing to create a homogeneous pore structure. The CNF was derived from paper mills sludge (PMS), a by-product of paper manufacturing waste-water treatment. Sodium tetraborate decahydrate (borax) was used as a crosslinking agent. The density of the CNF/PVA foams were 0.03 g cm−3 with a compressive strength of 116 kPa at 20% strain. The foams were competitive to commercial expanded polystyrene (EPS) foam. [ABSTRACT FROM AUTHOR]

This paper shows how chemical sludge (CS) generated during wastewater treatment at a paperboard mill can be quickly dried at low-temperature and employed in bark-fired boilers to reduce slagging and corrosion problems. By using a cyclone-dryer operated at an inlet-air velocity of 110 m/s and a temperature of 90 °C, the dry-matter content of CS was increased from approximately 19 to 82%. The residence time of CS inside the cyclone was approximately 2 s when using the inlet-air velocity mentioned above. Disaggregation of the feedstock caused by collisions with the cyclone wall and between particles played a crucial role in enhancing the efficiency of heat and mass transfer. Three co-pelletized mixtures of Scots pine bark (SPB) and dried-CS were combusted in a 40 kW fixed-bed burner. Flue gas analysis was performed with a gas analyser. Coarse and fine ash were analysed by SEM-EDS and XRD. NO x and SO 2 emissions increased with increasing amount of CS in the mixtures. Mono-combustion of SPB resulted in a large quantity of slag (i.e., molten ash) with a high degree of sintering (i.e., hardness of the slag), and ash deposits formed on heat transfer surfaces were rich in K 2 SO 4 and KCl. Mixtures of SPB and CS were less prone to slagging, and the amount of alkali chloride in the deposits was reduced in favour of alkali sulphate formation. Unlabelled Image • Chemical sludge was dried in a cyclone dryer operated at inlet-air temperatures of ~60–90 °C and velocities of ~60–110 m/s • The dry matter content of the sludge increased from 19 to 82% when the dryer was operated at 90 °C and ~110 m/s • Co-pelletized mixtures of Scots pine bark and dried chemical sludge were combusted in a 40 kW fixed-bed burner • NO x and SO 2 emissions increased with increasing amount of chemical sludge in the mixtures • All mixtures were less prone to slagging, and KCl in ash-deposits was reduced in favour of K 3 Na(SO 4) 2 formation [ABSTRACT FROM AUTHOR]

Adding biochar to paper mill biosolids (PB) amendments may affect PB mineralization rate and nitrogen (N) availability. The objective of this 224-day incubation study was to evaluate the effect of amending two PB types varying in carbon (C)/N ratio (PB1, C/N = 24; and PB2, C/N = 13) with three rates (0%, 2%, and 5%) of pine (Pinus strobus L.) biochar produced at 700 °C on the dynamics of total C, total N, mineral N, N mineralization rate, and microbial biomass C (MBC) and N (MBN) in two agricultural soils (Kamouraska clay and St-Antoine sandy-loam). Two reference treatments were also included, namely, mineral fertilization and unamended soil. Total soil C concentration remained stable over the incubation period, whereas a decrease in total soil N was observed in both soils. In comparison with the unamended soil, the application of PB significantly increased total N, NH 4 -N, NO 3 -N, net mineralized N, applied N mineralization rate, and MBC in both soils. In comparison with the application of PB alone, biochar addition increased total C and MBC but decreased NH 4 -N, NO 3 -N, net N mineralization, and applied N mineralization rate in both soils. The co-application of biochar and PB1 resulted in the sequestration of mineral N released, which was more pronounced in the Kamouraska clay soil. The co-application of biochar and PB2 resulted in moderate release of mineral N. This study showed that the co-application of biochar and PB can benefit agricultural soils by improving NO 3 -N retention in agroecosystems while increasing organic matter and promoting microbial biomass. [ABSTRACT FROM AUTHOR]

In this study, a series of polyaluminium chloride/papermaking sludge-based organic polymer (PAC-PSBF) composites with different PAC basicity and PAC/PSBF mass ratios were prepared from papermaking sludge. The basic properties of the aforementioned composites were characterized, and their flocculation efficiencies were studied in the disperse yellow (DY) and reactive blue (RB) dye removals. The results of the flocculation experiments demonstrated that PAC-PSBF composites performed better than PAC regardless of the PAC basicity or PAC/PSBF mass ratios. The composites with low PAC basicity were effective in DY and RB dye removals. PAC-PSBF composites with the same PAC basicity but higher PAC/PSBF mass ratios exerted more satisfactory color removals and floc properties in both DY and RB dye removals. PAC-PSBF composites were more pH-independent than PAC, and the excellent flocculation efficiencies of the composites was achieved at pH 4.0 to 8.0 in DY/RB dye removals. In brief, desirable flocculation efficiencies of the PAC-PSBF composites were obtained when PAC and PSBF were appropriately combined together. Image 1 • A series of PAC-PSBF composites were prepared from paper mill sludge. • Composites with distinct PAC basicity and PAC/PSBF mass ratios were prepared. • PAC-PSBF composites exerted more excellent flocculation efficiencies than PAC. • PAC-PSBF composites were more pH-independent than PAC. • The performance of the composites in DY/RB dye removals was far different. [ABSTRACT FROM AUTHOR]

This paper evaluates the environmental impacts of different alternatives for handling of sludge from paper and pulp mills in Sweden, using Life Cycle Assessment (LCA). The common practice of incineration of biosludge with energy recovery followed by landfilling of ash (System A) was compared with the alternative of digesting sludge anaerobically to produce biogas using different digestate residue management options. The digestate produced from anaerobic digestion (AD) was assumed to be incinerated for heat energy recovery in System B or pyrolyzed for biochar production in System C to be mixed with forest soils. The impact categories considered in this work are climate change, non-renewable energy use, mineral extraction, aquatic ecotoxicity, carcinogens and non-carcinogens. The LCA results demonstrate that the two proposed systems significantly reduce the environmental impacts of biosludge management relative to incineration. An 85% reduction in the aquatic ecotoxicity impact is achieved in System C, due to the reduced mobility of heavy metals in biochar relative to ash. System C, on the whole, outperformed the other two, leading the authors to the recommendation that the use of pulp and paper mill biosludge in biogas-biochar production systems is preferable to merely recovering energy from it. • Anaerobic digestion (AD)-pyrolysis and AD-incineration were modelled as biosludge treatment technologies. • Immobilization of the heavy metals in biochar significantly reduced aquatic ecotoxicity. • The lowest carcinogens and non-carcinogens impacts were offered by the AD-pyrolysis system. • From an environmental point of view, biogas-biochar is preferable to merely energy recovery. [ABSTRACT FROM AUTHOR]

Laccase has the enormous potential to be implemented as the multitasking biocatalyst in whole process of paper making. The enzyme can utilize effectively for pulping, delignification of pulps as alone or in the combination with other bleaching enzymes. Laccase has been evaluated for the biografting of pulp fibers, decolorize and stabilize the effluent of the paper mills, biotransformation of high molecular weight (HMW) lignins to lower molecular weight (LMW) aromatic compounds. Further this enzyme has the huge possibilities to apply for deinking of old newsprint (ONP) and pitch removal from varieties of the different pulps. There is no doubt on versatility mode of action of laccases in paper industry, but still there is limited commercialization of this enzyme has been possible, because of laccases has the less redox potential (E0) and needs mediators for the oxidation of non phenolic substrates, production of enzyme is cost intensive at large scale. This review is providing the proper updated information on the state of the art of different applications of laccase in paper industry. It also confer the interpretation to the readers about the areas of extensively studied and the field where there is still much left to be done. [ABSTRACT FROM AUTHOR]

This study is focused on the investigation of seven treatment strategies and the percentage reduction on COD and colour was evaluated and total time required for different treatment strategies were calculated. The results revealed that the COD and colour removal of 97% and 92%, respectively, was attained at 180 min of treatment for the coupled SPF-biological process, 97% and 90% of COD and colour removal was attained at 195 min of treatment for the coupled SPC-biological process whereas 98% and 95% of COD and colour removal at 95 min of treatment for the coupling of combined SPF-PC-biological process confirming the efficiency of the coupled process with a relatively shorter reaction time compared with the other processes. The values of the first order kinetics for the combined SPF-PC-biological process were 0.03 min-1 which is eight times greater than the biological process and 1.4 and 1.87 times faster than the coupled SPF-biological and SPC-biological process, respectively. The economic analysis of various AOPs and the relative cost of AOP-biological processes were discussed and the coupling of combined SPF-PC-biological process was found to be a technically and economically effective in treatment of pulp and paper mill wastewater to meet the effluent discharge standard. [ABSTRACT FROM AUTHOR]

• Nanocellulose production from Recycled Paper Sludge (RPS). • Ozonation was applied to RPS as a pretreatment, followed by maleic acid hydrolysis. • Ozonation affected the RPS fibers, as analyzed by various methods. • NC production improved with higher ozone doses, up to 0.8% (w/w) maxima. • Maleic acid was recyclable, thus contributing to the "green-industry" concept. Nanocellulose (NC) have garnered much interest worldwide due to its physical and chemical properties. Nanocellulose is produced from biomass materials by bleaching pretreatment, followed by acid hydrolysis. This work demonstrated the production of NC from recycled paper sludge (RPS), a crystalline cellulose rich waste, by ozonation pretreatment, followed by maleic acid hydrolysis. Ozonation resulted in removal of lignin (as evident by TGA analysis), negative zeta potential of RPS and enhanced NC production, from 60 mg/L to over 80 mg/L after 60–120 min of ozone treatment. Maleic acid was successfully recovered, although longer ozonation times reduced the amount of acid available for recovery. These results demonstrate that ozonation can be used as an effective pretreatment for NC production. [ABSTRACT FROM AUTHOR]

• Amphoteric flocculant, MCC(pAA-co-pDMC) was synthesized in NaOH/urea homogeneous system. • The mechanism of synthesis process and the structure of the flocculant were proposed. • MCC(pAA-co-pDMC) showed high removal efficiency for high turbidity kaolin suspension. An amphoteric flocculant, MCC(pAA-co-pDMC) was synthesized through an environmental friendly process. Methacryloxyethyltrimethyl ammonium chloride (DMC) and acrylic acid (AA) were grafted onto the skeleton of microcrystalline cellulose (MCC) in NaOH/urea homogeneous system. Orthogonal tests were carried out to achieve the optimal conditions of the polymerization process. Influential factors, which included reaction temperature, reaction time, molar ratio between MCC, acrylic acid and DMC were investigated. The degree of substitution (DS) of AA and DMC were 0.52 and 1.01 under the optimal synthesis conditions. Turbidity removal efficiency of the product can reach 99.82% for kaolin suspension with the initial concentration of 5.0 g/dm3 under pH 7.0. Structural characterization of FT-IR, XPS and elemental analysis were carried out and further confirmed the successful of the polymerization. Influence factors including flocculant dosage, pH and flocculation time were discussed. In addition, two coagulation-flocculation procedures were carried out to dispose kaolin suspension, results found polyaluminum chloride (PAC) (or CaCl 2) and MCC(pAA-co-pDMC) have synergy effect in turbidity removal with a significant dosage decrease at high removal efficiency. MCC(pAA-co-pDMC) coupled with ozonation process was used to treat black-middle effluent from pulp and paper mill and exhibited effective result on decolorization and turbidity removal. [ABSTRACT FROM AUTHOR]

Highlights • Lime sludge utilization in concrete, mortars, fired bricks, ceramics and cement. • 10–30% cement replacement in concrete and mortars by lime sludge is optimum. • 25–30% replacement of fine aggregates by lime sludge is optimum. • Bricks and ceramic production with lime sludge conserves less energy. • Lime sludge eco clinker synthesizes with less carbon footprint and temperature. Abstract This review paper encompasses the inclusive approach of lime sludge valorization in construction materials. Research studies based on cement and aggregate replacement by lime sludge concludes that 10–30% lime sludge is gainfully utilized in sustainable concrete and mortar. Additional prospect for lime sludge application in construction material is the production of cement and ceramics. Significant use of lime sludge in combination with supplementary cementitious materials such as silica fume, nanosilica and fly ash is recommended for the production of cement components and ceramics. The recommendations are also suggested in accordance with the outcome of the study. [ABSTRACT FROM AUTHOR]

As a major obstacle to high performance milling, chatter will inevitably decrease tool life, material removal efficiency and workpiece surface quality. Active control based on actuators for chatter suppression has been developed for a long time. However, in traditional active control, the feedback signals are usually time domain vibration signals, which will mitigate both chatter frequencies and normal frequencies, including rotation frequency and its frequency multiplications. In fact, rotation frequency and its frequency multiplications belong to normal cutting phenomenon, which don't need to be suppressed. Therefore, in traditional control strategies, more energy is wasted due to normal frequencies, which cannot obtain the optimal performance and causes the saturation effect of actuators. In order to solve this problem, this paper realized milling chatter suppression based on the adaptive vibration reshaping, which can precisely modify and control the milling vibration frequencies in frequency domain. Hence, the required control forces provided by actuators will decrease a lot, which can optimize the actuator performance and alleviate the saturation effect. Simulation results show that the adaptive vibration reshaping can suppress chatter frequencies effectively without changing rotation frequency and its frequency multiplications, which satisfies the initial control requirement for optimization of actuator performance. Besides, the convergence analysis, the noise resistance performance analysis, the control delay analysis and the chatter frequencies identification errors analysis are also presented for better facilitation to milling chatter suppression. Finally, contrastive milling tests are implemented on a three-axis milling machine. Experimental results show the designed control algorithm can decrease chatter frequencies, while having a little influence on normal frequencies. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A full factorial design was applied to produce paper mill sludge-based materials. • Highly efficient activated carbons (ACs) were obtained, with S BET up to 1627 m2 g−1. • Produced ACs were tested for the removal of 3 pharmaceuticals from water. • A desirability function was applied to determine the optimal production conditions. • Comparison with commercial AC revealed better performance for the waste-based ACs. Abstract The wide occurrence of pharmaceuticals in aquatic environments urges the development of cost-effective solutions for their removal from water. In a circular economy context, primary paper mill sludge (PS) was used to produce activated carbon (AC) aiming the adsorptive removal of these contaminants. The use of low-cost precursors for the preparation of ACs capable of competing with commercial ACs continues to be a challenge. A full factorial design of four factors (pyrolysis temperature, residence time, precursor/activating agent ratio, and type of activating agent) at two levels was applied to the production of AC using PS as precursor. The responses analysed were the yield of production, percentage of adsorption for three pharmaceuticals (sulfamethoxazole, carbamazepine, and paroxetine), specific surface area (S BET), and total organic carbon (TOC). Statistical analysis was performed to evaluate influencing factors in the responses and to determine the most favourable production conditions. Four ACs presented very good responses, namely on the adsorption of the pharmaceuticals under study (average adsorption percentage around 78%, which is above that of commercial AC), and S BET between 1389 and 1627 m2 g−1. A desirability analysis pointed out 800 °C for 60 min and a precursor/KOH ratio of 1:1 (w/w) as the optimal production conditions. [ABSTRACT FROM AUTHOR]

The electrochemical oxidation of organics in paper mill wastewater belonging to Halfa industries (Tunisia) was performed by galvanostatic electrolyses using electro-Fenton (EF) process. The effect of several operating parameters, such as applied current density, electrodes material, air pressure and the presence of sodium chloride (NaCl) was evaluated. In particular, carbon felt (CF), modified carbon felt (MCF) and gas diffusion electrode (GDE) were used as cathode while Ti/IrO 2 -Ta 2 O 5 and Boron Doped Diamond (BDD) as anode. Total Organic Carbon (TOC) measure was chosen as reference parameter to assess the extent of the treatment. The experimental results show that, by adopting the optimal set of operative conditions, EF can allow a high removal of TOC. It was shown that better performances can be achieved increasing the complexity of the treatment, by using sufficiently long electrolysis time or BDD as anode, MCF or GDE as cathode or the addition of NaCl. • The electrochemical oxidation of organics in paper mill wastewater was performed by electro-Fenton (EF). • A high removal of TOC is achieved at suitable operating conditions. • The process is improved using modified carbon felt of gas diffusion cathodes. • High TOC removal are obtained at long time with cheap anodes. • Short time are sufficient using BDD anode. [ABSTRACT FROM AUTHOR]

This work aims to produce ceramic-metal composite (cermet) membrane supports based on kaolin and aluminum powders. Flat ceramic membrane supports were prepared from the mixtures of kaolin (K), feldspar (F), sand (S), and two types of aluminum: industrial aluminum waste (Ali) and commercial aluminum (Alc).The samples were obtained by uniaxial pressing with 58.5 MPa in cylindrical moulds and then sintered at 1,350°C for 2 h in order to obtain flat cermet membrane supports of 30 mm in diameter and 6 mm in thickness. Porosity, permeability, and mechanical properties of these supports were studied as functions of the amount of aluminum powder. These characterizations proved that the addition of 4 wt.% aluminum to a 50% kaolin, 25% feldspar, and 25% sand porcelain matrix has a beneficial effect on the membrane support properties. In particular, the presence of aluminum progressively increased water permeability, porosity, and mechanical strength. The cermet membrane support application in the treatment of wastewater from paper mills shows a significant decrease in turbidity, about 97% retention rate of chemical oxygen demand, and an almost total color removal. [ABSTRACT FROM AUTHOR]

Abstract A new bacterial lipolytic enzyme Est903 was obtained from paper mill sludge via metagenomic approach. Est903 displayed moderate similarities to two lipolytic enzymes from Rhodopirellula islandica and contained a distinctive pentapeptide motif (GFSAG) that differed from those of all known fourteen families of bacterial lipolytic enzymes. Est903 was regarded as from a new bacterial lipolytic enzyme family through multiple sequence alignment and phylogenetic analysis. The recombinant Est903 showed the highest activity for ρ-nitrophenol butyrate. The pH optimum and temperature optimum of the recombinant enzyme was 9.0 and 51 °C, respectively. Also, this enzyme displayed moderate thermostability, high activity under alkaline conditions, and good tolerance against several organic solvents. In addition, the compatibility test and washing performance analysis revealed that Est903 had good compatibility with commercial laundry detergent and high cleaning ability of oil stains. These good properties make Est903 a potential candidate in organic synthesis or detergent industry. [ABSTRACT FROM AUTHOR]

Traditional wood-based panels composed of wood and petroleum based adhesives is widely used in furniture manufacturing and construction industries. However, these adhesives are not biodegradable, inhibiting the recycling of artificial board. More seriously, the emission of carcinogenic formaldehyde will lead to severe pollution and environmental issues. This study presents a method for preparing self-bonding composites. Waste poplar powder is used as raw material in the biocomposite, in which exogenous lignin is added, and lignin is extracted from the waste of the paper industry - black liquor, which is beneficial to the environment and the recycling of resources. The resulting biocomposites are characterized by aldehyde-free, better strength, and water stability. The dimensional stability and mechanical strength, bending strength (84.40 MPa), and tensile strength (35.40 MPa) of the biocomposite are 2.0 and 1.6 times that of composites obtained by hot pressing without pretreatment and are 2.7 and 2.4 times that of medium density fiberboard (MDF), lignin plays an important role as an adhesive, which is the key to improving mechanical properties. Moreover, the biocomposite features higher water stability and fire resistance than the traditional wood fiberboard. In conclusion, the developed black liquor-wood biocomposites are potential alternatives used to replace the formaldehyde wood-based fiberboard. [Display omitted] • An aldehyde-free wood-based panel was prepared by a resource-saving method. • The flexural and tensile strengths are 84.40 MPa and 35.40 MPa. [ABSTRACT FROM AUTHOR]

[Display omitted] • Calcium peroxide mediated disperser disintegration is a novel approach. • Acidic-calcium peroxide mediated disperser method solubilizes organics efficiently. • Bacillus aryabhattai amasses 85% polyhydroxybutyrate using pretreated sample. • Pretreated settled sludge yields 167 mL/g chemical oxygen demand of biogas. The proposed research envisioned to improve the accessibility of organics and hydrolysis of paper mill waste activated sludge for polyhydroxybutyrate production and anaerobic digestion. In order to fill this research gap an exploration has been made by adding lower dosage of calcium peroxide at acidic pH for the removal of exopolymeric substances thereby improving the disintegration efficacy. The results indicate that the calcium peroxide dosage of 0.06 g/g SS at pH 5 was optimum for floc fragmentation. The influence of floc fragmented sludge on disintegration by disperser shows the solubilization and solid decrement of 18.8% and 12.4% at the specific energy input of 4729.24 kJ/kg total solid. The impact of pretreated supernatant on polyhydroxybutyrate accumulation shows the maximum polyhydroxybutyrate content of 85.03 % while utilizing 60% (v/v) of pretreated sludge supernatant as a carbon source at 42 h. Subsequently, the settled sludge was directed towards an anaerobic biodegradability assay and found about 167 mL/g of chemical oxygen demand of biogas generation, which is higher than the crude sample (52 mL/g of chemical oxygen demand). The higher solubilization in pretreated sample reveals the easier accessibility of substrate by the microorganisms, thereby enhances bioenergy and valued product generation. [ABSTRACT FROM AUTHOR]