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Brazil is currently focused on its energy matrix transition in favor of increasing of the share of renewable energy carriers for both enhanced energy security and mitigation of greenhouse gas emissions. In this context, the country`s pulp and paper industry whose different wastes teams are not generally exploited, could play a critical role. Accordingly, the main objective of this work is to develop a conceptual ‘systemic’ biorefinery framework integrating the treatment of pulp and paper mill wastewater using upflow anaerobic sludge blanket (UASB) reactor with energy recovery through biogas production and its conversion into heat and power in stationary engines and boilers, respectively. Based on the results obtained through the present case study, it was revealed that the adoption of UASB reactors by the paper mill industry could properly addresses the environmental concerns faced while could contribute to the national agenda favoring an increasing share of renewable energies in the country`s energy matrix. The financial analysis showed that the investment required for the implementation of UASB reactors within a biorefinery platform would be minor vs. the investment in the whole mill and would be returned in 6.4 yr with a high return on investment even when operated at half of operational capacity. Moreover, through the developed UASB reactor-based biorefinery, the Brazilian pulp and paper industry as a whole could avoid 1.06 ×105 CO2eq tons, effectively contributing to the decarbonization of the country`s economy.

This article is a case study outlining the successful implementation of a wood chip pretreatment and interstage screening project at an integrated pulp and paper mill in Longview, Washington, United States. The article will review the process changes inspired by a businesswide energy-efficiency initiative, with a focus on a thermomechanical pulp (TMP) mill and its performance improvements that resulted from the pretreatment and interstage screening initiatives. A discussion of the mill's alignment with the local utility service provider, regarding leveraging energy credits to help fund the project, will be reviewed.

Solid waste of paper mill hydrapulper reject (HR) has a relatively high plastic content, with around 45-49% composition of the total HR. About 99% of the plastic has the catagory of High Density Polyethylene (HDPE). HDPE is a type of Polyethylene (PE) plastic which has high recyclability and may be re formed at high temperature. This study tries to discribe the potential of producing particleboards derived from HR using a hot-press method. Molded HR was being hot-pressed at a presssure of 25 k gf /cm 2 for 5 – 15 minutes of residence time, with a variation of of the amount of HR from 150-500 gram, and variations in hot-press temperature of 150-180 °C. The resulting product is then analyzed for parameters of moisture content, density, water absorption, thickness swelling, and internal bond compared to SNI 03-2105-2006 and JIS A 5908-2003. The results showed that most of the samples were relatively accepted to the SNI. The best results are obtained at HR weight of 250 gram with 165 and 180°C pressing temperature, and pressing time more than 10 minutes. The addition of HDPE pellets shows an increment of density and decrement of moisture content of particleboard, while the addition of MA shows some decrements of moisture content and water absoption of particleboard.

Purpose The purpose of this paper is to analyze the wastewater discharge and a zero-wastewater-discharge (ZWD) reproduction plan is designed for a paper mill in Taiwan. Design/methodology/approach The proposed model of ZWD reproduction planning is established using the fuzzy comprehensive evaluation and Taguchi method to determine the overall wastewater recovery rate. Still the prior studies failed to address a systematic approach to optimize the waste water recovery rate. Findings The optimal solution for clean water is 500 tons, recovery electrodialysis reversal is 345 tons, the wastewater reuse performance is 1.3 and waste heat recycling performance is 0.8, the larger number is performed well. The results shows that the maximum overall waste water recovery rate is 97.8 percent. Originality/value A paper mill is strived for improving their sustainable development. In real situation, there is a need to address the qualitative information and qualitative data to carry out the optimal ZWD reproduction planning.

Pollutants emerging from the effluents of paper mills eventually destroy the environment of our ecosystem. To find a proper solution of it, a cost-effective and environmentally benign technique is proposed here to remediate contaminants present in the effluent of paper mill in a sequential steps using advanced oxidation processes including Fenton reaction (FO) (Fe(II)/H2O2), modified Fenton oxidation (MFO) (Fe(II)/Zn(II)/H2O2) and biological flocculation process. A comparison and compilation among these techniques were carried out on the basis of the percentage removal of chemical oxygen demand (COD) as well as the observed degradation pattern in gas chromatography–mass spectrometry. Results revealed that MFO could remove ≥ 90% of COD at ~ 90 min, whereas FO could eliminate ≥ 80% COD at ~ 120 min. Further, the bioflocculation technique was found to reduce the heavy metal contents such as Fe, Mn, Zn, Co, Cd and Pb by ≥ 60%. In the sequential treatment process, lignin, phenolic and colour contents were also found to be reduced by ~ 84% ~ 97% and ~ 96%, respectively. Again, the bioassay tests were performed to verify the toxicity reduction in the industrial effluent after the application of the sequential treatment process. This study demonstrates that the sequential treatment technique could be an effective alternative for the treatment of paper mill effluent.

Huge quantity of paper mill wastes are dumped at the outskirt of factory as unwanted materials. Vermicomposting is an eco-friendly technique for beneficial conversion of different biodegradable/organic wastes into useful organic manure utilizing earthworms. Solid wastes generated in paper mills contain appreciable quantity of organic matter. Attempt was made for bio-conversion of Emami paper mill wastes with different numbers of Eisenia fetida (5–30 earthworms/2 kg substrate) for studying its influence on vermi-conversing time and quality of prepared vermicompost. Vermicomposting was carried out in trays following heap method and quality of final product was determined following both chemical analysis and bioassay on wheat seedlings. Application of more earthworms up to 20 numbers per 2 kg substrate made bio-conversion quicker but further addition of earthworm, however, delayed the process as some earthworms came out of beds and died probably due to competition for food among earthworms inside beds. Ten earthworms per kg paper mill wastes–saw dust–cow dung mixture (1:0.5:0.5 weight wise) was found as optimum earthworm population for preparing quality vermicompost having more major and secondary plant nutrients. Bioassay of this manure on wheat seedlings also confirmed the analytical findings. It is confirmed that earthworm population in vermibed played vital role in faster decomposition of paper mill wastes and releasing of more nutrients, which ultimately helped in better growth of wheat seedlings. Successful demonstration of vermicomposting technique will encourage local farmers for beneficial utilization of paper mill wastes in their agriculture.

This study examined the responses of a population of brook stickleback (Culaea inconstans) exposed to pulp mill effluent at Jackfish Bay, Lake Superior, Canada, in May 2007 and May 2011. Brook stickleback were extirpated from the effluent-receiving site, presumably due to anoxia after this period. Females at the effluent-receiving site had significantly larger gonad sizes in 2007 and 2011. In 2011, effluent-exposed female gonadal development was significantly advanced when compared with reference sites; they were the second most mature when compared among three different reference sites. Analysis of 7-ethoxyresorufin-O-deethylase activity revealed that effluent-receiving site females had greater CYP1A induction in 2007 and significantly greater CYP1A induction in 2011. Effluent-receiving site males showed significantly reduced CYP1A induction in 2007 and significantly greater induction in 2011. Chemical evaluation of sediment from the receiving environment showed elevated levels of resin acids and the polycyclic aromatic hydrocarbon, retene. Higher condition factors and more mature gonads were consistent with higher winter and spring temperatures modified by effluent or by lake vs. stream environments. Overall, effects on effluent-exposed brook stickleback were not consistent with reported effects in white sucker exposed to the same effluent in previous studies. This article has been made Open Access thanks to the kind support of CAWQ/ACQE (https://www.cawq.ca).

Pulp and paper mill biosludge becomes sticky after being dried to a certain solids content. As biosludge becomes sticky, it agglomerates and adheres to the heat transfer surfaces of the dryer. This undesirable property can lower the dryer efficiency and cause the drying equipment to fail. A systematic study was conducted to examine the sticky behavior of biosludge. The stickiness was evaluated by measuring the adhesive force between a sludge cake and a stainless steel substrate, and the cohesive force between a sludge cake and a sludge substrate. The results show that: i) both adhesive and cohesive forces increase markedly as the solids content increases, reaching a maximum value at about 13% solids, and then decrease steadily at a higher solids content; ii) cohesive force is stronger than adhesive force, implying that biosludge tends to agglomerate rather than adhere to smooth equipment surfaces; and iii) mixing wood fines or fly ash from a biomass boiler reduces the stickiness of the mixture. These findings may help mills improve the thermal efficiency of biosludge dryers and to turn biosludge into a more attractive fuel for burning in biomass boilers.

The European Union’s circular economy strategy aims to increase the recycling and re-use of products and waste materials. According to the strategy, the use of industry waste materials and side flows is required to be more effective. In this research, a chemical precipitation method to simultaneously remove ammonium and phosphate from the reject water of anaerobic digestion plant using calcined paper mill sludge and fly ash as a precipitant, was tested. Paper mill sludge is a waste material formed in the paper-making process, and fly ash is another waste material formed in the power plant. Objective of this research was to test whether these industrial waste streams could be used as low cost precipitation chemicals for ammonium and phosphate removal from wastewaters and whether the precipitate could be suitable for fertilizer use. Results indicated that calcined paper mill sludge had high removal efficiency for both ammonium (97%) and phosphate (73%). Fly ash also had good removal efficiency for both ammonium nitrogen (74%) and phosphate (59%) at 20 ± 2 °C. The precipitates contained high concentrations of nitrogen and phosphate and could be used as a recycled fertilizer. Other possible mechanisms for the removal of phosphate and ammonium were considered.

This study comprises the production and characterization of biodiesel, synthesized from the microbial oil of oleaginous yeast Pichia kudriavzevii NCIM 3653 which was cultivated using paper mill slu...

A delignification pretreatment of raw materials for paper and pulp industry is important as traditional chemical degradation is hazardous to health and the environment. The aim of the present study was to identify potential laccase producing fungi with special attention on their feasibility for the degradation of lignin of Bambusa nutans. Among 155 fungal isolates from bamboo stacking area of a paper mill, Inonotus pachyphloeus JP-1, characterized by morphological and internal transcribed spacer sequence analysis was found to have best potential for it. Laccase enzyme activity of the isolate JP-1 was studied for 72–288 h, and the highest activity of 666.8 nkat/ml was recorded at 144 h using 1 mM of CuSO4 as an inducer. B. nutans samples pretreated with the isolate recorded higher lignin degradation (45.80%) with minimum loss of cellulose content (2.24%) after 30 days of treatment. Furthermore, scanning electron microscopy, X-ray diffractometery and fourier transform infrared spectra of untreated and treated samples confirmed the effect of pretreatment on the cellular structure of B. nutans. This is the first report on I. pachyphloeus as a potent lignin degrader which can be further exploited for the development of clean technologies for paper and pulp industries.

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.

The total concentration of polycyclic aromatic hydrocarbons (PAHs) and some polyarenes in fouling (macrophytes) was determined for the first time in the framework of the Roshydromet observation system in Lake Baikal in 2014–2017. The concentration was determined for the coastal shallow part of the lake in the area of the former Baikal Pulp and Paper Mill (BPPM) (currently, the municipal wastewater discharge of the town of Baikal’sk) as well as for the north of the lake in the impact area of the Baikal-Amur Mainline (BAM). In BAM the total concentration of polyarenes in fouling is 1.4 times higher than in the area of the former mill, and in the area of BPPM the content of carcinogenic polyarenes is 2.5 times higher than in the north of the lake. The obtained characteristics of the modern level of polyarenes and PAHs in the lake macrophytes can be used as ecological criteria for improving the environmental control during the integrated monitoring of the lake.

The distribution of sulfide sulfur in different parts of Lake Baikal in 2014 and 2015 is analyzed. The concentration of sulfide sulfur in the bottom sediments varied from 0.002 to 0.830 mg/g dry weight (the average value is 0.042 mg/g). Maximum concentration of sulfide sulfur in the lake sediments were typical of the northern region, where the Upper Angara and Kichera rivers flow into, and of some stations on the profile along the Selenga River mouth as well as of the stations located in the zone of underwater discharge of wastewater from the town of Baikalsk and from the Baikalsk Pipe and Paper Mill closed in 2013. This is associated with the active inflow of organic matter to the water column and sediments in such zones.

The paper drying process has the highest level of energy consumption in the pulp and paper production process. Analysis and optimization of the energy system during the paper drying process is critical for improving the energy efficiency of the entire paper mill. In the existing model for the paper drying process, the solution requires accurate boundary conditions such as the air temperature and humidity of the pocket area and the cylinder surface temperature, which are very difficult to obtain in the papermaking process. This can result in significant deviations between the model solution and the actual production process. This paper focuses on the single-tier dryer cylinder-based paper drying process that has been widely used with high-speed papermaking machines in recent years. A mathematical model is proposed based on real-time data. The verification via industrial production demonstrates that the proposed model is reliable for the paper drying process. Based on the simulation results, two optimization operations have been proposed. The energy consumption decreases from 1.51 t steam/t paper to 1.44 t steam/t paper, 4.6% of the steam and 1.26 × 106 RMB can be saved for a medium-scale paper mill with the annual production capacity of 105 t paper.

Sweden is one of the largest exporters of pulp and paper products in the world. It follows that huge quantities of sludge rich in carbonaceous organic material and containing heavy metals are generated. This paper carried out a comparative environmental analysis of three different technologies, which can be adopted to produce biochar and recover energy from the biosludge, using landfilling as the reference case. These three thermochemical biosludge management systems—using incineration, pyrolysis, and hydrothermal carbonization (HTC)—were modeled using life cycle assessment (LCA). Heat generated in the incineration process (System A) was considered to be for captive consumption within the kraft pulp mills. It was assumed that the biochars—pyrochar and hydrochar—produced from pyrolysis (System B) and HTC (System C), respectively, were added to the forest soils. The LCA results show that all the alternative systems considerably improve the environmental performance of biosludge management, relative to landfilling. For all systems, there are net reductions in greenhouse gas emissions (–0.89, –1.43, and –1.13 tonnes CO 2 -equivalent per tonne dry matter biosludge in Systems A, B, and C, respectively). System B resulted in the lowest potential eutrophication and terrestrial ecotoxicity impacts, whereas System C had the least acidification potential. The results of this analysis show that, from an environmental point of view, biochar soil amendment as an alternative method for handling pulp and paper mill biosludge is preferable to energy recovery. However, an optimal biochar system needs to factor in the social and economic contexts as well.

Waste generation is increasing in many industries. Therefore, effective measures are required to secure an environmentally sustainable and economically viable waste destination. Co-processing in clinker kilns at high temperatures and incorporation into cement matrices may stabilize many types of industrial waste. This paper presents the results of a study that characterized pulp and paper mill waste and their recycling in clinker production. Chemical characterization and estimation of the hazardous potential of lime mud, biomass ash, and wastewater treatment plant (WWTP) sludge were performed in accordance with brazilian standard (NBR) 10004:2004. Biomass ash and WWTP sludge were classified as non-hazardous (class II), while lime mud was classified as hazardous (pH > 12.5, class I). These wastes were mixed (69 wt % lime mud, 29 wt % biomass ash, and 2 wt % WWTP sludge), and the resulting mixture was processed at 1455 oC to generate ‘ Ecoclinker ’. The clinker was characterized, milled, and mixed with calcium sulphate for use as an ‘Ecocement’ . Mortars were obtained and cured for periods of seven and twenty-eight days. The hardened product exhibited a mechanical strength of ~20 MPa. The leaching and pH tests indicated that these parameters were within the permitted limits, confirming that this waste-based cement was non-hazardous.

Pulp and paper mill industry is already known as an extensive water user and hence produces large volume of wastewater. Phytoremediation has merits to offer due to its environmentally friendly, relatively low cost and easy maintenance. This work focused on the performance of a continuous pilot subsurface flow (SSF) system of constructed wetlands in removing chemical oxygen demand (COD) representing organic carbon, colour and suspended solids from recycled pulp and paper mill under 5-day hydraulic retention time (HRT) for 95 days. In this study, there were two tanks based on the SSF system; one tank planted with Malaysian native bulrush (Scirpus grossus) and another tank without plants acting as a control. It was found that the SSF system with S. grossus was much better compared to the SSF control. Throughout the 95-day exposure, the planted SSF system have achieved removals of 66.1, 55.8 and 87.2% for COD, colour and suspended solid (SS), respectively. However, the control SSF system without plants has lower performance for all the three parameters (62.4% COD, 44.4% colour and 84.8% SS), giving evidence that constructed wetlands is an efficient technology to phytoremediate COD, colour and SS from recycled pulp and paper effluent.

In the present study, the photodegradation of lignin was studied using TiO2/Polystyrene composite under UV-LED irradiation in a batch-recirculated photoreactor as a supplementary treatment for pulp and paper industries. TiO2/PS composite was synthesized by the solvent-casting method and was characterized by scanning electron microscopy (SEM) and EDX analysis. The 3-level, 3-factor Box-Behnken design was applied to study the effects of main operating parameters and optimization of process circumstances. Besides, COD reduction efficiency, toxicity assays, and reusability were also investigated. The predicted model had R2 and R2adj correlation coefficients of 0.97 and 0.99 respectively, which showed experimental results were very close to the predicted values. Furthermore, under the optimal conditions (reaction time = 72.5, volumetric flow rate = 230 mL/min and lignin = 51.8 mg/L) the lignin degradation efficiency was 93.98%. The maximum COD removal (89%) obtained by 250 mL/min volumetric flow rate and lignin concentration of 50 mg/L after 120 min reaction time. Bioassay using D. Magna exhibited that at the beginning of the process, the toxicity of solution increased but continuously decreasing after then to very low values achieved within 120 min of photodegradation. In addition, the reusability tests demonstrated that the TiO2/PS composite after 5 cycles has a good stability and photocatalytic activity.

Pulp and paper industry is one of the high priority sectors that generates large amount of solid (sludge) and liquid (paper mill effluent) wastes. Making use of this huge quantity of paper mill sludge (PMS) in an environment friendly manner is challenging and cost involving. Similarly the present wastewater treatment strategies based on physical and chemical methods encounter certain serious setbacks including secondary pollution generation with expensive mode of abatement processes. The present study aims at a “waste treats waste” strategy for the bioremediation of paper mill effluent in fluidized bed reactor (FBR) using another waste of the same industry, PMS as immobilizing matrix for Planococcus sp. TRC1, a wastewater bacterial isolate. This study simultaneously explores this isolate for the yellowish orange pigment it produces (2.3 ± 0.2 mg/gm of dry bacterial biomass) and characterizes it as a member of the pharmacologically important carotenoid pigment family via UV-Vis spectrophotometry, TLC, FT-IR and 13C NMR. The antioxidant potential of this pigment was studied by DPPH assay (IC50 = 33 ± 0.4 μg/ml) and H2O2 assay (IC50 = 147.4 ± 2.2 μg/ml). In FBR, the PMS immobilized bacteria showed removal of phenol, lignin, colour and COD from the effluent by 96%, 74%, 81% and 85% respectively after 60hr of treatment. The experimental data on immobilization fitted well with pseudo second-order (R2 = 0.955) and Freundlich adsorption isotherm (R2 = 0.996) models. The alterations in PMS before and after bacterial immobilization, as revealed by SEM and FT-IR, depicted the success of PMS as immobilization matrix. Phytotoxicity (90% seed germination) and mutagenicity studies confirmed that the treated effluent was substantially less toxic than its raw state. This study highlights a novel utilization possibility of PMS in an eco-friendly and economic way as immobilization matrix for Planococcus sp.TRC1 for paper pulp mill effluent treatment along with production of carotenoid pigment from this potential bacterial isolate as value added product.

The article analyses waste generation of pulp and paper industry in North-Western Russia. The environmental impact of waste storage facilities of the pulp and paper mill was assessed, the need for utilization of lignin sludge was justified. In North-Western Russia, 1.21 million hectares of disturbed areas are in need for reclamation; they are abandoned quarries and lands alienated for pipeline and road construction. The suitability of lignin sludge for preparation of artificial fertile soils for reclamation purposes is estimated. For this purpose, experiments were carried out to create an artificial mixture with different ratios of lignin sludge and soil, to detect the maldevelopment of several plant species grown on various compositions of lignin sludge and soils. It was revealed that lignin sludge as an organic additive to soils is not toxic to vegetation and living organisms, allowing improving fertility of artificial soils.

Paper mill sludge (PMS) is a paper industry waste but can be a potential feedstock for cellulosic sugar production. In this study, washing, autoclaving, and surfactants were investigated for PMS pr...

In this study, a waste pickling liquor from a steel mill, which is rich in iron and acid, was used as the main raw material to prepare a composite coagulant: polymeric ferric aluminum sulfate chloride (PFASC). The as-prepared PFASC was used, together with PAM, for the tertiary treatment of papermaking wastewater to decrease its COD and Chroma. The Results from FT-IR and XRD of PFASC, supported the conclusion that polymeric ferric aluminum hydroxide hydrates compounds/ complexes are formed in the synthesized PFASC. When applied to a waste water sample from a paper mill, PFASC, together PAM, leads to decreases in COD and Chroma by 65.3% and 71.2%, respectively (initial pH 7.5, 1 ml/L PFASC, 1.0 ppm PAM). The technology has been implemented at a paper mill, and the obtained results are consistent with those from the laboratory.

Internal Circulation reactor (IC reactor) is an anaerobic digestive system with the capability to treat high-load Chemical Oxygen Demand (COD) of industrial wastewater (e.g. brewery, potato starch, pulp and paper). IC reactor advantages include of the following: only small areas required, shock load resistance, produces more biogas and uses less energy compared to the Upflow Anaerobic Sludge Blanket (UASB) reactor. BIOPAQ@ICX is an upgrade to BIOPAQ@IC that has higher efficiency, lower volume, able to build from the current anaerobic reactor, and its trial has produced positive results in many different countries and with various types of wastewater. A case study of the wastewater treatment plant at Saigon Paper’s mills shows that the IC reactor COD removal rate is over 80% when the COD is not over 2300 mg/L; Volumetric Load Rate (VLR) is 6–14 kgCOD/m3.day and the removal rate is higher with a higher load and could reach 80% at 14 kgCOD/m3.day; granular sludges settle very well, and the three-phase separator is efficient of preventing sludge from washing out; pH, Total Suspended Solids (TSS), alkalinity, Volatile Fatty Acids (VFA), N-NH4+, P-PO4 3-, Ca, SO4 2- were also analysed and indicated that the IC reactor is operating well.

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. NOx and SO2 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 K2SO4 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.

Publications baring falsified and fabricated images appear frequently in the primary literature. Industrialized forms of image forgery as practiced by the so-called paper mills worsen the current situation even further. Good education and awareness within the scientific society are essential to create an environment in which honesty and trust are the prime values in experimental research. Here I focus on the detection of publication fraud and provide some examples and advice. Finally, my views on the future of fraud detection and prevention are given.

Waste-to-energy or value-added products have been increasingly considered in many pulp and paper mills (PPMs) worldwide. However, developing appropriate conversion technologies is a major challenge in transforming PPMs wastes into biofuels or value-added biomaterials. In the present study, a long-term (320 d) anaerobic digestion of primary sludge of a thermomechanical pulp mill (TMP) was carried out for the first time in a thermophilic anaerobic membrane bioreactor (ThAnMBR). Effect of organic loading rate (OLR) in the range of 2.5–6.8 kg-COD/m3 d and hydraulic retention times (HRT) of 3–8 d on the process performance was investigated. Under various OLRs, stable biogas productions were obtained, and the best results were achieved with lower OLR (2.5 kg-COD/m3 d) and higher HRT (8 d), at biogas yields of 189 L biogas/kg MLSS fed. However, it was found that biogas production and sludge biomass degradation decrease when the organic loading rate increases. The proportion of sludge reduction ranged from 28.9 to 46.7% depending on the applied OLRs. Despite varying OLRs, stable membrane performance was obtained, where the required membrane flux was easily maintained during the reactor operation. In this study, also the properties of digestate and membrane permeates were studied under different operating conditions, and they fluctuated to some extent with OLR. ThAnMBR is a promising new technology for pulp and paper mill primary sludge treatment.

Microbial dehydrogenase activity can help to determine the oxidizing capacity of activated sludge. Here we propose an innovative and automated express-method based on rapid determination of dehydrogenase activity. The measurement is based on the rate of methylene blue reduction by living microbial cells in suspension. A single analysis takes 10 min. The method was adapted for biofilms immobilized on the floating carriers of industrial bioreactors and the kinetics of biological oxidation by activated sludge and biofilms was compared. New parameters were proposed to characterize the biological oxidation under low oxygen levels. The obtained make it possible to quickly determine the dehydrogenase activity of activated sludge and biofilms and promptly monitor the effectiveness of industrial biological wastewater treatment.

Funding Information: kindly performed all chemical analysis. This study was part of the joint research programme NSPPulp funded by TEKES, the Finnish Funding Agency for Technology and Innovation (nowadays, Business Finland). Publisher Copyright: © 2021. All Rights Reserved. In this study, the physical and chemical properties of untreated, lime-stabilised and composted wastewater sludges from a Finnish pulp, board and paper mill integrate were compared in order to assess their fertiliser properties based on the requirement of the Finnish Fertilizer Product Decree. Furthermore, the extraction properties of heavy metals in the sludges were assessed by the three-stage sequential extraction procedure of the Community Bureau of Reference (BCR) and the solubility indices for heavy metals were calculated in order to evaluate the release potential of elements from the sample (sludge) matrix. The results of this study indicated that the total heavy metal (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) concentrations in all sludges were lower than the statutory Finnish limit values for fertiliser products. However, the untreated sludge required either lime-stabilisation or composting in order to fulfil the Finnish maximum concentrations of pathogens (coliforms and Escherichia coli) for fertiliser products.

The main technological processes of Segezha pulp and paper mill JSC are described, the hydrological regimes unfavorable for production are justified, and the standards for permissible discharges of pollutants through the dispersing water outlet to lake Vygozero are calculated.

The pulp and paper industry consumes a huge amount of water and releases more polluted and colored wastewater every year. Many conventional techniques are used in the treatment of paper industry wastewater. However, for color removal from paper mill effluent, there is no proven method so far, on an industrial scale. Due to high energy input and high cost, there is an urgent need to find out a new technique that must be sustainable, economical, and environment friendly. Various methods have been investigated on bench scale and pilot scale also but no proven method for color removal on an industrial scale. The paper provides an overview of the color removal techniques from different sources of pulp and paper mill wastewater discharged by various industries. The review described various components involved in various processes for color removal from paper mill waste water. The present works focus on processes like chemical, chemical/physical, biological, physicochemical, and electrochemical applied in color removal from paper mill wastewater. The present review gives key information on the effectiveness, use, betterment, and limitations of numerous methods of treatment targeted at color removal from paper mill wastewater using various techniques still under evolution.

In recent years, the use of microalgae as feedstock for many marketable products, such as animal/aqua feeds, bioplastics and fertilizers, has gained renewed interest due to their fast growth potential coupled with relatively high lipid, carbohydrate and nutrient content. An algal biorefinery at an industrial site has the potential to sustainably and profitably convert carbon dioxide emissions into microalgal biomass and concomitantly reduce nitrogen and phosphorus from wastewaters. Industrial wastewaters are a potential alternative to traditional media used for large-scale microalgal cultivation. Pulp and paper mills are major consumers of water resources and discharge a huge amount of water to nearby lakes or rivers. This study investigated whether pulp and paper mill waste water is suitable for microalgal cultivation with the aim of achieving significant biomass production. Six different process waters from one Canadian pulp and paper mill were tested with two freshwater green microalgae. All of these waters were unable to support growth of microalgae due to inadequate nutrient concentrations, colour, turbidity and possible toxicity issues. HIGHLIGHTS Two freshwater microalgae strains were screened for potential growth on pulp and paper effluents.; Pulp and paper wastewater effluents were unable to support growth of the microalgae.; Chemical residues from the pulping process, such as peroxide and tannin, may inhibit algal growth.

The article presents the research results of the oxidation of watered toxic waste from the pulp and paper industry (sludge-lignin, the empirical formula of organic matter CH1.51N0.05S0.03Cl0.01O0.54) in supercritical water-oxygen (SCW/O2) fluid. The experiments were carried out using a flow tube reactor at a pressure of 25 MPa, temperature gradient along its vertical axis (from top to bottom: 390–600 °C), sludge-lignin flow rate of 9.5–14.5 g/min, oxygen ratio OR = 0.73–2.52, using NaOH (1.6 wt%) as a catalyst. Employing gas chromatography – mass spectrometry, polychlorophenols were identified in the composition of sludge-lignin, in which 2,4,6-trichlorophenol was the main component. The total yield of extracted phenols and chlorophenols per sludge-lignin organic matter was 20.82 and 2.88 μg/g, respectively. It is revealed that the conversion rate of sludge-lignin in SCW/O2 fluid is limited by heterogeneous oxidation of the carbonized residue, and is determined by the O2 content in the reaction mixture. At OR ≥ 1.16, only CO2, CO, N2, and N2O were detected in the volatile oxidation products. An increase in OR from 0.73 to 2.52 leads to a decrease in the total content of phenols (from 45540.1 to 129.3 μg/dm3) and chlorophenols (from 51.4 to 2.2 μg/dm3) in the water collected at the reactor outlet. It is shown that 2,6-dichlorophenol and 2-chlorophenol are the most resistant to oxidation. From the analysis of the initial sludge-lignin and mineral residues, it follows that the bulk of the chlorine contained in its organic matter is converted into NaCl in the course of oxidation.

In the screening area of the paper mill has the high density impurities which are removed from the pulp and it is stored in the machine chest. The pulp in the machine chest is directly transferred to the head box without removing any medium density sand particles which affects the quality of the pulp. Only if the pulp entering the paper machine is clean and well-mixed with additives a good quality of paper will be produced. So in between the pulp tank and the pulp receiver a medium density cleaner is installed. The pulp in the machine chest is allowed to flow through the round hopper. Due to the circulatory motion and by centrifugal force the high density sand particles will settle in the bottom of the hopper. Due to the centripetal force the pulp is recovered from the hopper. The sand particles that settled in the bottom of the hopper are removed by the periodic opening and closing of the solenoid valves at regular interval of time. The medium density impurities are removed by creating hydro cyclone. These sequential operations are automated and controlled through PLC. So the overall plant efficiency is increased. Since the medium density impurities are removed this ensures the good quality paper production.