Treatment Of Pulp Mill Wastewater Research Articles

Optimizing the Integration of Anaerobic and Aerobic Reactors for Enhanced Treatment of Pulp and Paper Mill Wastewater

Optimizing the Integration of Anaerobic and Aerobic Reactors for Enhanced Treatment of Pulp and Paper Mill Wastewater

Effect of treating birch kraft pulp with peracetic acid before O2-delignification on the properties of pulp and consumption of ClO2 in D0ED1 bleaching

The influence of pre-treating Kappa number of 18.0 industrial birch kraft pulp with peracetic acid (Paa) before oxygen delignification (OD) was studied relative to the pulps’ level of delignification, yield, brightness, intrinsic viscosity (IV), FS-number, tear index (TI), and the consumption of chlorine dioxide (ClO2) in its subsequent Elemental Chlorine Free (ECF) bleaching. The study showed that such pretreatment is a way to extend the delignification of such pulp quite selectively in OD based on values of IV, FS-number, and TI, and to reduce significantly the consumption of ClO2 required to bleach this pulp to a brightness of 87%. This reduction depended on the amount of Paa used for pulp pretreatment. For example, when 0.33% and 0.66% as active oxygen (A.O.) of Paa were used, ClO2 consumption to bleach the pulp to 87% was lowered by 15.4% and 42.3%, respectively. As high as a 61.5% reduction in ClO2 consumption in its bleaching could be obtained using 0.66% as A.O. on pulp and change of time of OD. This result allows for a significant decrease in the chlorine passing to the filtrates from washing the pulp after the D0 and E stages to the pulp mill wastewater treatment plant.

Hybrid solar drying of sludge from kraft pulp mills

Abstract Sludge generated from kraft pulp mill wastewater treatment plants (WWTPs) is typically non-inert solid waste and is commonly disposed of in landfills. In this study, a novel approach for repurposing WWTP sludge from a kraft pulp mill in Brazil for energy generation was assessed. With the global cellulose market projected to reach $ 61 billion by 2033, there is a growing need for sustainable energy solutions and disposal of associated industrial byproducts. This study investigated the performance of a hybrid active solar dryer for reducing the moisture content of sludge to enhance the feasibility of sludge burning in a biomass boiler. Through rigorous experimentation and design of experiments (DOE) planning, optimal parameters for the hybrid dryer were determined, specifically, a volumetric airflow rate of 1.1 m/s and an entrance temperature of approximately 51 °C. This innovative approach not only addresses the environmental concerns associated with sludge disposal, but also contributes to the broader goal of advancing sustainable technologies in the midst of global energy challenges.

Microbial Community Organization during Anaerobic Pulp and Paper Mill Wastewater Treatment

Microbial Community Organization during Anaerobic Pulp and Paper Mill Wastewater Treatment

Optimization and PID Control of pH and Temperature in an Electrocoagulation Process

In this work, effects of temperature and pH in batch treatment of pulp and paper mill wastewater using electrocoagulation has been investigated. Conductivity, temperature, and pH are selected as controlled variables; supporting electrolyte, cooling water, acid and base flow rates are selected as manipulated variables, respectively. Real time experimental multi input-multi output (MIMO) control of conductivity, temperature, and pH under constant current conditions are achieved using MIMO Proportional Integral Derivative (PID) control algorithms coded in MATLAB™. A central composite design (CCD) has been applied to the system under controlled conditions and optimum pH and temperature values are obtained using response surface methodology (RSM). Both controlled and uncontrolled experiments are performed using optimum values and results are compared in terms of removal efficiencies of pollutants. Results show that 34.47% chemical oxygen demand (COD), 98.06% total suspended solids (TSS), 99.80% turbidity, 99.93% color, and 13.40% SO42- removal is achieved in 45 minutes of process operation under controlled conditions and COD, TSS, turbidity, color and SO42- removal are increased by 10.92, 2.97, 4.06, 2.89, 3.17 respectively in comparison with uncontrolled operation. The highest removal percentages are obtained under controlled operating conditions as 98.5% and 98.3% for turbidity and color, respectively, for 10 minutes operation. It is concluded that optimum process operating conditions for removal of turbidity and color of pulp and paper mill wastewater is obtained under constant 6.45 pH, 23.24 °C temperature, 1.78 mS/cm conductivity, and power consumption is reduced by 25.3% under controlled conditions.

Advancing cobalt ferrite-supported activated carbon from orange peels for real pulp and paper mill wastewater treatment

The utilization of agriculture waste-based adsorbents in the treatment of real industrial wastewater represents an unexplored frontier with significant potential. In this study, the cobalt ferrite-supported activated carbon derived from orange peels (CF40-AC) was used as a magnetic adsorbent for the treatment of real pulp and paper mill effluent (PPME). Detailed insights into the properties and functionalities of the CoFe2O4-AC adsorbent were obtained through an accurate characterization analysis that included X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), BET and pore size histogram techniques. Both pure activated carbon (AC) and CF40-AC displayed excellent textural properties with surface area (SBET) equal 2014 and 1345 m2.g−1, respectively. TEM and SEM images display that the magnetic ferrites were well dispersed on the surface of AC. Following the characterization process, the CoFe2O4-AC adsorbent was evaluated for its ability to remove several key pollutants from PPME, including chemical oxygen demand (COD), total dissolved solids (TDS) and turbidity. Moreover, various operational parameters, such as pH, adsorbent dosage, contact time, and stirring rate, were investigated to achieve optimal contaminants removal rates. Remarkably, the CoFe2O4-AC adsorbent demonstrated highly efficient removal rates, with 86.9%, 59,9% and 93.1% for COD, TDS and turbidity, respectively, under optimal conditions (pH 7, adsorbent dose 0.4 gm, contact time 60 min, and stirring rate 150 rpm). The CoFe2O4-AC composite material exhibits promising potential for multiple applications reached 5 cycles without a significant loss in its adsorption or functional properties over successive uses. These results favor the promising potential of CoFe2O4-AC as a sustainable and efficient solution for addressing wastewater treatment challenges in the pulp and paper industry, contributing to both environmental protection and resource conservation.

Porous ceramsite catalytic ozonation for the treatment of pulp and paper mill wastewater in a continuous-flow reactor

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, O3 flow rate and O3 dosage. The optimum experimental conditions were obtained (T = 25 ℃, feeding flow rate = 0.25 L/min, O3 flow rate = 0.5 L/min, O3 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.

Catalytic Ozonation for Pulp and Paper Mill Wastewater Treatment: COD Reduction and Organic Matter Degradation Mechanism

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

Ultrasound‐assisted photo‐Fenton process for treatment of pulp and paper mill wastewater and reduction of phytotoxicity

AbstractThe efficiency of classical Fenton (CF) and modified Fenton (MF) as well as photo‐Fenton processes in real wastewater treatment of pulp and paper (P&P) mill was investigated in this study. The chemical oxygen demand (COD) was chosen as the reference measurement for evaluating the treatment's efficiency. After determining the optimum parameters for each process, the effect of adding ultrasound (US) on improving treatment efficiency was examined. In addition, kinetic study and phytotoxicity analysis were conducted under optimum conditions for all processes. With pH 4, reaction time 50 min, 1.2 g/L Fe2+ and 8 g/L H2O2 dosages, the best removal efficiency (RE) of COD was determined to be 82.18% in CF process, and this rate rose to 90.1% when US was added. The best RE in MF process was 84.16% with the application of UV‐C, pH 4, reaction time 50 min, 1 g/L Fe0 and 8 g/L H2O2 doses, although it increased to 93.4% when US was applied. The greatest results in the seed germination test were achieved in US processes with 100% of germination percentage (GP) for spinach and tomato and 90% for cress. In the economic evaluation, when conducting the treatment without US, the estimated relative cost decreased in a 15 and 16%, for CF/UV‐C and CF processes respectively, whereas the CF process was 64% cheaper than the MF process in all applications. The US contributed to enhanced water treatment efficiency by having a significant synergistic impact on Fenton applications. Hence, the combination of photo‐Fenton and ultrasound to treat effluent from P&P mills proved to be an effective and promising technique.

The Ability of a Bacterial Strain to Remove a Phenolic Structure as an Approach to Pulp and Paper Mill Wastewater Treatment: Optimization by Experimental Design

High-colored wastewater generated during the cellulose bleaching process causes the inhibition of biological activity when released into the environment. This study aimed to evaluate the bacterium’s capacity, identified as RGM2262, to degrade a complex phenolic structure such as lignin, which is found in high concentrations in the effluents generated during the production of cellulose, raw material for the manufacture of paper. To determine the values of the experimental variables that allow for a greater degradation of organic matter, an experimental model was carried out through experimental design. Thus, the experimental matrix was obtained with the variables pH 7 (−1) to 9 (+1) and a treatment time of 1 day (−1) to 5 days (+1). The results show that, at pH 8 and pH 9, both treatments—with bacteria in bio-films and without bio-films—were efficient. On the second day of treatment, 100% of the color and the phenolic structure were removed, with a similar rate constant, and at the same time, 80% COD and 70% of TOC, respectively.

Developing the nitrogen handprint approach to quantify the positive impacts of industrial symbiosis on nitrogen cycles

Excessive nitrogen (N) uptake for nutrient use in food production and industry and increased N losses to the environment severely interfere with nutrient cycles and harm the environment and thus, closing N cycles through N recovery and recycling is required to improve N use efficiency. To quantify positive impacts enhancing N cycles, this study suggests a novel N handprint approach, which combines life cycle assessment based nutrient footprint and carbon handprint approaches. The N handprint comprises of a set of indicators providing a wide systemic view on changes in N cycles. The case study demonstrates that the N handprint is created when a recycled N nutrient product is used instead of a virgin N nutrient for the needs of a pulp and paper mill wastewater treatment. According to our results, the handprint equals a reduction of 454 kg of virgin N inputs, and 5.6 kg of total N inputs for daily treated wastewater. Additionally, global warming potential is 91%, and the eutrophication potential 48% lower for the recycled N nutrient than for the virgin N nutrient. These results can be used to promote the use of recycled N on similar occasions in order to improve nutrient use efficiency. • The nitrogen (N) handprint approach aims to highlight efficient nutrient use. • The approach is combining carbon handprint and nutrient footprint. • The approach is applied to N recycling in an industrial symbiosis. • N handprint enables to show positive environmental impacts of circular N solutions.

Batch Electrochemical Treatment of Raw Pulp and Paper Mill Wastewater Using Electrode Combinations

SS and Cu electrodes were used in the electrochemical coagulation to treat pulp and paper mill wastewater using 4SS and 3SS 1Cu electrodes by applying cell voltages 12 – 24 V. Optimal cell voltage 18V showed COD removal of 89.64% for 4SS electrode and 84.74% for 3SS 1Cu electrode with simultaneous color removal of 99% and 90%. Other control factors used for optimal operation are sludge volume index (SVI), filterability, etc. SVI values were <100 mL/g for 4SS electrodes. The filtration characteristics of the ECC-treated sludge were established to determine the specific cake resistance (α) and the resistance of the filter medium (Rm). Lower α and Rm values for 4SS and 3SS-1Cu electrodes were found at 60 min ET. Proximate and ultimate analyses showed that 4SS and 3SS-1Cu sludge could be used as additive as well as adsorbent material for treating low strength wastewater.

Removal of colour and lignin from paper mill wastewater using activated carbon from plastic mix waste

The study aimed at the use of char produced during pyrolysis of mix plastic waste. It further focused on producing activated carbon from char and also found its efficacy as efficient adsorbent for treatment of pulp and paper mill wastewater. The activated carbon was characterized in comparison with raw char for their physical, surface and adsorptive properties. Batch type adsorption experiments were carried out using 100 ml wastewater to observe the individual effectiveness using five different variables such as adsorbent dose (0.25–2.0 g), pH (6–10), time (5–24 h), agitation speed (100–200 rpm) and temperature (30–50 °C) by keeping other variables constant which helped to find out the effective range of all the variables. The competency was evaluated on the basis of colour and lignin content of pulp and paper industry wastewater. Once the effective range of different variables was identified, the statistical analysis was conducted to monitor the mutual impact on the reduction in colour and lignin contents in wastewater. From the statistical design applied, the best result was obtained at activated carbon dose (1.25 g), pH (8.0), contact time (7 h), agitation speed (184 rpm) and temperature (40 °C). The study resulted in reduction of 96.48% in colour and 94.25% in lignin at optimized condition in comparison with 87.37 and 80.44%, respectively, at unoptimized conditions. A potential increase in reduction of 9.0% in colour and 14.0% in lignin content was achieved after optimization through statistical design that confirmed its usefulness.

Electrocoagulation of kraft pulp bleaching filtrates to improve biotreatability

Bleached kraft pulp mills generate large volumes of effluents usually treated by biological processes that don´t remove recalcitrant organic constituents. The present study was undertaken to evaluate the potential of electrocoagulation of acid (AcF) and alkaline (AlF) kraft pulp bleaching filtrates with Al and Fe electrodes to improve their biotreatability. Response surface methodology was used to predict the effects of initial pH, current density, and electrolysis time on biodegradability (BOD/COD). Biodegradability increases of 1.7–2.1-fold were obtained using optimized experimental conditions for each electrode-filtrate combination: AcF-Al (pH 7.9, 128 A/m², 49 min), AcF-Fe (pH 4.6, 104 A/m², 40 min), AlF-Al (pH 3.8, 150 A/m², 52 min) and AlF-Fe (pH 6.3, 101 A/m², 42 min). Electrocoagulation with Al electrodes was more efficient in removing color, phenols and estrogenic activity, but required longer reaction time and higher current density, while treatment with Fe electrodes resulted in lower toxicity to Daphnia similis. Electrocoagulation of both filtrates before combining them for biological treatment led to 88 % dissolved organic carbon (DOC) removal in a five-day biodegradability test, compared to only 27 % DOC removal from combined raw filtrates. The potential to increase overall pulp mill wastewater treatment efficiency using electrocoagulation prior to biological treatment was demonstrated.

Modelling of a pulp mill wastewater treatment plant for improving its performance on phosphorus removal

The performance of a pulp mill wastewater treatment plant (WWTP) was assessed using the software BioWin aiming at providing alternatives for reducing even further the phosphorus (P) concentration in the treated effluent. The WWTP was designed without nutrient removal capacities, since pulp and paper wastewater is usually deficient in nutrients. However, the hard wood (Eucalyptus) which is processed in such plant has a higher P content compared to other types of woods, and part of that P ended up in the raw wastewater to be treated. The wastewater was characterized following the Dutch STOWA protocol. Once the model was calibrated, historical data from different periods of time was used to validate the model. The model was capable of describing the current plant operation, as well as its historical performance. Moreover, the model was used to evaluate different potential upgrading scenarios for the treatment plant aiming at increasing the plant performance on P removal. According to the model, the implementation of an anaerobic phase prior to the aerobic process showed to be a feasible scenario contributing to decrease the total phosphorus (TP) concentration in the treated effluent by approximately 58 %. In addition, applying chemical precipitation can further decrease the TP concentration below 0.1 mg/L. However, further research activities such as pilot-testing may be needed to validate the previous recommendations of applying enhance biological and chemical P removal at such pulp mill wastewater treatment plant.

Characterization of reversible and irreversible foulants in membrane bioreactor (MBR) for eucalyptus pulp and paper mill wastewater treatment using fluorescence regional integration

Abstract Membrane bioreactors (MBRs) are an alternative technology to achieve high quality effluent for water reuse for eucalyptus pulp and paper (P&P) industries, but membrane fouling is still a challenging factor that restricts its application. This study aims to investigate characteristics of reversible and irreversible fouling of the submerged polyvinylidene fluoride (PVDF) MBR for treating eucalyptus P&P wastewater. Six batches of MBR experiments with different mixed liquor suspended solids (MLSS) concentrations were performed. The membrane cleaning protocol included three-steps: backwashing with DI water and subsequently NaOH solution, and then soaking with NaOCl solution, for which achieved 54.6 ± 11 %, 76.6 ± 10 % and 97.8 ± 2 % of flux recovery, respectively. Formation of a cake layer comprised of organic substance and soluble microbial products (SMPs), mostly polysaccharides and proteins, was the main contributor to flux decline of the MBR. Concentration of proteins in the irreversible foulant was found to be positively correlated with degree of membrane fouling. Using fluorescence excitation-emission matrix (EEM) with fluorescence regional integration (FRI) analysis revealed that, during MBR treatment, protein-like substances in the permeate water significantly decreased, simultaneously with the increase in relative proportions of humic-like and fulvic-like substances. Further analysis on the irreversible foulants showed that protein-like substances, including tyrosine-like and tryptophan-like substances, were disproportionately more important to membrane fouling than humic-like substances relative to their respective concentration in raw P&P wastewater.

Advanced numerical kinetic model for predicting COD removal and optimisation of pulp and paper wastewater treatment by Fenton process

ABSTRACT In the present study, a kinetic model has been developed to predict the chemical oxygen demand (COD) removal efficiency of Fenton process for the treatment of pulp and paper mill (P&P) wastewater. In order to investigate the effects of main parameters including Fe(II) dosage, H2O2 dosage, and pH, 45 experiments have been carried out at three levels for each parameter, and thus COD removal efficiency has been obtained. The Fenton process was simulated by using 10main reactions, and the model was solved numerically according to a specific algorithm. All the pollutants in the P&P wastewater were assumed to be a pseudo-material, andapparent kinetic constant (k**)was calculated using a developed iterative method. The results of the numerical model indicated that the proposed model had a great potential to predict COD removal efficiency for P&P wastewater by Fenton in comparison to the first and second-order kinetic models. Accordingly, R-squared (R 2), Root Mean Square Error (RMSE), and Mean Relative Error (MRE) of the numerical kinetic model were 0.93, 4.296 × 10−7, and 0.035, respectively, implying remarkable accuracy of the numerical model. Furthermore, at the optimum point of Fenton process,which was pH: 3,[H2O2]:0.015 Molar, and [Fe(II)]: 0.015 Molar, the COD removal efficiency of P&P wastewater reached 78%. As the basis of the numerical model was established according to mechanisms of Fenton process, the results demonstrated the great performance of the advanced kinetic model in the estimation of the COD removal efficiency, the behaviour of effective parameters such as pH, H2O2, and Fe(II) along with their effects on k**, and Fe(III) accumulation during Fenton process.

Complete Genome Sequence of Rhodococcus ruber R1, a Novel Strain Showing a Broad Catabolic Potential toward Lignin-Derived Aromatics.

Rhodococcus ruber R1 was isolated from a pulp mill wastewater treatment plant because of its ability to use methoxylated aromatics as growth substrates. We report the 5.56-Mb genome sequence of strain R1, which can provide insights into the biodegradation of lignin-derived phenolic monomers and potentially support processes for lignocellulose conversion.

Tertiary treatment of pulp and paper mill wastewater by iron–carbon micro-electrolysis coupled with H2O2

Tertiary treatment of pulp and paper mill wastewater by iron–carbon micro-electrolysis coupled with H2O2

Resource recovery assessment at a pulp mill wastewater treatment plant in Uruguay

Using a mathematical model, a resource recovery assessment was carried out at a pulp mill activated sludge wastewater treatment plant (WWTP) located in Uruguay. Through the evaluation of different scenarios, the potential production of methane from secondary sludge, with its inherent energy savings, and the recovery of phosphorus (P) as struvite were estimated. Considering the current WWTP configuration with a sludge retention time (SRT) of 32 days, and according to the model, which is a simplification of reality, the assessment indicates that the implementation of an anaerobic digester (AD) to treat the excess sludge can lead to a methane production of approximately 1736 m3 CH4 d−1, being a promising alternative to increase the WWTP treatment performance. Furthermore, the model predictions suggest that by shortening the SRT from 32 to 5 days, the methane production could increase by up to 5568 m3 CH4 d−1. If the methane produced is used to generate electrical energy to operate the WWTP, energy savings of about 88% can be achieved. Regarding the potential recovery of P as struvite, the addition of a struvite reactor could be an efficient option to recover approximately 1611 mg L−1 of struvite (corresponding to a load of about 433 kg d−1). By optimizing the process performance, these findings highlight the potential recovery of resources in pulp mill WWTP, while complying with stringent effluent discharge standards. In addition, further research activities such as pilot-test or detailed laboratory studies may be needed to validate the previous recommendations for industrial scale application.