Treatment Of Paper Industry Wastewater Research Articles

Synthesis and characterization of novel β-CD-Xanthate and its application in the treatment of heavy metal containing wastewater and lignin enriched paper industry wastewater

ABSTRACT Three grades of β-cyclodextrin xanthates (β-CDXs) have been synthesized by the reaction of β-cyclodextrin (β-CD) with CS2 in alkaline medium (NaOH), through xanthation process. The synthesized β-CDXs has been characterized by UV-visible (UV-Vis) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, Proton Nuclear Magnetic Resonance (1HNMR) spectroscopy, Thermogravimetric (TG) analysis, Differential Scanning Calorimetry (DSC) analysis, scanning electron microscopy (SEM) analysis and point of zero charge (ΔpHPZC) analysis. Further, β-CDXs and raw β-CD has been used for the heavy metals removal (Cu2+ and Ni2+) and also used for the treatment of lignin enriched paper industry wastewater (LEPIW). The maximum % removal by β-CDX3 for Cu2+ ion at optimum dosage of 2 g/L, optimum pH of 6.5, temperature of 45°C, initial concentration of 1000 mg/L and at contact time of 80 min was 95.8%. For Ni2+ ion the maximum % removal by β-CDX3 at optimum dosage of 2.5 g/L, optimum pH of 5.8, initial concentration of 1000 mg/L, temperature of 55°C and contact time of 100 min was 94.1%. While LEPIW treatment efficacy of 86% has been observed with β-CDX3. The calculated data fitted well in Langmuir isotherm model confirming that the adsorption of Cu2+ & Ni2+ ions onto the β-CDXs adsorbent is monolayer. The rate of adsorption of heavy metals (Cu2+ and Ni2+) on the β-CDXs adsorbent has been controlled by Pseudo second order kinetic model indicating the chemisorption process. The optimal adsorption capacity of β-CDX3 has been found to be 534.75 mg/g for Cu2+ and 423.72 mg/g for Ni2+ ions, respectively.

Simultaneous production of polyhydroxybutyrate and biogas from paper mill sludge through sodium citrate-mediated disperser-induced phase separated pretreatment

Paper mill waste activated sludge is an excess sludge produced from the paper industry wastewater treatment plant. Because of the bulk nature, its disposal concerns both economic and environmental perspectives. However, it widely consists of organic components and is considered a major attraction for its valorization to produce bioenergy and valued products. During the bioenergy and valued product retrieval, the enzymatic hydrolysis got hampered due to the presence of exopolymeric substances and thus require proper pretreatment prior to the product recovery. The application of two different phases of pretreatment by removing the flocs in the first step and then followed by the cell disintegration by mechanical means helps in enhancing the organics efficiently in soluble phase. In this study, the upshot of sodium citrate mediated disperser disintegration on sludge from a paper mill was explored enhance enzymatic hydrolysis. Firstly, the floc deaggregation results at 0.05 g sodium citrate per g suspended solid with the maximum floc deaggregation degree of 89 %. Further, the consequence of disperser disintegration on the floc deaggregated sludge sample shows solid reduction and solubilization of 12.5 % and 17.5 %, respectively, higher than the disperser alone disintegration (9.57 % and 13.4 %). The anaerobic biodegradability assay shows the maximum biogas production of 174.3 mL/g of chemical oxygen demand while utilizing pretreated settled sludge as substrate. There was no accumulation of polyhydroxybutyrate using pretreated sludge supernatant. Thus, the phase-separated pretreatment by sodium citrate-induced disperser pretreatment is a suitable approach for enhancing hydrolysis during bioenergy recovery.

Synthesis and characterization of pectin-xanthate and their application in heavy metal and lignin enriched paper industry wastewater treatment

ABSTRACT Three grades of pectin xanthates (PX1, PX2, and PX3) have been prepared by the reaction of pectin with carbon disulfide (CS2) in an alkaline medium using NaOH, via the xanthation process. The percentage yield of prepared pectin xanthates has been found to be 87.06%, 90.38%, and 93.80% for PX1, PX2, and PX3, respectively. Prepared pectin xanthates and raw pectin were utilized for heavy metals (Cu(II) and Ni(II)) and lignin enriched paper industry wastewater (LEPIW) treatment. The removal percentage of pectin, PX1, P X2, and PX3 for Cu removal at optimum condition (adsorbent dose: 5.14 g/L, pH: 5 for Cu and 7 for Ni, optimum temperature: 50°C and time: 80 min for Cu(II) and 100 min for Ni(II)) has been found as 85%, 92.33%, 93.5%, and 94.66% and 76.66%, 89.44%, 91.66%, and 93.33%, respectively, for Ni removal. The LEPIW treatment efficacy for pectin, PX1, PX2, and PX3 has been found to be 54%, 77%, 83%, and 86% for the initial COD: 2000 mg/L, pH: 7, optimum temperature: 40°C in 105 min operation time. Adsorption isotherm studies suggest that Langmuir isotherm is most appropriate which indicates adsorption follows chemisorption. The adsorption capacities of PX1, PX2, and PX3 are found as 309.59, 352.11, and 380.22 mg/g for Cu(II) and 299.40, 315.45, and 328.94 mg/g and for Ni(II), respectively, which is very high in comparison with many other recent literature studies.

Enhanced biodegradation of toxic pollutants from paper industry wastewater using Pseudomonas sp. immobilized in composite biocarriers and its toxicity evaluation

The present study focused on the immobilization of Pseudomonas putida strain using polyvinyl alcohol mixed with sodium alginate (PVA-SA) and agar-agar (PVA-AA) for the treatment of paper industry wastewater. The bacterial culture immobilized in PVA-SA polymer efficiently removed BOD5, COD, TKN, and TOC, phenol, lignin and color was 69.6 %, 78.6 %, 81.7 %, and 88.0 %, 98.4 %, 65.6 % and 85.7 %, respectively, with 24.8 IU/mL of Lac activity at 6 days of degradation. While using PVA-AA immobilized bacterium the reduction in pollutants; 61.0 %, BOD5; 75.9 %, COD; 76.5 %, TKN; 86.0 %, TOC; 97.9 %, phenol; 62.3 %, lignin and 89.8 %, color respectively with 18.5 IU/mL Lac activity was observed. The content of heavy metals after treatment with immobilized bacterium was also reduced significantly. FTIR analysis of wastewater samples showed that bacterial culture may degrade toxic aromatic compounds significantly. The toxicity data demonstrated that the paper industry wastewater was phytotoxic and cytotoxic in nature, but after treatment, it was reduced significantly.

Treatment of lignin enriched paper industry wastewater by electrocoagulation: Modelling approach and economic evaluation

Present work covers the treatment of lignin enriched paper industry wastewater (LEPIW) using electrocoagulation (EC) process with stainless steel (SS) electrodes. In this study, EC operation is optimized in term of % chemical oxygen demand (COD) removal and treatment cost (USD/kg COD removed). Single parameter study has been performed to study the effect of process parameters on % COD removal and treatment cost. Central composite design (CCD) of design of expert (DOE) has been used to corelate the input (time, initial COD, solution pH and current) and output parameters (% COD removal and treatment cost). Single parameter study states that maximum % COD removal of 84.4 & 77% is achieved in 40 & 60 min for initial COD:500 &1000 mg/L while 74, 66.7 & 58% can be achieved in 100 min for initial COD of 2000, 3000 & 4000 mg/L, respectively under optimum condition (solution pH:7, current: 1 A). Cost analysis summarizes that treatment cost decreases with increase in initial organic load (2.036, 2.075, 1.554, 1.247 & 1.127 USD/kg COD removed for initial COD of 500, 1000, 2000, 3000 & 4000 mg/L, respectively) at optimum condition. The caloric study states 2.31and 3.25 J/mg can be generated from the sludge and scum produced during EC process. DOE software suggests − 6.66–6.79% & − 16.73–7.95% error between experimental and designed value for % COD removal and treatment cost.

Catalytic Ozonation in Pulp and Paper Industry Wastewater Treatment: A Bibliometric Analysis

AbstractThe pulp and paper industry is one of the most significant industrial water polluters, generating large volumes of wastewater with high levels of organic pollutants, suspended solids, and other contaminants. Catalytic ozonation has emerged as a promising technique for the treatment of pulp and paper industry wastewater. Numerous reviews have presented the research on catalytic ozonation; however, open literature is missing a bibliometric analysis. Therefore, this article presents a bibliometric analysis of the research available on catalytic ozonation in pulp and paper industry wastewater treatment. A total of 578 documents extracted from the Scopus database have been examined via VOSviewer, MS Excel, and Rstudio to identify the research trends, influential authors, and research institutions in the field. The results reveal that the number of publications on the topic has increased significantly in recent years. This study also identified several influential authors, institutions, and highlighted future research directions in the field. Overall, the study provides insights into the state of research on catalytic ozonation in pulp and paper industry wastewater treatment and could help guide future research efforts in this area.

Evaluation of Bio-Membrane System Efficiency Optimized With Nanotechnology for Treatment of Pulp and Paper Industry Wastewater

Background & Aims: The membrane adsorption bioreactor (MABR) process is the integration of biological treatment and membrane technology. Accordingly, in this study, an MABR was employed for the pulp and paper industry wastewater treatment. Materials and Methods: The purchased powdered activated carbon (PAC) was added to the system as an adsorbent which improved the flux of the membrane. Results: Based on the obtained results, the organic compounds were successfully removed by the average removal of 62% and 86% without and with an adsorbent, respectively. Moreover, the activated sludge was prepared from the Babol-Toyoor Slaughterhouse wastewater treatment, and adding the PAC to the activated sludge led to the better performance of the MABR system by providing a proper condition for microorganism growth. Monitoring the mixed liquid suspended solids during the process demonstrated that increasing mixed liquor suspended solids (MLSS) increased the contaminant removal rate. Conclusion: Overall, the presence of PAC could prevent microorganisms from accumulating on the membrane surface.

Paper industry wastewater treatment by electrocoagulation and aspect of sludge management

The paper production process comprises various manufacturing steps and generates an enormous amount of effluent, which consists of a large variety of contaminated chemicals. The higher color and chemical oxygen demand (COD) of the wastewater create a negative effect on all living forms and the natural environment. Electrocoagulation is a versatile process for the elimination of color and COD content from wastewater. In this study, the EC treatment has been used to identify the ideal conditions using several process variables such as pH, current density, time, and the dose of electrolyte. COD and color were reduced by up to 68% and 94%, respectively. Afterward, the treated water was compared with the standards of the world health organization (WHO) and the central pollution control board (CPCB) to find out the suitability of treated water for reuse for farming purposes. Germination tests of mung beans were conducted, and it was observed that the EC treated water is suitable for irrigation. The corrosion rate of mild steel was determined to be 2.85 mils/year, which has shown the short life span of mild steel electrodes. Furthermore, sludge produced by the EC process was analyzed and characterized for physicochemical analyses by using a variety of analytical techniques. The 69.93% iron content of the sludge was also recovered using the acid digestion method. After the physicochemical analyses, it was observed that sludge could also be utilized as a compelling supplement for plant growth, energy recovery, and industrial applications. According to this study, treated water could be a powerful alternative for reducing freshwater consumption in agricultural areas and increasing water availability in water-scarce areas. Effect of operating parameters on electrocoagulation treatment of pulp and paper industry wastewater, treated water and sludge management. • The higher COD and color 68% and 94%, respectively, were removed from wastewater by using EC treatment. • The greater removal of pollutants occurred at a near neutral pH. • It was observed that there was an encouraging improvement in the biodegradability index of wastewater after EC process. • Treated water is found to be suitable for reuse in agriculture. • The produced sludge could be a compelling supplement for plant growth, energy recovery, and industrial applications.

Hydrothermal carbonization of pulp and paper industry wastewater treatment sludges - characterization and potential use of hydrochars and filtrates

The pulp and paper industry’s mixed sludge represents waste streams with few other means of disposal than incineration. Hydrothermal carbonization (HTC) could be advantageous for the sludge refinement into value-added products, thus complementing the concept of pulp and paper mills as biorefineries. Laboratory HTC was performed on mixed sludge (at 32% and 15% total solids) at temperatures of 210–250 °C for 30 or 120 min, and the characteristics of the HTC products were evaluated for their potential for energy, carbon, and nutrient recovery. The energy content increased from 14.9 MJ/kg in the mixed sludge up to 20.5 MJ/kg in the hydrochars. The produced filtrates had 12–15-fold higher COD and 3–5-fold higher volumetric methane production than untreated sludge filtrates, even though the methane yield against g-COD was lower. The increased value of the hydrochars in terms of energy content and carbon sequestration potential promote HTC deployment in sludge treatment and upgrading.

IoT Online Monitoring System on Pulp and Paper Industry Wastewater Treatment Plant

As one of the largest wastewater producers in the world, the pulp and paper industry need to monitor the waste that they generated. To carry out this monitoring process, the majority of the pulp and paper industry still uses conventional offline methods to measure parameters in their wastewater treatment plants. The monitoring procedure is carried out by taking samples from the factory wastewater treatment plant and testing these samples in the laboratory. This procedure is very prone to errors caused by human. This method also cannot detect any violation, problem, or disturbance of the wastewater parameters in real time. In addition, in 2018, the Indonesian Ministry of Environment and Forestry issued a regulation requiring the pulp and paper industry to use a real-time online monitoring system for its wastewater treatment plant.
 This paper presents an implementation of the system. There are several parameters that must be measured, two of them are pH and TSS (Total Suspended Solids). To measure these parameters, the regulation states that the online measurement system is carried out using the relevant electric probe sensor. Then the measurement results are displayed online on a specified platform hence that users can observe the results. This implementation uses a pH sensor to measure pH and a conductivity sensor to measure TSS. A conductivity sensor is used as a substitute due to the high cost of TSS sensor. This article analyses also the accuracy of the measurement.

Effects of nickle, nickle-cobalt and nickle-cobalt-phosphorus nanocatalysts for enhancing biohydrogen production in microbial electrolysis cells using paper industry wastewater

Paper industries are water-intensive industries that produce large amount of wastewater containing dyes, toxicity and high nutrient content. These industries require sustainable technology for their waste disposal and MEC could be one of them. However, effective MEC operation at neutral pH and ambient temperature requires economical and efficient cathodes that are capable to treat indusial wastewater along with recovery of energy/biohydrogen. Co-deposits of Nickel, Nickel–Cobalt and Nickel–Cobalt–Phosphorous on the surface of SS and Cu base metals distinctly were used as cathodes in MEC for the concurrent treatment of real paper industry wastewater and biohydrogen production. MECs were utilized in batch mode at neutral pH, applied voltage of 0.6 V and 30 ± 2 °C temperature with paper industry wastewater and activated sludge as microbial sources. The fabricated Nickel–Cobalt–Phosphorous gives the higher hydrogen production rate of 0.16 ± 0.002 m3(H2) m−3d−1 and 0.14 ± 0.002 m3(H2) m −3d −1 respectively, with ~33–42 % treatment efficiency for a 500 ml wastewater in 7-day batch cycle in both the cases; while it is lowest in the case of the control cathodes (SS1 (0.07 ± 0.002 m3(H2) m−3d−1) & Cu1 (0.06 ± 0.004 m3(H2) m−3d−1)). It was also found that fabricated cathodes have the capability to treat industrial wastewater at ambient conditions efficiently with higher energy recovery. Prepared cathodes show enhanced hydrogen production and treatment efficiency as well as are competitive to some reported literature.

Fenton and photo-Fenton processes integrated with submerged ultrafiltration for the treatment of pulp and paper industry wastewater

Excessive amounts of wastewater produced by the paper industry, often containing a wide range of toxic and recalcitrant pollutants based on raw materials used, should be subjected to efficient treatment processes before discharging to the environment. This experimental work examined hybrid Fenton and photo-Fenton enhanced (UVC254 and UVA365) UF system performances in treating raw wastewater from pulp and paper industry by membrane oxidation reactor (MOR). By response surface analyses of Taguchi experimental design, the systems were compared onto hybrid efficiencies, in settings optimized for maximal responses with minimum chemical needs, regarding the performance metrics of TOC and COD removal efficiencies and UF water flux. Organics were removed slightly better than Fenton in both photo-Fenton, and H2O2 and Fe2+ spends per TOC were accomplished as more efficient than anticipated in every MOR system. Optimal TOC-COD removals were found as 64.0–74.9% by 85.2 L/m2h at Fenton system, and as 66.5–76.1% by 138.1 L/m2h at UVA-Fenton, while 69.7–82.1% by 90.0 L/m2h at UVC-Fenton with the lowest chemical spending. Hybrid MORs studied were at desirable operational costs of 2.11, 4.15 and 3.13 $/kg removed COD in Fenton, UVA-Fenton and UVC-Fenton systems, respectively, corresponding to the demineralisation costs of 0.0075–0.0143 $/g TOC removed. This study revealed that by synergistic MOR performances, effluents, after pH adjustment, are directly dischargeable in sewage infrastructure ending with complete treatment. In a near future, such innovative approaches towards industrial wastewater treatments, at less resource demands, will unambiguously gain importance, as pressures to reuse wastewater increase and discharge limits become stricter.

Integrating phytoremediation into treatment of pulp and paper industry wastewater: Field observations of native plants for the detoxification of metals and their potential as part of a multidisciplinary strategy

This work aimed to explore the use of native herbs for the removal of heavy metals from pulp and paper industry wastewater, with the view of applying them as part of a multidisciplinary approach for detoxification. Results showed that after in-situ phytoremediation by the native herbs, the heavy metal, and metalloid contents in the wastewater were reduced by almost 60%. Heavy metal analysis of the plant tissues revealed that Fe accumulation was highest in all the tested plants. In general, the bioconcentration factor (BCF) was higher than one (>1) for all the metals except for Cd, suggesting most of the metals were concentrated in the plant tissues. In particular, As was concentrated significantly in Momordica doica and Cannabis sativa with elevated BCF of 269.46 and 131.20, respectively. High translocation factor (>1) was observed in P. hysterophorus and Tribulus terrestris for Cr (5.63) and Cd (7.53), respectively. Results showed most of the native plants examined in this study had hyperaccumulating tendency. Transmission electron microscope analysis of plant root tissues showed abundant metal depositions in the root cell wall, cytoplasm, and vacuole as strong evidence of the in-situ phytoremediation capability of these plants. Antioxidants activities of the plants such as superoxide dismutase, catalase, hydrogen peroxidase, peroxidase, and ascorbate peroxidase production were also noted to be higher than the control. These results support the use of native plants as a novel green process that can be integrated into the multidisciplinary treatment of hazardous industrial wastewater in the polluted sites.

In-situ toxicity assessment of pulp and paper industry wastewater on Trigonella foenum-graecum L: Potential source of cytotoxicity and chromosomal damage

This work aimed to study in-situ toxicity assessment of pulp and paper industry wastewater on Trigonella foenum-graecum L. Physico-chemical analysis of wastewater revealed high pH (8.1), total suspended solids, total dissolved solids, biochemical oxygen demand and chemical oxygen demand (89, 2160, 8670 and 25600 mg L−1 , respectively), electrical conductivity (2156 ms cm−1), and heavy metal (mg L−1) contents as Fe (79.61), Zn (49.06), Cu (6.07), Cd (6.07), Mg (19.66), and Ni (6.43), which were higher than compare to control The major pollutants detected via GC–MS analysis were hexadecanoic acid, octadecanoic acid, nonacosane, and β-sitosterol trimethylsilyl ether. UV–Vis spectrophotometry and Fourier transform infrared spectroscopy analyses of the wastewater confirmed the presence of residual organic and inorganic pollutants. The cytotoxicity and genotoxicity of the wastewater for plants were also assessed and revealed chromosomal and cytological aberrations in wastewater-treated T. foenum-graecum L. The accumulation of metals in and the effects of such accumulation on the physiology of T. foenum-graecum L. plants irrigated with wastewater were also studied, and it was concluded that antioxidant enzyme activity, chlorophyll, protein content, and dry weight were reduced in wastewater irrigated T. foenum-graecum L. plants compared to those in the control (fed with normal water). Scanning and transmission electron microscopy analyses of plant roots, root nodules, and stomata revealed the accumulation of heavy metals on the surfaces and in tissues. The present study highlights the urgent necessity of proper treatment of paper and pulp industry wastewater before their disposal into water bodies to control the damage to environment and aquatic life.

Use of paper mill sludge and sewage sludge powder as nitrogen and phosphorus sources with bacterial consortium for the treatment of paper industry wastewater

Abstract In this work, urea and diammonium phosphate (DAP) was replaced with paper mill sludge (PMSP) and sewage sludge powders (SWSP) individually as the source of nitrogen and phosphorous and treated by using a consortium isolated from i) sediment of final discharge (ii) sediment of secondary sludge (iii) sediment of equalization tank and named as Bacillus sp. IITRDVM-5, Pseudomonas sp. IITRDVM-10, and Pseudomonas stutzeri IITRDVM-16. The optimum conditions for treatment of the sequence batch biological process were: 48 h reaction time, temperature 37 °C, 150 rpm, and pH 7.0 ± 0.2 using 8% consortium inoculum. The maximum reductions in total organic carbon (TOC), chemical oxygen demand (COD), biochemical oxygen demand (BOD5day), and color at PMSP 3.16 g/500 mL were 79.7, 78.3, 83.2, and 73.9% whereas at SWSP 1.392 g/500 mL were 72.6, 71.4, 76.1 and 69.3% respectively compared to their respective controls. Both PMSP and SWSP individually showed a higher reduction in TOC, COD, BOD5day, lignin, total phenol, adsorbable organic halids (AOX), nitrogen, phosphate, and color compared to the final discharge of paper industry wastewater. Besides, a 74.2% reduction was observed in Kraft lignin (2000 ppm) prepared with MSM at a reaction time of 48 h. Fourier transforms infrared spectrophotometry (FTIR) was done to observe the significant changes in the functional groups of organic pollutants after the treatment of the wastewater samples. Finally, phytotoxicity analysis of the final discharge of the paper industry, untreated and treated wastewater sample was studied on seed (Vigna radiata) germination in which treated effluent showed lesser phytotoxicity.

Treatment of Pulp and Paper Industry Wastewater by using Fenton Method

The pulp and paper industry wastewater has not met the environmental uality standards set by the government so it may causes pollution to the environment; therefore, it is necessary to find a better wastewater treatment. The problem of this study is how to find the wastewater treatment alternative in order to get a more effective and efficient treatment. Fenton reagents are H 2 O 2 compounds (hydrogen peroxide) with iron catalysts and is one of the Advance Oxidations Process (AOPs) methods, which can be used as an alternative to process wastewater from the pulp and paper industry. In this study, the ratio of Fenton reagent molar concentration, temperature, and stirring time were varied, with stirring speed of 300 rpm, Fenton reagent volume of 25 mL, and pH set at 3. The visible parameters in this study were COD and TSS degradation. From this study, the best ratio of Fenton reagent is 1:2000, where this ratio can reduce the COD from 1002 mg/L to 176.05 mg/L and the TSS from 125 mg/L to 49.3 mg/L. This value has met the environmental quality standards for the pulp and paper industry set by the Indonesian government.

Pulp and paper industry wastewater treatment: use of microbes and their enzymes

AbstractPulp and paper industry is coming under one of the most water polluting industries, and generated wastewater is highly toxic in nature. The paper mill requires huge quantity (~50–60 m3of water to produce one ton of paper) of water, and accordingly huge quantity of chemical contaminated wastewater is discharged. The paper mill effluents have identified 240–250 chemicals in different stages of paper making. Various chemical constituents such as high chemical oxygen demand, biochemical oxygen demand, AOX, chlorinated compounds, color, suspended materials, lignin and their derivatives are released in the wastewater. The present review study is focused on the paper mill processes, wastewater generation and its effective treatment by microorganisms. The biological treatment has been identified as cost-effective and eco-friendly methods for the degradation of xenobiotic compounds for paper mill wastewater. Various studies have been performed so far to investigate the complex nature of wastewater by the application of bacteria, fungi and their enzymes at industrial scale. Therefore, the article discussed the importance of biological method as an effective technique for the degradation of paper mill wastewater.

Esparto paper industry wastewater treatment by adsorption onto powdered activated carbon

ABSTRACT The discharge of Esparto paper industrial wastewater (EPIW) of SNCPA Company of Kasserine – Tunisia in nature without any treatment can cause harmful effects to the environment. To reduce this danger, several treatment processes have been implemented, in particular, the adsorption technique. The present original study consists of using powdered activated carbon (PAC) to treat EPIW. The tests were carried out on different chemical oxygen demand (COD) concentration of EPIW ranging from 2 to 20 g/L. The influence of initial COD concentration, adsorbent dose, pH and contact time were investigated at temperature of 25 ± 2°C. The equilibrium results were modelled and assessed via Freundlich, Langmuir, Temkin and Dubunin–Radushkevich isotherms models. The error analysis was evaluated by three error functions: the average relative error deviation, the Marquardt’s percent standard error deviation and the Sum of the squares of the errors. The results showed that COD removal efficiency, maximum adsorption capacity and colour removal rate were 94%, 190 mg/g and 90%, respectively, for pH = 6, an adsorbent dose of 75 g/L, initial COD concentration of 9.3 g/L and contact time of 60 min. Besides, the main characteristics values of treated EPIW (BOD, TCOD, pH and Salinity) at natural conditions were 200 ± 30 mg O2/L, 1300 ± 50 mg O2/L, 7.2 ± 0.1 and 1.7 g/L ± 0.1, respectively, which were below the ISO-14,000 standards conditions for release in public sewerage system. Furthermore, both the higher value of correlation coefficients (R2) and the lower value of SSE have shown that Freundlich model provided the best fits to adsorption experimental results.

Modeling and optimizing electro-persulfate processes using Fe and Al electrodes for paper industry wastewater treatment.

In this study, the treatment of paper industry wastewaters by the electrocoagulation (EC) process with a strong oxidant, persulfate addition, was investigated. Persulfate was activated by dissolution of Fe and Al from electrodes during the process. Central composite design method, being one of the response surface methods, was applied for the optimization of process parameters and the development of a mathematical model for chemical oxygen demand (COD) removal from paper industry wastewaters. The effects of S2O8 -2/COD ratio, current, pH, and reaction time, being the variables of process, were assessed on the efficiency of contaminant removal. For COD removal in EC processes in which Fe and Al electrodes were used, the model's correlation coefficients (R2) were determined as 90.14% and 87.46%, respectively. As the result of experimental study actualized under optimum conditions determined by the model in order to obtain maximum contaminant removal, COD removal efficiencies were determined as 63.5% and 72.8% respectively for the Fe electrode (S2O8 -2/COD ratio: 1.25, current: 4.14 A, pH: 6, and reaction time: 5 minutes), and the Al electrode (S2O8 -2/COD ratio: 0.5, current: 4.25 A, pH: 7.25, and reaction time: 25 minutes). Electro-activated persulfate process is an appropriate treatment alternative for COD removal from paper industry wastewaters.

Perspectives on Membrane Bioreactor Potential for Treatment of Pulp and Paper Industry Wastewater: A Critical Review

The pulp and paper wastewater contains various organic and inorganic compounds in considerable amounts. Membrane bioreactor (MBR) technology has been used extensively for various industrial wastewater treatments due to its ability to produce appropriate effluent according to water quality regulations. Pulp and paper wastewater can be successfully treated by MBR in different conditions according to the wastewater and MBR characteristics. However, a major drawback in the use of MBR is membrane fouling, which leads to the reduction of effluent permeate flux. Fouling factors need to be considered because they are the major problems affecting the MBR performance. Besides, the performance of MBR can be increased by wastewater pretreatment methods and addition of a fouling reducer. In this paper, the application of aerobic and anaerobic MBR for pulp and paper wastewater treatment and membrane fouling has been reviewed. It has been found that the advantages of MBR over conventional biological treatment processes have made this technology popular for pulp and paper wastewater treatment.