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Bengt-erik Bengtsson - One of the best experts on this subject based on the ideXlab platform.

  • toxicity of conventional Elemental Chlorine free and totally Chlorine free kraft pulp bleaching effluents assessed by shortterm lethal and sublethal bioassays
    Environmental Toxicology and Chemistry, 1999
    Co-Authors: Maria Tarkpea, Britta Eklund, Margareta Linde, Bengt-erik Bengtsson
    Abstract:

    The toxicity of nine effluents from Swedish kraft-pulp mills using conventional, Elemental Chlorine-free (ECF) and totally Chlorine-free (TCF) bleaching processes was studied. Effluents represented six different processes: conventional-softwood 30% ClO2; ECF-softwood; TCF-hardwood, for which all the samples were taken before and after secondary treatment; conventional-softwood 8% ClO2; TCF-softwood O3/H2O2; and TCF-softwood H2O2. Comparison of effluents, which had not undergone secondary treatment, suggested that those from mills using conventional bleached pulp were the most toxic, with toxic emission factors (TEF) ≈ 1,000 according to the Microtox® test (AZUR Environmental, Carlsbad, CA, USA). In the acute Nitocra spinipes test, the conventional-softwood 8% ClO2 and the ECF-softwood effluents before secondary treatment were the most toxic, with TEF ≈ 700. In the reproduction test, N. spinipes was two to three times more sensitive than in the lethal test. The species most sensitive to the effluents investigated was the macroalga Ceramium strictum, with TEF values up to 3,000. The conventional effluent using a substitution of 8% ClO2 was the most toxic, and the TCF effluents were the least toxic. Degradation treatment of the ECF and TCF effluents for 28 d in the laboratory did not eliminate acute lethal effects on N. spinipes and the Microtox bacterium.

  • Toxicity of conventional, Elemental Chlorine‐free, and totally Chlorine‐free kraft‐pulp bleaching effluents assessed by shortterm lethal and sublethal bioassays
    Environmental Toxicology and Chemistry, 1999
    Co-Authors: Maria Tarkpea, Britta Eklund, Margareta Linde, Bengt-erik Bengtsson
    Abstract:

    The toxicity of nine effluents from Swedish kraft-pulp mills using conventional, Elemental Chlorine-free (ECF) and totally Chlorine-free (TCF) bleaching processes was studied. Effluents represented six different processes: conventional-softwood 30% ClO2; ECF-softwood; TCF-hardwood, for which all the samples were taken before and after secondary treatment; conventional-softwood 8% ClO2; TCF-softwood O3/H2O2; and TCF-softwood H2O2. Comparison of effluents, which had not undergone secondary treatment, suggested that those from mills using conventional bleached pulp were the most toxic, with toxic emission factors (TEF) ≈ 1,000 according to the Microtox® test (AZUR Environmental, Carlsbad, CA, USA). In the acute Nitocra spinipes test, the conventional-softwood 8% ClO2 and the ECF-softwood effluents before secondary treatment were the most toxic, with TEF ≈ 700. In the reproduction test, N. spinipes was two to three times more sensitive than in the lethal test. The species most sensitive to the effluents investigated was the macroalga Ceramium strictum, with TEF values up to 3,000. The conventional effluent using a substitution of 8% ClO2 was the most toxic, and the TCF effluents were the least toxic. Degradation treatment of the ECF and TCF effluents for 28 d in the laboratory did not eliminate acute lethal effects on N. spinipes and the Microtox bacterium.

Maria Tarkpea - One of the best experts on this subject based on the ideXlab platform.

  • toxicity of conventional Elemental Chlorine free and totally Chlorine free kraft pulp bleaching effluents assessed by shortterm lethal and sublethal bioassays
    Environmental Toxicology and Chemistry, 1999
    Co-Authors: Maria Tarkpea, Britta Eklund, Margareta Linde, Bengt-erik Bengtsson
    Abstract:

    The toxicity of nine effluents from Swedish kraft-pulp mills using conventional, Elemental Chlorine-free (ECF) and totally Chlorine-free (TCF) bleaching processes was studied. Effluents represented six different processes: conventional-softwood 30% ClO2; ECF-softwood; TCF-hardwood, for which all the samples were taken before and after secondary treatment; conventional-softwood 8% ClO2; TCF-softwood O3/H2O2; and TCF-softwood H2O2. Comparison of effluents, which had not undergone secondary treatment, suggested that those from mills using conventional bleached pulp were the most toxic, with toxic emission factors (TEF) ≈ 1,000 according to the Microtox® test (AZUR Environmental, Carlsbad, CA, USA). In the acute Nitocra spinipes test, the conventional-softwood 8% ClO2 and the ECF-softwood effluents before secondary treatment were the most toxic, with TEF ≈ 700. In the reproduction test, N. spinipes was two to three times more sensitive than in the lethal test. The species most sensitive to the effluents investigated was the macroalga Ceramium strictum, with TEF values up to 3,000. The conventional effluent using a substitution of 8% ClO2 was the most toxic, and the TCF effluents were the least toxic. Degradation treatment of the ECF and TCF effluents for 28 d in the laboratory did not eliminate acute lethal effects on N. spinipes and the Microtox bacterium.

  • Toxicity of conventional, Elemental Chlorine‐free, and totally Chlorine‐free kraft‐pulp bleaching effluents assessed by shortterm lethal and sublethal bioassays
    Environmental Toxicology and Chemistry, 1999
    Co-Authors: Maria Tarkpea, Britta Eklund, Margareta Linde, Bengt-erik Bengtsson
    Abstract:

    The toxicity of nine effluents from Swedish kraft-pulp mills using conventional, Elemental Chlorine-free (ECF) and totally Chlorine-free (TCF) bleaching processes was studied. Effluents represented six different processes: conventional-softwood 30% ClO2; ECF-softwood; TCF-hardwood, for which all the samples were taken before and after secondary treatment; conventional-softwood 8% ClO2; TCF-softwood O3/H2O2; and TCF-softwood H2O2. Comparison of effluents, which had not undergone secondary treatment, suggested that those from mills using conventional bleached pulp were the most toxic, with toxic emission factors (TEF) ≈ 1,000 according to the Microtox® test (AZUR Environmental, Carlsbad, CA, USA). In the acute Nitocra spinipes test, the conventional-softwood 8% ClO2 and the ECF-softwood effluents before secondary treatment were the most toxic, with TEF ≈ 700. In the reproduction test, N. spinipes was two to three times more sensitive than in the lethal test. The species most sensitive to the effluents investigated was the macroalga Ceramium strictum, with TEF values up to 3,000. The conventional effluent using a substitution of 8% ClO2 was the most toxic, and the TCF effluents were the least toxic. Degradation treatment of the ECF and TCF effluents for 28 d in the laboratory did not eliminate acute lethal effects on N. spinipes and the Microtox bacterium.

Rajesh Kumar Lohchab - One of the best experts on this subject based on the ideXlab platform.

  • Environmental Aspect of Using Chlorine Dioxide to Improve Effluent and Pulp Quality During Wheat Straw Bleaching
    Waste and Biomass Valorization, 2019
    Co-Authors: Daljeet Kaur, Nishi K. Bhardwaj, Rajesh Kumar Lohchab
    Abstract:

    Purpose This paper illustrates the need of using the agro waste (wheat straw) as a substitute for forest products in paper industry. It aims on using the soda-AQ pulping process for converting waste to fibrous pulp. Further, it emphasizes on use of Chlorine dioxide in place of Elemental Chlorine and hypochlorite during bleaching with aim of reducing the wastewater load and improving the pulp quality. Methods Complete chemical characterization of wheat straw was performed. The soda-AQ (anthraquinone) method was opted for cooking and to make a pulp of kappa number 13. The pulp was bleached with Elemental Chlorine and calcium hypochlorite based sequences. To study the impact of adding Chlorine dioxide on paper properties and effluent quality, Elemental Chlorine and hypochlorite were replaced with dioxide. The total Elemental Chlorine free bleaching sequence was also studied. The hand sheets were prepared to analyze the bleached and unbleached pulp properties using standard methodology. The effluent quality was studied by measuring the properties COD, BOD, TDS, TSS, TS, colour, lignin and adsorbable organic halides. Results Proximate chemical analysis of wheat straw showed that it contains holocellulose 67.3 ± 0.16%, hemicelluloses 39.2 ± 0.7%, cellulose 34.2 ± 0.9%, lignin content 14.9 ± 0.09% and ash 9.2% that mainly composed of silica (7.7%). With soda-AQ process a pulp with 53% yield and good strength properties was obtained. The bleached pulp of Chlorine dioxide based sequences was having better strength properties in comparison to Chlorine based sequences. Total replacement of Elemental Chlorine with Chlorine dioxide reduced the BOD (52%), COD (49%), colour (43%), lignin (57%) and AOX (63%). Conclusions Research concluded that wheat straw can be utilized by paper mills to combat the problem of waste management, air pollution due to its burning and issues of raw material for papermaking. Soda-AQ pulping method was found to be effective for preparing the wheat straw pulp. Use of Elemental Chlorine free bleaching may prove to be a reliable approach for better environmental management with high pulp characteristics.

  • Effect of incorporation of ozone prior to ECF bleaching on pulp, paper and effluent quality.
    Journal of Environmental Management, 2019
    Co-Authors: Daljeet Kaur, Nishi Kant Bhardwaj, Rajesh Kumar Lohchab
    Abstract:

    Abstract The pulp and paper industry is highly dependent on forest and water resources. It has more concerns on fair utilization of these resources and their conservation for its further expansion. Present study emphasizes on the use of rice straw (agro waste) in papermaking to protect wood based resources. It further deals with ozone bleaching (Z) prior to Elemental Chlorine free bleaching that proved to be significant in terms of reducing the effluent load specially the reduction in toxic, recalcitrant and carcinogenic compounds. Z based sequences resulted in pulp brightness of ∼85% that was 3.6% higher than the Elemental Chlorine free bleaching. Bleached pulps of Z based sequences were found to be having better strength properties than Elemental Chlorine based sequence and thus may be adopted as improved bleaching technology. The analysis of handsheets prepared after pulp bleaching was performed using X-Ray diffraction, ATR-FTIR and SEM. Incorporating ozone stage resulted in marked reduction of 58% and 63% in total solids in bleaching wastewater. Reduction of more than 80% in BOD, COD and adsorbable organic halides was achieved in Z based bleaching in comparison to Chlorine bleaching. The amount of chlorophenols, guaiacols, catechols, vanillins and syringols became negligible (approx. 90% reduction) in effluents of Z based bleaching sequences. The Chlorine dioxide followed by peroxide bleaching after Z stage was found to be the most promising to reduce the effluent load.

  • Environmental Aspect of Using Chlorine Dioxide to Improve Effluent and Pulp Quality During Wheat Straw Bleaching
    Waste and Biomass Valorization, 2018
    Co-Authors: Daljeet Kaur, Nishi Kant Bhardwaj, Rajesh Kumar Lohchab
    Abstract:

    This paper illustrates the need of using the agro waste (wheat straw) as a substitute for forest products in paper industry. It aims on using the soda-AQ pulping process for converting waste to fibrous pulp. Further, it emphasizes on use of Chlorine dioxide in place of Elemental Chlorine and hypochlorite during bleaching with aim of reducing the wastewater load and improving the pulp quality. Complete chemical characterization of wheat straw was performed. The soda-AQ (anthraquinone) method was opted for cooking and to make a pulp of kappa number 13. The pulp was bleached with Elemental Chlorine and calcium hypochlorite based sequences. To study the impact of adding Chlorine dioxide on paper properties and effluent quality, Elemental Chlorine and hypochlorite were replaced with dioxide. The total Elemental Chlorine free bleaching sequence was also studied. The hand sheets were prepared to analyze the bleached and unbleached pulp properties using standard methodology. The effluent quality was studied by measuring the properties COD, BOD, TDS, TSS, TS, colour, lignin and adsorbable organic halides. Proximate chemical analysis of wheat straw showed that it contains holocellulose 67.3 ± 0.16%, hemicelluloses 39.2 ± 0.7%, cellulose 34.2 ± 0.9%, lignin content 14.9 ± 0.09% and ash 9.2% that mainly composed of silica (7.7%). With soda-AQ process a pulp with 53% yield and good strength properties was obtained. The bleached pulp of Chlorine dioxide based sequences was having better strength properties in comparison to Chlorine based sequences. Total replacement of Elemental Chlorine with Chlorine dioxide reduced the BOD (52%), COD (49%), colour (43%), lignin (57%) and AOX (63%). Research concluded that wheat straw can be utilized by paper mills to combat the problem of waste management, air pollution due to its burning and issues of raw material for papermaking. Soda-AQ pulping method was found to be effective for preparing the wheat straw pulp. Use of Elemental Chlorine free bleaching may prove to be a reliable approach for better environmental management with high pulp characteristics.

  • Improvement in rice straw pulp bleaching effluent quality by incorporating oxygen delignification stage prior to Elemental Chlorine-free bleaching
    Environmental Science and Pollution Research, 2017
    Co-Authors: Daljeet Kaur, Nishi K. Bhardwaj, Rajesh Kumar Lohchab
    Abstract:

    Environmental degradation by industrial and other developmental activities is alarming for imperative environmental management by process advancements of production. Pulp and paper mills are now focusing on using nonwood-based raw materials to protect forest resources. In present study, rice straw was utilized for pulp production as it is easily and abundantly available as well as rich in carbohydrates (cellulose and hemicelluloses). Soda-anthraquinone method was used for pulp production as it is widely accepted for agro residues. Bleaching process during paper production is the chief source of wastewater generation. The chlorophenolic compounds generated during bleaching are highly toxic, mutagenic, and bioaccumulative in nature. The objectives of study were to use oxygen delignification (ODL) stage prior to Elemental Chlorine-free (ECF) bleaching to reduce wastewater load and to study its impact on bleached pulp characteristics. ODL stage prior to ECF bleaching improved the optical properties of pulp in comparison to only ECF bleaching. When ODL stage was incorporated prior to bleaching, the tensile index and folding endurance of the pulp were found to be 56.6 ± 1.5 Nm/g and 140, respectively, very high in comparison to ECF alone. A potential reduction of 51, 57, 43, and 53% in BOD_3, COD, color, and AOX, respectively was observed on adding the ODL stage compared to ECF only. Generation of chlorophenolic compounds was reduced significantly. Incorporation of ODL stage prior to bleaching was found to be highly promising for reducing the toxicity of bleaching effluents and may lead to better management of nearby water resources. Graphical abstract ᅟ

  • Reduction in chlorophenolic compounds during bleaching of rice straw pulp by replacing Elemental Chlorine with Chlorine dioxide
    International Journal of Environmental Science and Technology, 2017
    Co-Authors: Daljeet Kaur, Nishi Kant Bhardwaj, Rajesh Kumar Lohchab
    Abstract:

    Speedy running down of forest cover has put great stress on paper industry for finding new fibrous raw materials. Rice straw is an abundantly available lignocellulosic material especially in wood-short countries and can be utilized as an alternate fibre resource by paper mills. Bleaching is a crucial step in papermaking that involves the chemical reactions to reduce the colour of the pulp and makes it brighter for manufacturing writing and printing grade paper. Contrary to this, bleaching results into the formation of toxic, biorefractory and carcinogenic chlorolignin compounds that pose serious health hazards to aquatic life and human beings. A study was carried out using rice straw soda-AQ pulp for bleaching with sequence based on Elemental Chlorine (CEOPHH). Further, to reduce the wastewater pollution load, emphasis was given on replacement of Elemental Chlorine with Chlorine dioxide at the first bleaching stage (CD10EOPHH CD30EOPHH and CD50EOPHH) and Elemental Chlorine-free (ECF) bleaching (DEOPD). The study revealed that generation of chlorophenolic compounds was the highest in CEOPHH sequence followed by CD10EOPHH CD30EOPHH and CD50EOPHH, i.e. 6047, 4765, 4247 and 3864 mg/t, respectively. In DEOPD bleaching sequence, the generation of chlorophenolic compounds in wastewater was reduced to 421 mg/t. ECF bleaching had major impacts on reduction in chloroguaiacols (97%) and chlorophenols (92%) that were in the highest quantity in effluents of CEOPHH bleaching sequence. DEOPD bleaching was found to be a promising option for pulp and paper industry for cutting down the generation of chlorophenolic compounds in bleaching effluents.

Nishi Kant Bhardwaj - One of the best experts on this subject based on the ideXlab platform.

  • Effect of introducing ozone in Elemental Chlorine free bleaching of pulp on generation of chlorophenolic compounds
    Nordic Pulp & Paper Research Journal, 2020
    Co-Authors: Sandeep Tripathi, Nishi Kant Bhardwaj, Himadri Roy Ghatak
    Abstract:

    AbstractEffect of using ozone before Elemental Chlorine free (ECF) bleaching of oxygen delignified wheat straw pulp produced following soda-anthraquinone pulping on bleaching effluent and pulp properties was studied. The effluent generated during bleaching of pulp contains high amount of adsorbable organic halogens (AOX), chemical oxygen demand (COD), biochemical oxygen demand (BOD) and highly toxic chlorophenolic compounds. This study is aimed to utilise green chemistry approach during bleaching of one of the abundantly used agro residue wheat straw for improving the quality of bleaching effluent and pulp properties. Introducing ozone stage before ECF bleaching resulted in significant reduction of chloriphenolic compounds like chlorocatechols by 48.9 %, chloroguaiacols by 33.3 %, chlorovanillins by 28.4 % and chlorophenols by 26.7 % in the effluent compared to those of control. Incorporation of ozone before ECF bleaching BOD, COD, AOX and colour were reduced by 40.0 %, 41.1 %, 46.7 % and 57.8 %, respectively, as compared to control. Optical properties like brightness and whiteness of the pulp bleached using ozone were also improved by 2.5 units and 4.0 units, respectively as compared to that with control.

  • Utilization of sarkanda for making pulp and paper using Elemental Chlorine free and total Chlorine free bleaching processes
    Industrial Crops and Products, 2020
    Co-Authors: Nirmal S. Sharma, Sandeep Tripathi, Nishi Kant Bhardwaj
    Abstract:

    Abstract A lignocellulosic non-wood material sarkanda available in abundance as waste, was evaluated for chemical constituents, pulping behavior, morphological properties, bleaching behavior and paper handsheet strength properties. Present study reveals that sarkanda contains cellulose 36.2 ± 0.5 %, hemicelluloses 35.2 ± 0.41 %, lignin 21.2 ± 0.22 % and ash 8.2 ± 0.3 %. Soda-anthraquinone pulping of sarkanda using 15 % active alkali resulted in unbleached pulp with 14.7 kappa number, 16.0 cP viscosity and 54.6 % pulp yield. With use of Elemental Chlorine free bleaching sequence, OD0EOPD, final bleached pulp achieved 85.7 % ISO brightness, whereas, using total Chlorine free bleaching sequence, OZEOPPOPO, the brightness obtained was 81.9 % ISO. Elemental Chlorine free bleached sarkanda pulp had tensile index of 39.4 N m/g, burst index of 3.4 kN/g and tear index of 5.7 mN m2/g. The study exhibits that sarkanda has potential to be utilized for papermaking. Such approach of using non-wood raw material with Elemental Chlorine free bleaching and total Chlorine free bleaching sequences for papermaking can be a valuable approach for reducing pollutants generation, utilization of waste biomass and fulfillment of fibrous raw material requirement for paper industry.

  • Effect of different Elemental Chlorine-free bleaching sequences on pulp, effluent properties and their impact on index of global pollution.
    Environmental Science and Pollution Research, 2019
    Co-Authors: Sandeep Tripathi, Nishi Kant Bhardwaj, Himadri Roy Ghatak
    Abstract:

    Six Elemental Chlorine-free bleaching sequences were studied to see their effect on quality of pulp produced and quantity of pollutants generated during bleaching of wheat straw soda pulp. Impact of parameters like adsorbable organic halogens (AOX), chemical oxygen demand (COD), biochemical oxygen demand (BOD) and sodium adsorption ratio, pH and total dissolved solids generated during bleaching on environment as index of global pollution (IGP) was also studied. The purpose of the study was to investigate six Elemental Chlorine-free bleaching sequences to compare the pulp quality, effluent properties and their impact on environment. An oxygen delignification stage before D0EOPD bleaching sequence reduced the AOX, COD, colour and BOD by 44%, 42%, 36% and 33%, respectively, whereas an ozonation stage before bleaching reduced the same by 70%, 66%, 73% and 60%, respectively, as compared to those of control. The generation of pollutants as AOX, COD, colour and BOD was reduced further by 88%, 80%, 90% and 77%, respectively, with the use of short bleaching sequences (DD, DP and PD) as compared to those of control. The environmental impact as IGP with D0EOPD bleaching sequence was 2.65 which got reduced to 1.44 with bleaching sequence OZPD. Bleaching sequence OZD0EOPD was found the most effective for improving brightness and whiteness of the pulp, whereas short bleaching sequence OZPD found the most effective for reducing generation of pollutants during bleaching among different bleaching sequences studied. Graphical abstract.

  • Developments in Ozone-Based Bleaching of Pulps
    Ozone: Science & Engineering, 2019
    Co-Authors: Sandeep Tripathi, Nishi Kant Bhardwaj, Himadri Roy Ghatak
    Abstract:

    ABSTRACTThis paper summarizes the review of developments in the area of ozone-based Elemental Chlorine free (ECF) and total Chlorine free (TCF) bleaching of wood and non-wood pulps. Focused areas o...

  • Approaches for converting sugarcane trash, a promising agro residue, into pulp and paper using soda pulping and Elemental Chlorine-free bleaching
    Journal of Cleaner Production, 2019
    Co-Authors: Nishi Kant Bhardwaj, Daljeet Kaur, Smita Chaudhry, Mani Sharma, Satyajeet Arya
    Abstract:

    Abstract Industrialization and urbanization are the key drivers to threaten the environmental quality and natural resources. Traditionally, pulp and paper industry has been highly reliant on forest based resources for its escalation. Shortage of forest based raw materials, strict environmental regulations and policies have compelled the industry to seek for alternate raw materials for its production. Mills are now focusing on exploring the potential of different agro wastes such as cereal straws and bagasse etc. In present research, sugarcane trash, one of the most abundant agro residues in India, was investigated for its capability in pulping and bleaching. Chemical characterization of sugarcane trash showed that it contains 40.4% cellulose, 33.2% hemicelluloses, 17.4% lignin and 6.45% ash content with 2.76% silica. To cook sugarcane trash with soda pulping method, 14% alkali charge, 15 min time and 162 °C temperature was found to be optimum and pulp of kappa no. 19.8 was prepared that exhibited good strength properties. Bleaching of pulp was carried out using Elemental Chlorine (Cl2), hypochlorite and Chlorine dioxide (ClO2) based sequences. Replacement of Cl2 with ClO2 has significant impact on strength properties and effluent characteristics. Oxygen delignification stage was incorporated prior to ClO2 that resulted in improved optical properties of pulp with noticeable reduction in wastewater load. This paper elaborates the need of using sugarcane trash in paper mills with environment friendly pulping and bleaching processes to combat with the problem of waste management, wastewater load reduction during bleaching and substitute for wood based raw materials in papermaking.

Daljeet Kaur - One of the best experts on this subject based on the ideXlab platform.

  • Environmental Aspect of Using Chlorine Dioxide to Improve Effluent and Pulp Quality During Wheat Straw Bleaching
    Waste and Biomass Valorization, 2019
    Co-Authors: Daljeet Kaur, Nishi K. Bhardwaj, Rajesh Kumar Lohchab
    Abstract:

    Purpose This paper illustrates the need of using the agro waste (wheat straw) as a substitute for forest products in paper industry. It aims on using the soda-AQ pulping process for converting waste to fibrous pulp. Further, it emphasizes on use of Chlorine dioxide in place of Elemental Chlorine and hypochlorite during bleaching with aim of reducing the wastewater load and improving the pulp quality. Methods Complete chemical characterization of wheat straw was performed. The soda-AQ (anthraquinone) method was opted for cooking and to make a pulp of kappa number 13. The pulp was bleached with Elemental Chlorine and calcium hypochlorite based sequences. To study the impact of adding Chlorine dioxide on paper properties and effluent quality, Elemental Chlorine and hypochlorite were replaced with dioxide. The total Elemental Chlorine free bleaching sequence was also studied. The hand sheets were prepared to analyze the bleached and unbleached pulp properties using standard methodology. The effluent quality was studied by measuring the properties COD, BOD, TDS, TSS, TS, colour, lignin and adsorbable organic halides. Results Proximate chemical analysis of wheat straw showed that it contains holocellulose 67.3 ± 0.16%, hemicelluloses 39.2 ± 0.7%, cellulose 34.2 ± 0.9%, lignin content 14.9 ± 0.09% and ash 9.2% that mainly composed of silica (7.7%). With soda-AQ process a pulp with 53% yield and good strength properties was obtained. The bleached pulp of Chlorine dioxide based sequences was having better strength properties in comparison to Chlorine based sequences. Total replacement of Elemental Chlorine with Chlorine dioxide reduced the BOD (52%), COD (49%), colour (43%), lignin (57%) and AOX (63%). Conclusions Research concluded that wheat straw can be utilized by paper mills to combat the problem of waste management, air pollution due to its burning and issues of raw material for papermaking. Soda-AQ pulping method was found to be effective for preparing the wheat straw pulp. Use of Elemental Chlorine free bleaching may prove to be a reliable approach for better environmental management with high pulp characteristics.

  • Approaches for converting sugarcane trash, a promising agro residue, into pulp and paper using soda pulping and Elemental Chlorine-free bleaching
    Journal of Cleaner Production, 2019
    Co-Authors: Nishi Kant Bhardwaj, Daljeet Kaur, Smita Chaudhry, Mani Sharma, Satyajeet Arya
    Abstract:

    Abstract Industrialization and urbanization are the key drivers to threaten the environmental quality and natural resources. Traditionally, pulp and paper industry has been highly reliant on forest based resources for its escalation. Shortage of forest based raw materials, strict environmental regulations and policies have compelled the industry to seek for alternate raw materials for its production. Mills are now focusing on exploring the potential of different agro wastes such as cereal straws and bagasse etc. In present research, sugarcane trash, one of the most abundant agro residues in India, was investigated for its capability in pulping and bleaching. Chemical characterization of sugarcane trash showed that it contains 40.4% cellulose, 33.2% hemicelluloses, 17.4% lignin and 6.45% ash content with 2.76% silica. To cook sugarcane trash with soda pulping method, 14% alkali charge, 15 min time and 162 °C temperature was found to be optimum and pulp of kappa no. 19.8 was prepared that exhibited good strength properties. Bleaching of pulp was carried out using Elemental Chlorine (Cl2), hypochlorite and Chlorine dioxide (ClO2) based sequences. Replacement of Cl2 with ClO2 has significant impact on strength properties and effluent characteristics. Oxygen delignification stage was incorporated prior to ClO2 that resulted in improved optical properties of pulp with noticeable reduction in wastewater load. This paper elaborates the need of using sugarcane trash in paper mills with environment friendly pulping and bleaching processes to combat with the problem of waste management, wastewater load reduction during bleaching and substitute for wood based raw materials in papermaking.

  • Effect of incorporation of ozone prior to ECF bleaching on pulp, paper and effluent quality.
    Journal of Environmental Management, 2019
    Co-Authors: Daljeet Kaur, Nishi Kant Bhardwaj, Rajesh Kumar Lohchab
    Abstract:

    Abstract The pulp and paper industry is highly dependent on forest and water resources. It has more concerns on fair utilization of these resources and their conservation for its further expansion. Present study emphasizes on the use of rice straw (agro waste) in papermaking to protect wood based resources. It further deals with ozone bleaching (Z) prior to Elemental Chlorine free bleaching that proved to be significant in terms of reducing the effluent load specially the reduction in toxic, recalcitrant and carcinogenic compounds. Z based sequences resulted in pulp brightness of ∼85% that was 3.6% higher than the Elemental Chlorine free bleaching. Bleached pulps of Z based sequences were found to be having better strength properties than Elemental Chlorine based sequence and thus may be adopted as improved bleaching technology. The analysis of handsheets prepared after pulp bleaching was performed using X-Ray diffraction, ATR-FTIR and SEM. Incorporating ozone stage resulted in marked reduction of 58% and 63% in total solids in bleaching wastewater. Reduction of more than 80% in BOD, COD and adsorbable organic halides was achieved in Z based bleaching in comparison to Chlorine bleaching. The amount of chlorophenols, guaiacols, catechols, vanillins and syringols became negligible (approx. 90% reduction) in effluents of Z based bleaching sequences. The Chlorine dioxide followed by peroxide bleaching after Z stage was found to be the most promising to reduce the effluent load.

  • Environmental Aspect of Using Chlorine Dioxide to Improve Effluent and Pulp Quality During Wheat Straw Bleaching
    Waste and Biomass Valorization, 2018
    Co-Authors: Daljeet Kaur, Nishi Kant Bhardwaj, Rajesh Kumar Lohchab
    Abstract:

    This paper illustrates the need of using the agro waste (wheat straw) as a substitute for forest products in paper industry. It aims on using the soda-AQ pulping process for converting waste to fibrous pulp. Further, it emphasizes on use of Chlorine dioxide in place of Elemental Chlorine and hypochlorite during bleaching with aim of reducing the wastewater load and improving the pulp quality. Complete chemical characterization of wheat straw was performed. The soda-AQ (anthraquinone) method was opted for cooking and to make a pulp of kappa number 13. The pulp was bleached with Elemental Chlorine and calcium hypochlorite based sequences. To study the impact of adding Chlorine dioxide on paper properties and effluent quality, Elemental Chlorine and hypochlorite were replaced with dioxide. The total Elemental Chlorine free bleaching sequence was also studied. The hand sheets were prepared to analyze the bleached and unbleached pulp properties using standard methodology. The effluent quality was studied by measuring the properties COD, BOD, TDS, TSS, TS, colour, lignin and adsorbable organic halides. Proximate chemical analysis of wheat straw showed that it contains holocellulose 67.3 ± 0.16%, hemicelluloses 39.2 ± 0.7%, cellulose 34.2 ± 0.9%, lignin content 14.9 ± 0.09% and ash 9.2% that mainly composed of silica (7.7%). With soda-AQ process a pulp with 53% yield and good strength properties was obtained. The bleached pulp of Chlorine dioxide based sequences was having better strength properties in comparison to Chlorine based sequences. Total replacement of Elemental Chlorine with Chlorine dioxide reduced the BOD (52%), COD (49%), colour (43%), lignin (57%) and AOX (63%). Research concluded that wheat straw can be utilized by paper mills to combat the problem of waste management, air pollution due to its burning and issues of raw material for papermaking. Soda-AQ pulping method was found to be effective for preparing the wheat straw pulp. Use of Elemental Chlorine free bleaching may prove to be a reliable approach for better environmental management with high pulp characteristics.

  • Improvement in rice straw pulp bleaching effluent quality by incorporating oxygen delignification stage prior to Elemental Chlorine-free bleaching
    Environmental Science and Pollution Research, 2017
    Co-Authors: Daljeet Kaur, Nishi K. Bhardwaj, Rajesh Kumar Lohchab
    Abstract:

    Environmental degradation by industrial and other developmental activities is alarming for imperative environmental management by process advancements of production. Pulp and paper mills are now focusing on using nonwood-based raw materials to protect forest resources. In present study, rice straw was utilized for pulp production as it is easily and abundantly available as well as rich in carbohydrates (cellulose and hemicelluloses). Soda-anthraquinone method was used for pulp production as it is widely accepted for agro residues. Bleaching process during paper production is the chief source of wastewater generation. The chlorophenolic compounds generated during bleaching are highly toxic, mutagenic, and bioaccumulative in nature. The objectives of study were to use oxygen delignification (ODL) stage prior to Elemental Chlorine-free (ECF) bleaching to reduce wastewater load and to study its impact on bleached pulp characteristics. ODL stage prior to ECF bleaching improved the optical properties of pulp in comparison to only ECF bleaching. When ODL stage was incorporated prior to bleaching, the tensile index and folding endurance of the pulp were found to be 56.6 ± 1.5 Nm/g and 140, respectively, very high in comparison to ECF alone. A potential reduction of 51, 57, 43, and 53% in BOD_3, COD, color, and AOX, respectively was observed on adding the ODL stage compared to ECF only. Generation of chlorophenolic compounds was reduced significantly. Incorporation of ODL stage prior to bleaching was found to be highly promising for reducing the toxicity of bleaching effluents and may lead to better management of nearby water resources. Graphical abstract ᅟ