Recycling of bleach plant filtrates by electrodialysis removal of inorganic non-process elements.

PDF Version Also Available for Download.

Description

Water use in the pulp and paper industry is very significant, and the U.S. pulp and paper industries as well as other processing industries are actively pursuing water conservation and pollution prevention by in-process recycling of water. Bleach plant effluent is a large portion of the water discharged from a typical bleached kraft pulp mill. The recycling of bleach plant effluents to the kraft recovery cycle is widely regarded as an approach to low effluent bleached kraft pulp production. The focus of this work has been on developing an electrodialysis process for recycling the acidic bleach plant effluent of bleached ... continued below

Physical Description

32 pages

Creation Information

Tsai, S. P.; Pfromm, P.; Henry, M. P.; Fracaro, A. T.; Swanstrom, C. P. & Moon, P. March 4, 2002.

Context

This report is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided by UNT Libraries Government Documents Department to Digital Library, a digital repository hosted by the UNT Libraries. It has been viewed 29 times , with 5 in the last month . More information about this report can be viewed below.

Who

People and organizations associated with either the creation of this report or its content.

Sponsor

Publisher

Provided By

UNT Libraries Government Documents Department

Serving as both a federal and a state depository library, the UNT Libraries Government Documents Department maintains millions of items in a variety of formats. The department is a member of the FDLP Content Partnerships Program and an Affiliated Archive of the National Archives.

Contact Us

What

Descriptive information to help identify this report. Follow the links below to find similar items on the Digital Library.

Description

Water use in the pulp and paper industry is very significant, and the U.S. pulp and paper industries as well as other processing industries are actively pursuing water conservation and pollution prevention by in-process recycling of water. Bleach plant effluent is a large portion of the water discharged from a typical bleached kraft pulp mill. The recycling of bleach plant effluents to the kraft recovery cycle is widely regarded as an approach to low effluent bleached kraft pulp production. The focus of this work has been on developing an electrodialysis process for recycling the acidic bleach plant effluent of bleached Kraft pulp mills. Electrodialysis is uniquely suited as a selective kidney to remove non-process elements (NPEs) from bleach plant effluent before they reach the chemical recovery cycle. Using electrodialysis for selective NPE removal can prevent the problems caused by accumulation of inorganic NPEs in the pulping cycle and recovery boiler. In this work, acidic bleach plant filtrates from three mills using different bleaching sequences based on chlorine dioxide were characterized. The analyses showed no fundamental differences in the inorganic NPE composition or other characteristics among these filtrates. The majority of total dissolved solids in the effluents were found to be inorganic NPEs. Chloride and nitrate were present at significant levels in all effluent samples. Sodium was the predominant metal ion, while calcium and magnesium were also present at considerable levels. The feasibility of using electrodialysis to selectively remove inorganic NPEs from the acidic bleach effluent was successfully demonstrated in laboratory experiments with effluents from all these three mills. Although there were some variations in these effluents, chloride and potentially harmful cations, such as potassium, calcium, and magnesium, were removed efficiently from the bleach effluents into a small-volume, concentrated purge stream. This effective removal of inorganic NPEs can enable the mills to recycle bleach effluents to reduce water consumption. The electrodialysis process also effectively retained up to 98% of the organics and can reduce the organic discharge in the mill wastewater. By using suitable commercially available electrodialysis membranes, there were no indications of rapid or irreversible membrane fouling or scale formation, even in extended laboratory scale operations up to 100 hours. Results of laboratory experiments also showed that commercially available membranes properly selected for this process would have good stability to withstand the potentially oxidative conditions of the filtrate. A pilot-scale field demonstration was also conducted at a southern mill, using the D0 filtrate from the bleach plant. During the field demonstration we found serious membrane stack clogging problems, which apparently were caused by fine fibers that escaped through the 5-micron pre-filters, although such a pre-filtration method had been satisfactory in the laboratory tests. Additional R&D is recommended to address this pre-filtration or clogging issue with systems approaches integrating pre-filtration, other separation methods, and stack design. After the pre-filtration/clogging issue is overcome, laboratory development and pilot demonstration are recommended to optimize the process parameters and to evaluate the long-term process parameters. The key technical issues here include membrane lives, control and mitigation of fouling and scaling, and cleaning-in-place protocols.

Physical Description

32 pages

Source

  • Other Information: PBD: 4 Mar 2002

Language

Item Type

Identifier

Unique identifying numbers for this report in the Digital Library or other systems.

  • Report No.: ANL/ES/RP-106995
  • Grant Number: W-31-109-ENG-38
  • DOI: 10.2172/793088 | External Link
  • Office of Scientific & Technical Information Report Number: 793088
  • Archival Resource Key: ark:/67531/metadc742972

Collections

This report is part of the following collection of related materials.

Office of Scientific & Technical Information Technical Reports

Reports, articles and other documents harvested from the Office of Scientific and Technical Information.

Office of Scientific and Technical Information (OSTI) is the Department of Energy (DOE) office that collects, preserves, and disseminates DOE-sponsored research and development (R&D) results that are the outcomes of R&D projects or other funded activities at DOE labs and facilities nationwide and grantees at universities and other institutions.

What responsibilities do I have when using this report?

When

Dates and time periods associated with this report.

Creation Date

  • March 4, 2002

Added to The UNT Digital Library

  • Oct. 19, 2015, 7:39 p.m.

Description Last Updated

  • March 30, 2016, 3:23 p.m.

Usage Statistics

When was this report last used?

Yesterday: 0
Past 30 days: 5
Total Uses: 29

Interact With This Report

Here are some suggestions for what to do next.

Start Reading

PDF Version Also Available for Download.

Citations, Rights, Re-Use

Tsai, S. P.; Pfromm, P.; Henry, M. P.; Fracaro, A. T.; Swanstrom, C. P. & Moon, P. Recycling of bleach plant filtrates by electrodialysis removal of inorganic non-process elements., report, March 4, 2002; Illinois. (digital.library.unt.edu/ark:/67531/metadc742972/: accessed December 10, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.