Topic WQ-1

White Paper Topic: Manganese Treatment Standard

Development Team: K. Brady, R. Kleinmann, D. Sweeney, B. Means, C. Cravotta and G. Geidel

Date: October 21, 2005

Problem Definition:

Describe the nature of the issues or problems:

• Is Mn truly a surrogate for other trace & heavy metals?
• Is Mn biologically toxic and if so, at what concentrations?
• Treatment for Mn results in substantially increased treatment costs.
• Treatment for Mn results in increased sludge volume and subsequent sludge disposal issues.
• Treatment for Mn results in discharging high concentrations of Na and Ca.
• At the moment Mn concentration limits are specified by regulation. Could EPA modify its regulations to be more flexible in terms of effluent limits and use site-specific in-stream limits as an option?

Why is it an ADTI priority:

It is expensive to treat for Mn and the environmental benefit, at least in terms of aquatic life, is questionable. Additionally there are some negative aspects to Mn treatment (in addition to direct treatment costs), such as additional sludge handling and discharge of treatment chemicals to streams (e.g., Na). States with limited resources may be better off spending limited resources treating a greater number of sites to a pH sufficient to remove iron and aluminum, rather than taking that same pool of money and treating to a pH sufficient to achieve Mn removal. Industry may benefit economically from being able to treat specifically for the other contaminants that Mn is allegedly the surrogate for.

What are the technical issues?

• At what level is Mn toxic to aquatic organisms?
  • US EPA does not have a freshwater aquatic toxicity standard for Mn
• Should there be one? If so, what are the criteria and what is the science behind the number?
• Can other metals (e.g., Zn, Ni, Cd) be removed at a pH less than required for Mn removal?
  • If these metals are a problem it may be cheaper to simply treat to remove them at a lower pH than to treat for Mn at a high pH.

Potential Approaches to Solving the Problem:

OSM held a Workshop in the spring of 2005 to bring together Federal, State, Industry and outside experts to examine the manganese water treatment issue. Aspects that were examined are:

The U.S. Environmental Protection Agency is currently reviewing the effluent guidelines for manganese and additional research needs may arise from that process.

Cost of Project:

Provide a cost estimate for project scenarios: To be determined.

Time Required:

Provide a schedule/timeline to complete project scenarios. To be developed

Selected References

• American Fisheries Society, 1979. A Review of the EPA Red Book: Quality Criteria for Water. American Fisheries Society.
• Buikema, A.L., J. Cairns, Jr., G.W. Sullivan, 1974. Evaluation of Philodina acuticornis (Rotifera) as a bioassay organism for heavy metals. Water Resour. Bull. 10, p. 648-661.
• Clarke, R.M., 1974. The effects of effluents from metal mines on aquatic ecosystems in Canada: A literature review. Fish. Mar. Ser. Tech. Rep. 488, 150 p.
• Clement Associates, 1985. Chemical, physical and biological properties of compounds present at hazardous waste sites. Prepared for U.S. EPA, Washington, D.C., 312 p.
• Davies, P.H., 1976. The need to establish heavy metal standards on the basis of dissolved metals. Pages 93-126. In: Toxicity to biota of metal forms in natural waters. Proc. Worksop, Duluth, MN, Int. Joint Comm., Great lakes Res. Advisory Board. Windsor, Ontario, 329 p.
• National Academy of Sciences, National Academy of Engineering, 1973. Water quality criteria 1972. EPA Ecol. Res. Series EP_R3-73-033. U.S. Environmental Protection Agency, Washington, DC, 594 p.
• Reimer, Peter S., 1999. Environmental Effects of Manganese and Proposed Freshwater Guidelines to Protect Aquatic Life in British Columbia. M.S. Thesis, University of British Columbia.
• Stauber, J.L. and T.M. Florence, 1987. Mechanism of toxicity of ionic copper and copper complexes to algae. Marine Biology, Vo. 94, p. 511-519.
• Quality Criteria for Water, 1978 (EPA "Red Book"), EPA