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To: Members & Affiliates
Biosolids Committee
From: National Office
Date: December 21, 1999
Subject: PROPOSED DIOXIN STANDARD FOR BIOSOLIDS
Reference: RA 99-24

On December 15, 1999 U.S. Environmental Protection Agency (EPA) Administrator Carol Browner issued a proposed rule to limit dioxin and dioxin-like compounds in biosolids that are land applied. Specifically, EPA proposes to set a limit of 300 part per trillion (ppt) toxic equivalents (TEQ) for 29 specific congeners of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and coplanar PCBs, and to require minimum monitoring, record keeping and reporting requirements, for dioxins in biosolids that are land applied. The proposed rule does not contain additional limits for biosolids that are being placed in surface disposal units or incinerated.

It should be noted that in 1994, 114 biosolids samples from POTWs owned/operated by AMSA members were analyzed for dioxin, furans and 3 coplanar PCBs. The average dioxins concentration was 113 ppt (TEQ), while the mean concentration was 78 ppt (TEQ). Three of the 114 samples in the AMSA study had dioxins concentrations in excess of 300 ppt TEQ.

Background
In compliance with section 405 of the Clean Water Act, EPA published the Standards for the Use or Disposal of Sewage Sludge, known as the Round One sewage sludge regulation, in February 1993. The Round One regulation set limits for metals, pathogens and total hydrocarbons for land application, surface disposal and incineration of sewage sludge.

Section 405 of the Clean Water Act also requires a Round Two regulation for pollutants not previously regulated in Round One. As the result of a citizen's suit, EPA is required to propose Round Two regulations by December 15, 1999, and to take final action by December 15, 2001. In November 1995, EPA notified the court that, based on risk assessment results, the Agency was considering further regulations only for dioxins.


Proposal
The proposed rule would require facilities which prepare biosolids for land application to test the biosolids for dioxins, and also to perform periodic monitoring to determine the level of dioxins. The proposal sets a limit of 300 parts per trillion toxic equivalents of dioxins, above which biosolids may not be applied to the land. All facilities would be required to test the level of dioxins present in their biosolids before the biosolids could be land applied except:

    (1)     treatment plants treating less than one million gallons per day of wastewater, and

    (2)     small businesses which prepare less than 290 dry metic tons of sewage sludge annually.

The proposed rule would require facilities finding levels of dioxins between 30 and 300 ppt in their biosolids to monitor annually for dioxins, while facilities that find less than 30 ppt of dioxins would be required to monitor once every five years.
   
Based on risk assessments, the Agency is not proposing additional numeric standards or management practice requirements for dioxins in biosolids that are to be placed in surface disposal units or incinerated. Also, the the Agency is requesting comment on whether no numeric standards are appropriate with respect to regulating dioxins for land application of sewage sludge (see page 40 of attached EPA proposed rule).

Request for Comments
EPA is requesting comments 60 days from the date of publication of the proposed rule in the Federal Register (FR publication is expected in early January). AMSA's Biosolids Committee is interested in providing comprehensive AMSA comments on the Round II proposal and requests your input on key issues including, but not limited to:

  • Establishing a cap of 300 ppt TEQ dioxins for land applied sewage sludge that will protect a highly exposed individual from an incremental cancer risk of not greater than 1.7x10-5 (page 13);
  • Using EPA Analytical Method 1613B for the chlorinated dioxin and dibenzofuran congeners and EPA Analytical Method 1668 or 1668A for co-planar PCB congeners (page 16);
  • Requiring two consecutive years of monitoring results under 30 ppt TEQ before allowing a reduced monitoring schedule (page 17);
  • Assumption that the level of dioxins in sewage sludge is relatively constant over time and may possibly be decreasing (page 17);
  • Whether existing monitoring requirements are clarified by separating §503.16(a) into two paragraphs or if the proposed change unintentionally changes the substance of the frequency of monitoring provisions currently in §503.16(a)(1) (page 17);
  • Information on the dioxin content, annual application rates, numbers and sizes of sites, and applications per site for sewage sludge from treatment works with a flow rate of one MGD or less and whether to exempt small treatment works from both the initial monitoring requirements and the dioxin limit for land application.
  • EPA's proposed designation of small treatment works as one with a flow rate of one MGD or less, and its proposed designation of other small sludge preparers that are not treatment works as those preparing sewage sludge for land application in an amount of 290 dry metric tons or less annually (page 20);
  • Information on exposure pathways not evaluated, including direct risks to livestock, soil organisms, wildlife, and plants, resulting from dioxins in sewage sludge that is land applied or incinerated (pages 27, 34);
  • Proposing no action in regulating dioxins in sewage sludge that is placed in a surface disposal unit or incinerated in a sewage sludge incinerator (pages 33, 36);
  • Whether EPA should establish numeric limits for dioxins in sewage sludge for all use or disposal methods (page 39);
  • Proposing no action for dioxins in sewage sludge that is land-applied (page 40);
  • Whether there are any privately-owned treatment works with flows greater than one MGD that also have revenues less than $6 million. If such facilities are operating, we request information on flow, revenues, and sludge disposal methods (page 46);
  • Data on the cost to switch from land application to alternative use or disposal practices (compared to EPA assumption of $189 per dry metric ton to switch to co-disposal with municipal solid waste) (page 45);
  • Potential impacts of the proposed rule on small entities and on issue related to such impacts (page 43);
  • Consensus methods that are suitable for compliance monitoring for determining concentrations of dioxins, furans, and coplanar PCBs in sewage sludge (page 58).

If you are interested in providing comment on the proposal, please provide your comments to the AMSA National Office no later than January 28, 2000. The Biosolids Committee is especially interested in hearing from those members that are near or above the 300 ppt TEQ threshold to so that we can discuss the impacts of the land application restrictions in the proposal.

AMSA member agency comments will be collated into a comprehensive AMSA response to EPA. Comments should be addressed to Mark Hoeke via fax (202/833-4657) or e-mail mhoeke@amsa-cleanwater.org. If you have any questions, please contact Mark Hoeke at 202/833-9106.

 

Attachments:

  • Standards for the use or disposal of sewerage sludge (PDF ~105 KB)

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