This permit, issued to the City and County of Honolulu, is being modified pursuant to Hawaii Administrative Rules (HAR), Section 11-55-16 and Title 40 Code of Federal Regulations (40 CFR), Section 122.62(a)(2). The proposed major modification includes:

1. Removing the DDT maximum daily and average annual effluent limitations and revising the monitoring frequency from monthly to semi-annually pursuant to 40 CFR Section 122.62(a)(15) (specifically, excluding non- detects from RPA calculations);

2. Removing the chlordane maximum daily and average annual effluent limitations pursuant to 40 CFR Sections 122.62(a)(2) (specifically, consideration of additional data and new dilution study) and (a)(15) (specifically, (1) utilizing an RPA that projected daily maximum concentrations, thereby not considering the long exposure time associated with human health criteria for carcinogens (e.g. 70 years) and the fact that human health criteria for carcinogens is expressed as an annual average and (2) the treatment of non-detects in RPA calculations);

3. Revising the dieldrin maximum daily and average annual effluent limitations pursuant to 40 CFR Sections 122.62(a)(2) (specifically, consideration of additional data and new dilution study) and (a)(15) (specifically, (1) utilizing an RPA that projected daily maximum concentrations, thereby not considering the long exposure time associated with human health criteria for carcinogens (e.g. 70 years) and the fact that human health criteria for carcinogens is expressed as an annual average and (2) the treatment of non- detects in RPA calculations);

4. Removing the ammonia nitrogen maximum daily effluent limitations pursuant to 40 CFR Sections 122.62(a)(2) (specifically, utilization of additional data) and (a)(15) (specifically, the treatment of non-detects in RPA calculations);

5. Revising the enterococcus maximum daily and average monthly effluent limitations pursuant to 40 CFR Section 122.62(a)(2) (specifically, consideration of additional data and new dilution study);

6. Revising certain Whole Effluent Toxicity (“WET”) requirements, including for the Instream Waste Concentration (“IWC”) and test species pursuant to 40 CFR Section 122.62(a)(2) (specifically, consideration of additional information regarding projected changes to the treatment train and species sensitivities, and new dilution study); and

7. Removing Part I.5 of the 2014 Permit, “Planned Changes” pursuant to 40 CFR Section 122.62(a)(15) (specifically, to achieve consistency with 40 CFR 122.41(l)).

The draft modified permit shall expire on November 11, 2019.

In accordance with 40 CFR Sections 124.5(c)(2) and 122.62, only the conditions outlined above are being proposed for modification. Please note that DOH is only requesting comments on, or considering requests for a public hearing on, the items proposed for modification as described above.

Persons wishing to comment upon or object to the proposed modified SIWWTP NPDES permit or to request a public hearing, should submit their comments or requests in writing no later than 30 calendar days after the date of this notice, either in person or by mail, to:

Clean Water Branch
Environmental Management Division
Department of Health
2827 Waimano Home Road, Room 225
Pearl City, HI 96782

If DOH’s position is substantially unchanged after considering all timely written comments and all oral comments at any public hearing that may be held, then the DOH will issue the modified NPDES permit and this action will be final.