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Draft Air Quality Permit 6372-C2/O - DC Water and Sewer Authority

Friday, March 16, 2018


Draft Air Quality Permit 6372-C2/O, District of Columbia Water and Sewer Authority (DC Water), Construction and operation of biosolids handling facilities at the Blue Plains Advanced Wastewater Treatment Plant, 5000 Overlook Avenue SW

Notice is hereby given that, pursuant to 40 C.F.R. Part 51.161, D.C. Official Code §2-505, and 20 DCMR §210, the Air Quality Division (AQD) of the Department of Energy and Environment (DOEE), located at 1200 First Street NE, Washington, DC, intends to issue permit No. 6372-C2/O to the District of Columbia Water and Sewer Authority (DC Water) to construct and operate Biosolids Handling Facilities (BHF). The equipment described below is located at the Blue Plains Advanced Wastewater Treatment Plant, 5000 Overlook Avenue SW, Washington DC 20032. The contact person for the facility is Meena Gowda, Principal Counsel, at (202) 787-2628.

Equipment to be Permitted

  • Combined Heat and Power (CHP):
  • Three (3) Solar Mercury 50 Combustion Gas Turbines (CT) rated at 46.3 MMBtu/hr (HHV) heat input firing digester gas (DG) or a combination of digester gas and natural gas;
  • Three (3) Heat Recovery Steam Generators (HRSGs) equipped with supplemental firing by Duct Burners rated at 21 MMBtu/hr (HHV) heat input each, firing DG;
  • One (1) Auxiliary Boiler (AB) rated at 62.52 MMBtu/hr (HHV) heat input, firing DG and 61.79 MMBtu/hr (HHV) heat input firing natural gas (NG); and
  • One (1) Siloxane Destruction Flare (SF) rated at 6.14 MMBtu/hr heat input, firing DG


  • Main Process Train (MPT):
  • Two (2) Emergency Flares rated at126 MMBtu/hr heat input each, firing DG.
  • One (1) Raw Sludge Blending, Screening and pre-dewatering process;
  • Four (4) CAMBI  Thermal Hydrolysis Process (THP) trains;
  • Four (4) 3.8 million gallon Anaerobic Digesters; and
  • One (1) 44,800 scfm Bioscrubber Odor Scrubber (MPTOS).


  • Final Dewatering Facility:
  • Sixteen (16) Belt Filter Presses (BFP);
  • One (1) 54,000 scfm Dual Stage Chemical Scrubber - Final Dewatering Facility Odor Scrubber (FDFOS); and
  • One (1) new Spent Wash Water Concrete Collection Tank.


  • Lime Storage Silos
  • Installation of  two (2) new lime storage silos; 
  • Installation of  Silo Particulate Control Devices; and


  • Building Make-Up Air Handling Units (Space Heaters) Less than 5 MMBtu/hr Heat Input with Equivalent Combined Full Load of 33.11 MMBtu/hr limited to 94.8 MMCF/yr, firing NG
  • Final Dewatering Facility (FDF): 12 units, 0.750 MMBtu/hr each, and 1 unit, 1.00 MMBtu/hr (10.00 MMBtu/hr total);
  • CHP Gas Condition Facility: 2 units, 0.70 MMBtu/hr each (1.40 MMBtu/hr total) ;
  • CHP Gas Blower Building: 1 unit,0.25 MMBtu/hr total heat requirement;
  • CHP Turbine Plant: 3 units, 0.70 MMBtu/hr each (2.10 MMBtu/hr total);
  • MPT Pre-Dewatering Building: 2 units, 3.52 MMBtu/hr each, and 1 unit, 3.17 MMBtu/hr (10.21 MMBtu/hr total);
  • Digestion Building: 1 unit, 2.20 MMBtu/hr total heat requirement;
  • Sludge Screening Building: 1 unit, 2.38 MMBtu/hr total heat requirement; and
  • Solids Blending Building: 4 units, 1.145 MMBtu/hr each (4.58 MMBtu/hr total)

This permit renewal is necessary because the amended construction Permit No. 6372-C-A2 issued on October 27, 2014 has expired. Additionally, DC Water requested several modifications to Permit No. 6372-C-A2 which resulted in potential increases of up to 3.47 tons of oxides of nitrogen (NOx) per year.

Due to on-going construction of permitted equipment, including the inherent need to operate certain equipment and processes for the purposes of demonstrating satisfactory performance, this permit is proposed to allow for both construction and operation of the covered equipment.


The following changes to previously established emission limits are proposed. These changes are proposed as revisions to a previously established “lowest achievable emission rate” (LAER) determination made pursuant to 20 DCMR 204 for the two emergency flares at the facility. These and other NOx limits contained in the permit are also intended to be proposed as “reasonably available control technology” (RACT) levels for NOx pursuant to 20 DCMR 805 for inclusion in the District of Columbia’s State Implementation Plant (SIP) found at 40 CFR 52, Subpart J through a different action. All other emission limits established in the previously issued permit to construct remain unchanged.

1.   Total allowable emissions of NOx from the permitted equipment will increase from 77.07 tons per 12-month rolling period to 80.54 tons per 12-month rolling period. This is an increase of 3.47 tons per year.


2.   Allowable hourly emissions of NOx from each of the two emergency flares will increase from 5.29 pounds per hour to 12.72 pounds per hour.

Total allowable emissions from the equipment covered by the permit are summarized in the table below:

Total 12-Month Rolling Emission Limits from Permitted Equipment1


12-Month Rolling Emissions Limit (tons/yr)

PM (Total)2














HAPs (Total)


1. The equipment covered consists of three Solar Mercury 50 gas turbines, three duct burners, one auxiliary steam boiler, one siloxane removal system, , two emergency flares, space heating units as referenced in this permit, two odor scrubbers (MPTOS and FDFOS), and two lime silo baghouses.

2. Total PM is the sum of the filterable PM and condensable PM

The application to construct and operate the BHF and the draft permit and supporting documents are available for public inspection at AQD and copies may be made available between the hours of 8:15 A.M. and 4:45 P.M. Monday through Friday. Interested parties wishing to view these documents should provide their names, addresses, telephone numbers and affiliation, if any, to Stephen S. Ours at (202) 535-1747.

Interested persons may submit written comments or may request a hearing on this subject within 30 days of publication of this notice. The written comments must also include the person’s name, telephone number, affiliation, if any, mailing address and a statement outlining the air quality issues in dispute and any facts underscoring those air quality issues. All relevant comments will be considered in issuing the final permit.

Comments on the proposed permit and any request for a public hearing should be addressed to:

Stephen S. Ours
Chief, Permitting Branch
- Air Quality Division

Department of Energy and Environment
1200 First Street NE, 5th Floor

Washington, DC 20002

[email protected]

No comments or hearing requests submitted after April 16, 2018 will be accepted.