Patapsco Grit Facility and Southwest Diversion Sewer Odor Control

Location: Baltimore, MD

Client: City of Baltimore Department of Public Works

Patapsco Grit FacilityCCJM was retained by the City of Baltimore to provide On-Call Mechanical Engineering Services.

The objective of this project was to prepare a comprehensive study to determine how to better control high levels of hydrogen sulfide (H2S) gas in order to improve working conditions inside the Patapsco Grit Building, and to minimize H2S and odors discharged from the Southwest Diversion Sewer (SWDS) into the Grit Building.

CCJM evaluated a total of twelve (12) odor control alternatives. They are Tank Covers and Wet Scrubber system, Hydrogen Peroxide (H2O2), Air Injection, Iron Salts (FeCl3, FeCl2), Nitrate Salt, Thioguard® (Mg(OH)2), Influent Hydrogen Sulfide Stripping Structure, Effluent Weir Containment, Hydritreat HS Process®, Purafil®, Biomagic® and OHxyPhogg®.

CCJM recommended ferric chloride feed system be installed at the Patapsco Pumping Station (PS) for odor control at the Grit Building and portion of the Southwest Diversion Sewer. The proposed ferric chloride feed point will be located approximately three miles upstream of the Patapsco Wastewater Treatment Plant (WWTP). By adding ferric chloride, it would precipitate both hydrogen sulfide and phosphorus out of the Plant influent, thus the ferric chloride dosage for phosphorus trimming at the Plant would be reduced.