This primary source comes from the Records of the Environmental Protection Agency.
National Archives Identifier:
546801Full Citation: Trickling Filters At The Back River Sewage Treatment Plant This Is The Primary Treatment Facility For The Baltimore Area; 2/1973; Records of the Environmental Protection Agency, Record Group 412. [Online Version, https://www.docsteach.org/documents/document/trickling-filters-at-the-back-river-sewage-treatment-plant-this-is-the-primary-treatment-facility-for-the-baltimore-area, May 4, 2024]