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Contract # 93-417

Contract Name:

Yonkers Combined Sewer Overflow

Agency:Westchester County Department of Public Works
Engineer:Savin Engineering, Inc.
Contract Amount:$7,731,066
Contract Completion:1999
Percent Completed By Ecco:80%%
Scope of Work:
This project consisted of structural, architectural and mechanical demolition of an existing Sewage Screening Building, which involved the removal of concrete tanks, structural steel, structural floor slabs, mechanical process piping, masonry walls and an active forty eight inch sewer pipe.
Reconstruction work consisted of the installation of a temporary bypass system during the installation of a new sixty inch prestressed concrete cylinder pipe for sewage overflow influent, the installation of steel sheeting within the confines of the building shell in order to excavate for the new chlorine contact tank, the construction of two, twenty two foot in diameter concrete swirl concentrator tank and a twenty five foot by eighty five foot concrete chlorine contact tank and the installation of an Odor Control System. Also included in the reconstruction work was the installation of brick, concrete cylinder block and pre-glazed masonry walls, the installation of mechanical process equipment (i.e.: bar screens, tide gates, stop logs, sump pumps, submersible mixers, centrifugal pumps, chemical feed pumps and four inch thru ten inch ductile iron process piping), the installation of sheet membrane roofing, skylights and roof hatches, the installation of a five ton overhead bridge crane and five, one ton monorail hoist systems, the installation of miscellaneous metals (i.e: aluminum handrails, fiberglass grating, structural steel supports and lintels, aluminum staircases and access hatches) and the painting of all finished surfaces.
Due to the proximity of an active sewer viaduct running alongside the length of the new chlorine contact tank area and working within the confines of the building, the installation of the steel sheeting system required a considerable amount of engineering and planning to achieve a proper installation.