Wards Island WWTP located in Manhattan has been in operation since 1937 and treats up to 275 MGD. The treatment plant has two remote grit chambers, which remove large solids and screenings. The grit chambers are located on the FDR Drive and 110th Street in Manhattan and at St. Ann’s Street in the Bronx. Wastewater enters the two grit chambers and is then routed underneath the East River to convey flow to the treatment plant.
The climber bar screens currently installed at the Bronx Grit Chamber & Manhattan Grit Chamber blind rapidly during high-flow, wet weather events, leading to flooding of the chambers and damage to equipment and must be replaced with more reliable screens. The Bronx & Manhattan Grit Chambers, part of the Wards Island WWTP, have been in operation since 1937. Each of the Bronx & Manhattan Grit Chambers consists of four (4) parallel grit channels. Each grit channel is equipped with hydraulically operated inlet & outlet sluice gates, one front-raked, climber-type bar screen, & grit collection equipment.
Under Contract WI-280 “Reconstruction of Manhattan & Bronx Grit Screens at Wards Island WWTP”, new continuously cleaning Headworks Mahr bar screens were installed. These new bar screens will allow better screenings collection & management of screenings removal, as well as minimize flooding of the grit chambers due to screen-blinding during heavy-rain events. The number and timing of grit channels down for bar screen installation needed to be coordinated so that the plant can continue to meet treatment demands.