South Shore Water Reclamation Facility Overview

About the Bay Park Sewage Treatment Plant

Bay Park Treatment Plant

The Bay Park Sewage Treatment Plant (STP) is located in southern Nassau County, between 1st Avenue and the East Rockaway Channel. Figure 22.1 illustrates the Bay Park STP location and collection system boundary. The Bay Park STP handles flow from Nassau County Sewage Disposal Districts 1 and 2, serving an overall population of approximately 530,000 residents as well as some commercial entities.

The Sewage Disposal Districts 1 and 2 were built between 1949 and 1962, and include 22 pump stations. These districts are comprised of approximately 1,300 miles of local collection and trunk sewer lines. The collection system piping ranges from 8 in. to 84 in. in diameter. The trunk and interceptor system is generally made of reinforced concrete pipe, while the lateral sewer system is generally made of asbestos cement and clay pipe.

The Bay Park STP was constructed in the late 1940s to provide secondary treatment using the activated sludge process. Originally designed to treat 27 MGD, the plant was initially expanded in 1960 to provide additional plant capacity of up to 60 MGD. Recent construction projects have upgraded the plant capacity to treat an average daily flow of 70 MGD.

The massive tidal event caused by Superstorm Sandy resulted in flood waters compromising the electrical system of the plant, causing it to cease operation for approximately 50 hours. In that time the collection system became overburdened and caused overflow into some streets and homes throughout the collection system.

In response to the damage more than $830 million in federal and state aid was secured to repair and storm harden the plant. In addition Nassau County has undertaken a project to construct a protective earthen berm and wall around the perimeter of the plant.

The Bay Park Sewage Treatment Plant Process

The Bay Park STP has a permitted capacity of 70 MGD. The actual flow averaged over the past three years is approximately 59 MGD.

Preliminary treatment is accomplished using four mechanically-cleaned bar screens and three detritus tanks for grit removal. The bar screens can accommodate a maximum water depth of 9ft, 1in, and have a 1-in spacing between the bars. The grit tanks are each 35 ft in length by 35 ft in width with a sidewater depth of 4.5 ft. Screenings and grit are removed and disposed of at a landfill. Influent flow is pre-chlorinated using sodium hypochlorite.

Bay Park Treatment Process

Grit tank effluent flows to primary treatment consisting of eight bays of primary settling tanks. Each bay measures 17.5 ft by 160 ft, with a side water depth of 12.5 ft. The primary tanks are fitted with scum removal units. Influent flow is pre-chlorinated using sodium hypochlorite. Sludge from the primary tanks is pumped directly to the sludge digesters.

Secondary treatment consists of activated sludge using five aeration tanks equipped with bubble diffusers. The aeration tanks each have dimensions of 264 ft by 100 ft by 14 ft. Tanks No. 1 through 4 have 7 in. diameter ceramic fine bubble dome diffusers and the fifth tank has 9 in. diameter disc diffusers.

Following activated sludge treatment, wastewater flows to ten final settling tanks. Tanks No. 1 through 3 are 194 ft by 58 ft, with a side water depth of 12 ft. Tanks No. 4 through 6 are 197 ft by 58 ft, with a side water depth of 12 ft. And finally tanks No. 7 through 10 are 197 ft by 49 ft, with a side water depth of 12 ft.

Wastewater exiting from secondary treatment passes through four final effluent screens to remove any remaining solids prior to chlorination. These traveling water screens are 8 ft wide, with 1/8 in. openings. Sludge collected from secondary treatment is thickened in dissolved air floatation units before being transferred to the sludge digesters.

Plant effluent is disinfected using sodium hypochlorite before being discharged to Reynold’s Channel via an 84 in. diameter outfall pipeline approximately 2.3 miles long. Sludge generated at the Bay Park STP is processed using four high-rate anaerobic primary digesters and two secondary digesters. All digesters are equipped with floating covers.

Methane gas produced by anaerobic digestion is utilized by the Bay Park STP’s Power Generation Facility and the Central Heating Facility. Digested sludge is stored in two sludge storage tanks before it is dewatered by 12 belt filter presses. The dewatered sludge cake is trucked to an out-of-state facility for further processing into soil amendments.