Town of Riverhead - Producing Class A Biosolids at the Riverhead Water Resource Recovery Facility (RWRRF)

Negative Declaration

Suffolk County - The Town of Riverhead Sewer District, as lead agency, has determined that the proposed Producing Class A Biosolids at the Riverhead Water Resource Recovery Facility (RWRRF) will not have a significant adverse environmental impact. The Town of Riverhead Sewer District (District) has been in the forefront of the sustainability movement by recently upgrading their Riverhead Water Resource Recovery Facility (RWRRF) from a tertiary treatment facility with surface water discharge to a wastewater reuse facility by adding a second 450,000 gallons per day (gpd) outfall to divert highly treated effluent from the facility to the neighboring golf course, further reducing the total nitrogen load to the protected Peconic River while also preserving groundwater supplies normally utilized for golf course irrigation purposes. To continue with this objective, the district is proposing to seek funding to upgrade the RWRRF process to produce Class A, Exceptional Quality (EQ), biosolids from their sewage sludge utilizing the ThermAer system, a two-step autothermal thermophilic aerobic digestion (ATAD) process (the Proposed Action). Based on the feasibility study conducted to evaluate the Class A biosolids processes and conceptual site plan, the Proposed Action would include site improvements on the RWRRF site including: construction of a new biosolids control facility and booster pump station, renovations to existing tank facilities to accommodate the new treatment processes, construction of a biosolids storage area and installation of piped connections from the new facilities into the existing treatment infrastructure of the RWRRF. Site work includes:

• Existing structures will be repurposed for all the main tanks for the ThermAer process (ThermAer, BiofiltAer and the Storage Nitrification/Denitrification Reactor (SNDR)). The Thickened Sludge Holding Tank (TSHT) onsite will be repurposed for the ThermAer reactor with a diameter of 39' and side water depth of 17'. An out of service covered digester at RWRRF will be repurposed for the SNDR reactor with a diameter of 40' and a side water depth of 17'. The 30' diameter Scavenger Sludge Holding Tank (SSHT) will be repurposed as the BiofiltAer.

• A new 28' by 67' two-story biosolids control building will be located on the east side of the SNDR reactor and house recirculation pumps, a foam control pump, two transfer pumps, two feed pumps and CoolAer heat exchanger used in the process, as well as the electrical power and control elements (mechanical and control panel).

• Two process blowers that previously serviced the sludge holding tanks will be replaced for the reactors remaining in the scavenger/thickened sludge tanks blower room attached to the west side of the proposed SNDR reactor.

• A new reuse water booster pump station will be sited on the eastern side of the site.

• It is anticipated that the dewatered biosolids will be temporarily stored onsite within an enclosure sited in a 125' x 250' (31,250 SF) cleared, fenced in area adjacent to the entrance to the RWRRF. In order to protect the stockpile from moisture; a 100' x 122' shelter structure anchored on a heavy-duty reinforced concrete pad with 6' high perimeter walls for truck and machine traffic are proposed.

• The proposed stockpile area is enclosed by a 6-foot-high chain-link fence with double-leaf access gate exterior to the RWRRF.

Construction is anticipated to occur within an 18-month timeframe during which a trailer and staging area will be present on vacant areas within the RWRRF site. In additional to site improvements noted above, additional short lengths of site disturbance will be made to allow for installation of new piping connections. The project is located at 2 River Avenue, in the Town of Riverhead, New York.