Riverhead Town is looking to turn sewage sludge into fertilizer.
The town board is considering a $7 million project that would provide the ability to turn sewage sludge into “Class A Biosolids” suitable for land application by farmers, growers, nurserymen and homeowners.
Currently, the town has its sewage sludge trucked to a landfill in Pennsylvania.
The new system would save the town about $520,000 per year in operation and maintenance costs, according to Riverhead Sewer District consulting engineers H2M. Even if the town finances the total cost of the project, it would still save $260,000 per year with debt service factored in, H2M director of wastewater engineering Christopher Weiss told the town board at yesterday’s work session. That assumes the town obtains low-interest financing through the State Environmental Facilities Corporation. Currently the EFC low-interest loan program interest rate is .36%, Weiss said.
Riverhead Sewer District Superintendent Michael Reichel said disposing of sewage sludge at off-island landfills will only become more difficult and expensive. He said he foresees a day when it will even become impossible. Landfills are becoming scarce and eventually no landfill will want sewage sludge.
“Conditioning” sludge to create Class A biosolids is a sustainable alternative, Reichel said.
The end product can be used locally, Weiss said.
The town currently treats sewage and “scavenger waste” — cesspool waste — at its facility on River Avenue. The recently upgraded facility — project that won national recognition for innocation and excellence — is rated to treat 1.6 million gallons per day.
The mix of liquids and solids that come into the facility is treated in a series of processes that separate liquids from solids and disinfect both.
The resulting liquid effluent — treated to drinking water standards — is discharged into the Peconic River pursuant to a discharge permit from the State Department of Environmental Conservation. During the warm weather months, 450,000 gallons per day of liquid effluent is used to irrigate the Indian Island county golf course adjoining the sewer plant.
The sludge, which is a mixture of liquid and solids, is thickened and dewatered to produce “sludge cake” that is 15-20% solids by volume. The sludge cake is trucked off the island for disposal in a Pennsylvania landfill.
The cost to haul the sludge cake from the site is a significant portion of the facility’s annual operating budget, with a current cost ranging between $600,000 and $650,000 per year, according to a feasibility study prepared by H2M.
That’s only going to get more expensive, Weiss said.
Long-haul disposal would not be entirely eliminated, but will be drastically reduced, according to the feasibility study.
Town board members agreed to authorize the preparation of a map and plan for the project, the first step in the design phase.
Take this video tour of the Riverhead sewage treatment plant in June 2015, before the $24 million upgrade completed in 2016.
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