Material Sand & Stone Corp.
The Material Sand & Stone Corp. produces construction sand and gravel, as well as asphalt paving mixtures, out of North Smithfield. The 105-acre parcel at 618 Greenville Road has been “extensively disturbed as a result of past and present gravel pit operations,” according to DEM.
A rock-crushing operation runs Monday through Saturday, with stone washing occurring intermittently and as weather permits from April to December. The operation, which uses water from the Woonasquatucket River, results in wastewater discharges.
During average precipitation, stormwater is contained on-site by berms, infiltration trenches, and retention basins. But site surveys and drainage calculations show stormwater discharge could occur during flooding events.
The facility’s discharges enter a series of sedimentation basins on-site before feeding out to the wetlands and back into the Woonasquatucket River, which lie to the north and west of the property. The Woonasquatucket River, according to the permit, is recognized as a “Class B” waterbody, which is suitable for fish and wildlife habitat, recreation, and “compatible industrial processes.” However, according to Rhode Island’s 2018-2020 list of impaired waters, the Woonasquatucket River does not support fish and wildlife habitat or primary recreation due to high levels of zinc and the presence of enterococcus.
Material Sand & Stone submitted a RIPDES permit application for these discharges June 8, 2020. DEM showed concern about the facility’s ability to meet limits for total iron and TSS, which serves as a metric for water column particles.
The facility plans to build new treatment ponds to better control the discharges. However, according to DEM, these ponds are only anticipated to lower effluent TSS levels to 41 milligrams per liter — still above the permitted monthly average of 25 milligrams per liter.
As per the permit, total iron and TSS would be monitored quarterly, along with flow rate, pH level, zinc, enterococci, nitrate, nitrite-nitrogen, and perchlorate.
Also, according to the permit, discharges should not discolor the Woonasquatucket River, or add any oil sheen, foam or floating solids. All discharge of detergents, asphalt plant wastewater, concrete truck wash water, and truck engine and undercarriage wash water to surface water is prohibited.
Inspections would occur annually, with additional regular inspection of sediment accumulation, vehicle entrances, seeded topsoil slopes, and the structural integrity of outfall locations, earthen berms, and barriers.