Streamlining the process

For years, New York’s Long Island has been troubled by pollution stemming from toxic dumping and improper handling of industrial wastes. The pollution had the potential to adversely affect the island’s groundwater and drinking water via three major source aquifers close to the Earth’s surface.

Posillico Materials LLC, Farmingdale, New York, recognized the need to address mounting concerns over Long Island’s ground pollution and landfill capacity, and in 2019 the company opened a wash plant on the island to help clean it up. Recently, the company invested in a Hydro:Tip wet processor from CDE, based in Northern Ireland, to further its cleaning capabilities.

The dedication to cleaning up the island, its use of a wash plant and its effort to improve its operations garnered the company recognition earlier this year when Posillico was named 2022 C&D Recycler of the Year by the Construction & Demolition Recycling Association (CDRA), Chicago.

In announcing the award, the CDRA said the addition of the wash plant showed Posillico’s willingness to take a risk to recover more materials and added that the company’s research and development department is actively looking for more materials to recycle.

“We are continuously looking for opportunities that fit our strategic goals and to bring innovative solutions to the industry in the way we know how,” says Robert Tassey, wash plant manager for Posillico’s Farmingdale facility.

Established in 1946, Posillico is a fourth-generation family business that provides various integrated services, including heavy civil work for the public and private sectors and environmental remediation, paving, drilling and utilities contracting. The company receives material from construction sites and catch basins along highways in New York.

The construction of the wash plant coincided with a 2018 joint investigation between the New York District Attorney’s Office, the New York State Department of Environmental Conservation (DEC) and the Suffolk County Police Department into a conspiracy to illegally dump solid waste in various locations across Long Island. The monthslong investigation, known as “Operation Pay Dirt,” resulted in a 130-count indictment against 30 individuals and nine corporations for illegally disposing of solid waste at 24 locations, 19 of which are residential, four commercial and one school, according to Suffolk County.

The harmful substances found in the waste included arsenic, beryllium, cadmium, cobalt, chromium, copper, lead, nickel, zinc and mercury.

A thorough process

Posillico’s operations include five permanent concrete recycling operations that each have their own crushing systems and supply recycled-aggregate for various markets, two hot-mixed asphalt, or HMA, plants that use recycled asphalt pavement in their mixes. The company’s Farmingdale wash plant accepts excavation waste, uncontaminated materials, contaminated fill, vacuum truck waste, dredge spoils and mixed loads.

CDE’s Hydro:Tip is designed so operators can process wet materials, including mud, fluid and clay in a cost-effective and responsible manner, facilitating the recovery of sand and aggregate that can be resold to generate additional revenue streams. The Hydro:Tip can process 20 tons of material per hour and enables hydro excavation fleets to set up closer to extraction sources to reduce transport time, cost and fuel emissions, CDE says. 

Before the company invested in the system, Tassey says preprocessing and stabilizing a hydro-excavated load took up to 45 minutes and was weather-dependent. The company now can process varying amounts of material per load through the Hydro:Tip in about 15 minutes.

The process begins with a hauler dumping material into what Tassey describes as a giant hopper with several spray nozzles and jets that liquefy the material to make it a homogenous slurry. The material then goes into a sizing screen that allows the liquids, mud and sand-sized particles to fall through with the help of rinsing bars. The material that remains, including brick, gravel and asphalt, gets rinsed with spray nozzles and stockpiled. 

The material filtered out of the sizing screen gets collected into a sump that feeds it through hydro cyclones that further separate sand from mud and liquid. Tassey says the process also removes chemical contamination, such as petroleum.

“With the addition of the Hydro:Tip, we’re now able to dewater those slurries, separate the liquid from the solids, process the water directly into our wash plant and then handle the solid material in the same way we would with our other incoming fill,” Tassey said. “It’s the cleanest, safest, most effective and efficient way to manage hydro excavated waste on Long Island.”

The sand then is discharged onto a dewatering screen—a piece of equipment that vibrates the remaining water out of the sand. This results in washed, deslimed sand. The discharged mud and water are put into a tank that Posillico then pumps to its onsite water treatment plant to clean and polish the water.

“The Hydro:Tip is an extension of our full-scale wash plant,” Tassey says. “It is specifically designed to take a large volume of oversaturated material and handle it in a short period of time.”

Tassey says the equipment removes various contaminants to recover up to 85 percent of hydrovac material. The remaining 15 percent of the material, called filter cake, tends to retain the organic contaminants and is disposed of out-of-state.

Since opening, Tassey says the system handles about 75 to 100 loads monthly of varying types of solids and liquids. However, demand for the company’s services has grown due to the reduced downtime between loads.

“We are able to handle four times the amount of loads with the Hydro:Tip than we were previously,” Tassey says. “The hardest part of operating this equipment is keeping up with the demand that we now have after opening this portion of the plant up.”

The company’s C33 concrete sand is used by the concrete and asphalt market. Tassey says the gravel Posillico produces comes in three different sizes and is used in various applications. The company produces 3/8-inch gravel, 3/4-inch stone and a large offering ranging from 2 inches to 4 inches in thickness. Tassey says the 3/8-inch and the 3/4-inch concrete are used in commercial construction as raw materials and as backfill for tanks and retaining walls. The washed oversize material is used for tracking pads and drainage material.

While operating the Hydro:Tip equipment has been relatively smooth, Tassey says the main obstacle was the logistics of dumping material at the small site. Posillico’s Farmingdale site is built on 4 acres and the Hydro:Tip equipment takes up a 50-foot-by-50-foot portion of the site. The remaining space is taken up by the main wash plant, product stockpiles and traffic lanes for customer trucks. The company had to develop a new method for vehicles to enter the facility to dump their material, including building the Hydro:Tip into an existing retaining wall where the vac trucks now can dump.

Operating costs for the equipment include electricity, an operator and maintenance. Tassey says because the Hydro:Tip is a batch process, operating costs are low since it only uses energy when it is running.

The company says another benefit of the Hydro:Tip is that it created more space at the facility. Before using the new equipment, the company used to stabilize material in berms until they could be taken to the wash plant. This prevented trucks from coming in because there were capacity issues. The new equipment removes this problem by processing the material immediately and sending what remains to the wash plant.

Overall, the Hydro:Tip has improved the quality of the company’s service and safety because the equipment doesn’t require the driver to get into the berm to clean the back the truck to make sure the material has gone into it, Tassey says.

“Our company's safety culture is really paramount to everything we do,” he adds. “We really didn't realize how risky and how hazardous the old way of dumping trucks [into a berm] was until we began researching ways to elevate that bottleneck in our process.”

Previously, Tassey emphasized the importance of Posillico’s facility and processing material due to the growing population in New York and what he called an aging infrastructure. “There’s going to be a ton of material that needs to be processed, and it needs to be processed responsibly and efficiently. The way to do that is to recycle it through a plant like ours.”