Technical Description:
- The Stormwater Management StormFilter®
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Originally founded in 1964 for handling building debris, Mazza Demolition, Transfer, Recycling and Scrap Metal has grown into a 50-employee company located near Tinton Falls, N.J. Today the company processes or recycles demolition debris, scrap metal, tires, concrete, yard debris and other recyclable materials. One of its toughest challenges is controlling runoff from oily scrap metal and oil dripping from customers’ trucks and its own heavy equipment. The owner, Dominick Mazza, knows the environmental damage that can be caused by polluted runoff and has taken steps to minimize it.
The Challenge
The Mazza facility borders on a wetland that also cuts inside the property. The site’s topography and the nature of the facility divide it roughly into three parts — one for recycling wood, concrete, mulch and other materials, another for recycling scrap metal, and a third for construction demolition transfer. Customers bring concrete, scrap metal, tires, brush, mulch, and tree stumps to a transfer station — a 46,000 square-foot building in the center of the site. Here employees separate recyclables from disposable materials. The company’s demolition division also brings construction materials to the transfer station.
Like all N.J. recycling operations, Mazza must meet an environmental regulation called the N.J. Pollution Discharge Elimination System code (NJAC 7:14A), as well as numerous other New Jersey Department of Environmental Protection (NJDEP) requirements. The regulation requires controlling stormwater runoff. “We do our best to assure that on-site scrap metal is clean and oil free,” said Mazza. “But minor oil leaks from customers’ trucks and company heavy equipment create pollutants that could drain onto the wetland.”
The Solution
Working with a N.J. engineering firm, Schoor DePalma, Inc., the company moved to comply with the stringent NJDEP requirements. The engineering firm found the site unique because of the variety of recyclables and the relative flatness of the property.
To meet the mandated requirements, the engineers recommended installing the Stormwater Management StormFilter®, a HDS and a detention pond. They also advised using catch basins to collect some runoff. This design addresses potential environmental concerns about runoff containing debris, dirt, metals, oil and grease, and is a recognized best management practice by N.J. and many other states.
According to Mazza, the Contech. systems were relatively easy to install and the team completed all the work in about a week without interfering with Mazza’s normal operations. After sculpting the landscape to improve drainage, digging the detention pond and holes for the StormGate Separator and StormFilter, the engineers installed the precast HDS and StormFilter vaults. Then they placed 30 media-filled filter canisters in the StormFilter vault.
The team placed a 6-ft. by 12-ft. precast StormGate Separator in the ground behind the maintenance and office buildings and near an equipment maintenance pad to catch oil dripping from equipment during service. Treating runoff from the equipment maintenance area, the HDS divides oil and water, as well as some dirt and grit. During a rainstorm, any water flowing through the separator joins catch basin and other site runoff on its way to the detention pond where more pollutants settle out. Overflow from the pond runs into the StormFilter which discharges onto the wetland.
The HDS improves water quality by directing polluted, low-volume runoff into stormwater “cleaning” chambers while allowing heavy rainfall to bypass the chambers. The high-flow bypass in the HDS, along with a speciallyplaced orifice, prevents the flow from heavy downpours from washing any collected pollutants or oil out of the system.
The holding pond helps control the amount of runoff flowing to the StormFilter during the heaviest rainfall. The engineered contours on the site direct the runoff toward the holding pond. When the pond reaches its flood stage, it flows into the StormFilter.
Buried downstream from the pond, an 8-foot by 18-foot precast StormFilter vault holds 30 cartridges with CSF® leaf media that remove pollutants from the pond overflow. Whenever the pond floods, the runoff drains through a buried pipe into the StormFilter system for further cleansing of pollutants. The StormFilter cleans site runoff by passing it through a patented, passive-filtration system to remove pollutants to levels that meet the stringent regulatory requirements NJDEP demands.
The StormFilter cartridges hold CSF leaf media that filters runoff and binds contaminants, especially dirt particles and oil sheen. The media removes pollutants, like sediment, oil and grease, metals, nutrients, organic material, as well as trash and debris before it enters the wetlands. This system and the detention pond address any issues that the Mazza facility has with stormwater pollutants. It’s reliable, easily installed and maintained, and generally recognized as a versatile stormwater best management practice.
The Result
After several years of operation, the StormFilter and HDS continue to provide the company with a simple yet inexpensive method for meeting NJDEP stormwater permit requirements. Recently the company replaced the CSF leaf media in the 30 canisters in the StormFilter. Because the media binds pollutants, it can be either recycled or taken to a landfill with no concern about contaminants entering the water table.
To document that the company meets the state’s stormwater runoff requirements, Mazza hired a qualified testing lab to conduct quarterly quality tests of the runoff discharging into the wetlands. At this point, the company has passed every quarterly sampling test.
Technical Description:
- The Stormwater Management StormFilter®
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