The Middlesex County Landfill opened on February 5, 1992 after six-months of intensive construction preparing the initial cells for solid waste. The Landfill initially had three cells, each with its own double-liner system, leachate collection and secondary detection system. The Landfill features a state-of-the-art double liner system, which has a maximum permeability of 1.0 x 10-7 cm/sec (meaning 1 inch of water may seep through every 30 years). It also consists of a 60 ml high-density polyethylene liner, 18 inches of filter sand, and 80 ml high-density polyethylene liner, drainage net, a filter fabric and 18 more inches of filter sand. Additional cells were constructed bringing the total number to nine cells by 2010.
The Landfill also has a leak detection system between the liners and a leachate collection system on top of the 80 ml liner that collects rainwater permeating the Landfill or liquid from any bio-degradation taking place in the Landfill. This leachate is pumped into the MCUA trunk line and transported to the Wastewater Treatment Plant in Sayreville.
In addition, systems are in place to collect methane gas formed by biodegradation in the Landfill, so this greenhouse gas can be collected before re-entering the atmosphere and put to beneficial use. The gas will be collected using a combination of vertical and horizontal gas wells spaced approximately every 200 feet across the surface of the Landfill. The gas is then transmitted through a processing skid where it is recycled as fuel for the electrical power generation facility.
The area where waste is placed is called the “workface”. As the solid waste is tipped it is compacted to conserve space. At the end of each day, approximately six inches of cover material is placed and compacted on top and nine-inches on side slopes of the solid waste. If the area is not used again for 24 hours, a twelve-inch additional layer of cover material is added. In addition to soil, recycled products are used for daily intermediate cover.
Each person in Middlesex County generates approximately 11 lbs. of waste each day, which amounts to 4000 lbs. per person, per year. Based on averages during calendar year 2010, every day approximately 200 trucks transport waste to the Landfill. This equates to approximately 500,000 tons of solid waste every year. The trucks are weighed at the scale facility as they enter the Landfill for revenue and waste tracking purposes. Only trucks registered with the NJDEP and carrying solid waste collected in Middlesex County ‘s 25 towns are permitted to dispose solid waste at Middlesex County Landfill.
Based on Middlesex County ‘s population, recycling efforts, and market trends, it is anticipated that the Middlesex County Landfill will be able to accept 20 million cubic yards of solid waste for disposal, operating through 2024. The Middlesex County Landfill will cover over 300 acres of land and reach its permitted maximum height of 165 feet above sea level. To prevent degradation of the surrounding environment, protective barriers such as landfill liners, layers of cover material, and a protective cap are implemented to seal-off the inactive cells. These barriers naturally control potential releases from the landfill. Once the Landfill is capped the MCUA will continue monitoring the site for 30 years.