KEARNY —
If and when Kearny convinces the N.J. Sports & Exposition Authority to vacate the Keegan landfill, the town can consider limited recreational/commercial/industrial uses for the property.
Those scenarios are listed in a Jan. 26 “site review and preliminary future use study” prepared for the town by engineering consultants Hatch Mott MacDonald in consultation with CBRE, a leading global real estate services provider.
First, in an assessment of the environmental health of the site, HMM says concentrations of metals such as nickel, cadmium and chromium dramatically declined since January 2008 “when containment systems were constructed” and the former N.J. Meadowlands Commission took over the operation.
Further evidence that the landfill was being run more efficiently, according to HMM, is found in a significant decline in Biological Oxygen Demand (BOD) – which measures the level of organic material and bacterial activity within the leachate – between April 2010 and October 2014.
That’s all to the good; however, those mounds of wastes – much of it industrial and bulk – that permeate the site will be an obstacle to new infrastructure development, the consultants caution.
And the degree of difficulty will increase if the landfill operator – the NJSEA – further elevates the height of those mounds, from the current 60 feet to a proposed 100 feet.
Adding an additional 40 feet “will cause the upper plateau to decrease in [the] footprint area due to the need to slope to this height. Also, this additional fill will surcharge previously placed waste layers and cause time-dependent settlement,” HMM says.
The consultants say the six acres of flat ground – now occupied by the NJSEA weigh scales and offices – could accommodate “managed open space use, such as sports fields/golf course,” and using the site perimeter road to offer public access to the Kearny Marsh.
Another option suggested by HMM is using the site “for the storage of bulk materials [like] stone or commercial parking” atop the 50-acre plateau.
But even these proposed enterprises would be hard to execute, the consultants say, for this reason: “Due to the large loads imposed by bulk-stockpiling operations, a significant standoff distance from slope top would have to be maintained, which will limit the usable area.” Also, any operational offices “would need good ventilation due to ground gas hazard.”
Any larger commercial structures could be impractical, the consultants say, since, “pile foundations [to support those structures] may have to be in the order of 200 feet deep to reach bedrock and would need to be engineered and constructed to avoid damage while installing through waste layers, and ensure sufficient lateral support …”
As for the presence of sub-surface gas, HMM notes that during a site visit on Nov. 12, 2015, “a moderate odor of hydrogen sulfide was detected.” To address the issue, the consultants say, “It may be necessary” to place an impermeable vapor barrier across the closed landfill to “limit the migration of odors or ground gas” into the air and/or to periodically arrange for “venting” of any trapped ground gas.
In any event, HMM says even after the landfill is shut down, the Kearny Municipal Utilities Authority will still have to arrange for “off-site disposal” of leachate for treatment by the Passaic Valley Sewerage Commission, and that, “It is expected that all development options will share this common requirement.”
One other possible scenario offered by HMM is for “light industrial (i.e.: warehouse)” but the consultants caution that this proposed use “would likely be the most involved of all the available options,” particularly considering health issues and costs.
“Any enclosed structures [atop the plateau] would require significant ventilation due to the ground gas risk, and costly deep foundations or a mat foundation system will need to be proposed to support structures,” HMM says. Or, “Should standard shallow foundations be considered, the foundation system would likely lead to construction and maintenance costs significantly higher than those of a non-landfill site.”
But no “complex land use” at the site should happen overnight because the landfill property needs time to settle, the consultants advise.
“An option should be considered to not attempt any complex land use immediately,” they say. “If the land is left to settle for a number of years and then revisited for development, the issues faced [now] may be significantly reduced. The filling operations since 2009 have been rapid. The fill material and the natural soils beneath will take time to respond to this additional loading.”
Kearny should undertake a “cost-benefit analysis” to “determine when the viability of certain routine construction and development techniques could be feasible,” they say.
Meanwhile, Kearny awaits a response from the NJSEA to the town’s notice to vacate the landfill after its lease runs out on June 30.
