The Greenidge Generation power plant in Torrey no longer burns coal to generate electricity after making the transition to being fueled by natural gas and wood chips in late 2016.

But the remains from years of burning coal to power the generators at the 1930s era plant still fill a man-made mountain just west of the plant.

Lockwood Hills landfill, where tons of coal and biomass ash from the power plant have been piling up to a sizable prominence, is an active site, but not with more ash being hauled in. Workers are removing tons of sediment from a leachate containment area in preparation for improvements required by an agreement with the New York State Department of Environmental Conservation.

Dale Irwin, vice president of Lockwood Hills LLC, and president and CEO of Greenidge Generation, says the improvements were required after state officials determined the unlined leachate pond was the likely source of excess boron, manganese, magnesium, iron, sodium, and sulfate in groundwater nearby.

Leachate is a common term used for the liquid that drains or “leaches” from a landfill. The composition of the leachate is dependent upon what the contents of the landfill are.

Coal ash is the byproduct from the combustion of coal. It can contain contaminants like mercury, cadmium and arsenic — all elements associated with cancer.

Lockwood Hills officials are installing a new geo-membrane liner and a redesigned leachate treatment system as required by a consent agreement with the DEC. The measures, which include separating stormwater from leachate is expected to reduce substances in the groundwater.

The landfill has not received any coal ash since it was acquired by the current owner in 2014, but for many years truckloads of ash were hauled to the top of the landfill, which is lined with a nonporous membrane. The leachate is collected by a series of PVC pipes buried in the encapsulated landfill. Those pipes direct the liquid to a culvert that empties into the containment pond. During this project, however, the leachate is diverted to a group of temporary containers and eventually transported off site for treatment and disposal.

The currently unlined containment pond collects the leachate from inside the landfill, and in the past, stormwater also flowed into the pond. Periodically, leachate is released into a channel that leads to the Keuka Outlet, but not until after testing of the contents indicated levels of various substances are below the limits spelled out in a state discharge permit.

That is the detail that has had some neighbors, Seneca Lake residents, and environmentalists keeping an eye on Greenidge Generation, and Lockwood Hills, both owned by Atlas Holdings.

But Irwin points to the DEC’s approval and oversight of the project, saying the company’s work meets the standards set by the state and federal regulations.

“If Lockwood Hills LLC had not acquired the Lockwood Hills Landfill and agreed to implement the measures of the consent order, these remedial measures may not be occurring at all,” explains Irwin.

The new system already diverts stormwater runoff from the leachate containment pond to another channel and basin. That change alone will reduce the amount of leachate discharged toward the Keuka Outlet, says Irwin.

After all the sediment is removed, a thick geo-membrane will be installed in the bottom and sides of the containment area, which is designed to withstand a 100-year storm.

Then, the leachate will be diverted from the temporary containers back to the containment area. Landfill employees will then monitor the flow of the leachate, and conduct tests for the contaminants, as outlined by the DEC in a State Pollution Discharge Elimination System  (SPDES) permit.

The consent order, which was effective in 2015, includes a deadline of Nov. 1, 2019 for completion. Irwin says at the current pace, the work may be completed by the end of September.

After the project is complete, Lockwood Hills will apply for a modification of its SPDES and 360 (solid waste) permits.

The project, being completed by workers from City Hill Construction under the watchful eyes of an engineering firm and a DEC inspector, is costing the company nearly $1 million, says Irwin.