ROCKPORT — Work continues in earnest this week at the Mid-Coast Solid Waste Corporation transfer facility on Union Street in Rockport, work that involves installing a subsurface dam between the water-filled northern end of Jacobs Quarry and the waste-filled southern end.

When complete, the dam will cut the flow of water off between the two, allowing for an anticipated drop in the facility's leachate pumping and treatment costs by between 35 and 40 percent per year. According to MCSWC, that savings could allow the work investment to pay for itself within 15 years.

Transfer Station Manager Jim Guerra said Wednesday that thus far, "everything is where we thought it would be, where we want it to be."

Sargent Corporation is the contractor hired for the job, and they broke ground the last week in October. Guerra said the cost of the work is not to exceed $630,000.

"We are currently within spinning distance of having all the sheet in place," said Guerra. "And the idea is to drive two rows of sheet pile, 16-feet apart, at the narrowest part of the gut that joins the two quarries."

Sheet piling is an earth retention and excavation support technique that retains soil, using steel sheet sections with interlocking edges.
Guerra said they will be creating a box 16-feet-wide and across, with two sides being contained by bedrock and two sides by the sheet piling.

"Then, we will replace that material between with dense concrete, and ultimately build a dam-style structure on top of that," said Guerra.

He said that of the material thus far that has been dug up and extracted from the deep part of the gut, everything appears to have been burned and then bulldozed in.

"So it's no wonder we are getting water coming through [between the north and south quarries], as it's porous and the water flows right through it," said Guerra.

And that's where the problem, and expense, lies for the transfer station, as that water ends up as leachate that must be pumped and treated by Camden's Wastewater Treatment Plant. Although MCSWC and the four communities that make it up are committed to pump some amount of leachate from within the waste-filled quarry to the treatment plant forever, the hope is that the work to separate the two quarries will reduce the pumping and treatment costs by as much as 40 percent.

Guerra said they plan to dig down further than have so far, to 58-feet below the surface, and with the success and information they have gathered thus far, he said the cost savings could be even greater.

"It's no wonder the first two attempts we made to stop the water flow across the cut did not stand a chance, given what we now know about the materials that are down there, and how porous they are," said Guerra. "This knowledge is only available because we are already 35-feet below the surface, deeper than before. We have a big hole here and we plan to go deeper still. The potential is there now for a bigger cost savings."

The transfer station alerted residents and commercial users of the facility last month about the impending construction project, and the need to maintain safety by keeping traffic going one-way only. They also asked residents to minimize trips, or make them during the week, when the transfer station is less congested, and to drive with care and follow instructions provided by staff and crews on site.

Again, Guerra said this part of the work has gone well.

"Last Saturday I spent the entire day directing traffic through the pinch spot, and I am pleased to report that residents are doing a very good job, those that deliver their own trash, they are doing a great job recycling. Only a few came through and went directly to the trash drop-off without stopping to recycle anything," said Guerra. Going forward, our focus will be on pushing more recycling."

He said that the project, when complete and successful, will provide a "sound closure to the landfill system.

"In other words, you can't close this place without closure of this issue as well," said Guerra.

Guerra said that as long as the weather holds and they don't hit any major snags while digging, like running into ledge, Sargent anticipates finishing the work on time at the end of November.

Reach Editorial Director Holly S. Edwards at hollyedwards@penbaypilot.com and 207-706-6655.