Current weather

  • Overcast
  • 61°
    Overcast
  • Comment

Borough landfill fluids in focus

Estimated $3.4M facility likely among year's top capital projects

Posted: December 30, 2012 - 9:04pm

One of the items Kenai Peninsula Borough officials hope to have state lawmakers include in the state’s capital budget is infrastructure needed to create a long term solution for treatment and disposal of landfill fluids, also known as leachate.

In its draft capital funding priorities list to be considered by the Kenai Peninsula Borough Assembly at its Jan. 8 meeting, borough administration requested $3.4 million for a leachate thermal evaporation unit. The unit would be the least expensive and most effective process to allow the borough solid waste department to deal with the leachate that can no longer be treated in the way it has been for the last several years.

Jack Maryott, borough solid waste director, said the borough has had to treat leachate since changing environmental regulations required landfills to install liners beneath waste masses. As a result of the liner at the Central Peninsula Landfill, precipitation percolates through the garbage, is collected at the bottom, pumped out and managed. It is not considered a hazardous material, he said.

A permit the borough previously obtained allows landfill managers to recirculate that leachate back into the waste, which has numerous benefits, Maryott said. Although the landfill, at any given time, may have millions of gallons of leachate circulating through it, spikes in leachate that can’t be handled on site need to be disposed of properly. Spikes are caused by heavy rainfall, large snowfalls, spring breakup and are also influenced by the amount of waste contained in the cell.

Maryott said the borough previously sent that excess leachate to Kenai’s wastewater treatment facility for several years, but the city recently notified the borough that option was no longer on the table.

Kenai City Manager Rick Koch said the city’s treatment facility was being adversely affected by the borough’s leachate.

“The composition of that leachate is different than it used to be,” he said. “I don’t know what it is, but we immediately see the effect in the plant. It’s a significant effect. It took us almost three months to recover from the last time we took it.”

Koch said the city would have liked to help the borough.

“They got a problem and unfortunately with these sorts of things there are no cheap solutions to any of this stuff,” he said.

A borough-commissioned leachate management study generated five options to deal with the liquids, including the evaporation unit, pre-treatment and shipment to Kenai’s treatment plant, pre-treatment and then discharge into an engineered wetland, full treatment and discharge into the Kenai River or hauling it to the waste water utility in Anchorage.

While the evaporation unit was determined to be the most logical, the borough is also working on a temporary discharge permit with the municipality of Anchorage to have a backup option available, Maryott said.

Maryott said it is common practice in the state for landfill leachate to be treated at municipal wastewater treatment plants. The borough didn’t think the leachate would upset Kenai treatment facilities when the option was first examined, but knew it needed a long-term solution, Maryott said. The borough shipped 700,000 gallons of leachate to the Kenai facility in 2008, but that number dropped to 200,000 in 2010 and 98,000 in 2012, he said.

“When you have these big surges, you want to get rid of the excess and that’s what’s been going to the city of Kenai,” he said. “The amount that we are managing versus the amount that we’ve actually shipped off is not even close.”

One of the “big benefits” of being able to recirculate the leachate through the waste mass is that the process aides in stabilizing the waste quicker, Maryott said.

“By reinjecting the leachate back into the waste mass, what that does is the waste breaks down and decomposes faster, you end up getting more air space and one of the primary benefits in theory is you stabilize the waste mass sooner,” he said.

Once the waste settles and adds “air space” the borough can come back into that cell and add more waste.

However, each time the leachate circulates through the landfill’s waste mass, less and less is absorbed. Eventually the cell will reach “field capacity,” and will no longer hold any more fluids.

The borough, Maryott said, has a sizeable effort to mitigate leachate production, mainly by covering portions of the landfill not in use with plastic. Precipitation that doesn’t mingle with the garbage can be treated as storm water runoff, he said.

Another benefit of the leachate circulation process has to do with the gas normally produced at a landfill. Regular processes that generate gas through the decomposition of waste are expedited through leachate recirculation because it increases the speed at which waste breaks down.

“You don’t generate an aggregate more total gas, it just comes faster,” Maryott said.

Eventually, enough gas is produced at the landfill that it needs to be managed, which is where the thermal evaporation unit comes back into play, he said.

While the thermal evaporator is the cheapest option for leachate, the unit has a high energy cost.

If installed, the unit would require natural gas from the market to operate initially. But Maryott hopes gas the landfill produces will be sufficient to offset that fuel cost in the future.

The evaporation unit, he said, runs at a low temperature and releases only water vapor into the air leaving trace amounts of leachate residuals that are then put back in the landfill. Eventually, as each of the landfill’s cells are closed and capped they will be drained of their excess leachate.

The unit will also allow the borough to not get caught up in any changing environmental regulations tied to Cook Inlet, as that is where most municipal water ends up after treatment. Additionally, the borough will not have to adjust how they handle the leachate based on how its composition may change in the future. Other treatment methods might require process adjustments to match the leachate’s makeup.

“It will be strictly under our management,” Maryott said. “Total control with no outside influences.”

Brian Smith can be reached at brian.smith@peninsulaclarion.com.

  • Comment

Comments (6) Add comment
ADVISORY: Users are solely responsible for opinions they post here and for following agreed-upon rules of civility. Posts and comments do not reflect the views of this site. Posts and comments are automatically checked for inappropriate language, but readers might find some comments offensive or inaccurate. If you believe a comment violates our rules, click the "Flag as offensive" link below the comment.
robert white
378
Points
robert white 12/31/12 - 10:11 am
0
0
leachate

Take it out of the ground and put it in the air so we can breathe it. Wonder why this is one of the hot spots in the country for colitis?

Sam Von Pufendorf
1088
Points
Sam Von Pufendorf 01/02/13 - 09:30 am
0
0
@ Robert White

Evaporation of the leachate water is not uncommon and is used in giant landfills across the country. Since decomposing waste naturally produces methane gas, some landfills are tapped for methane use.
From the article: "The evaporation unit, he said, runs at a low temperature and releases only water vapor into the air leaving trace amounts of leachate residuals that are then put back in the landfill." The gas portion of the leachate would eventually be used in the evaporator as stated; "If installed, the unit would require natural gas from the market to operate initially. But Maryott hopes gas the landfill produces will be sufficient to offset that fuel cost in the future."
If implemented in phases, an evaporation unit can actually contribute to energy needs.
Robert, here are a couple of sources to investigate concerning waste management, leachate treatment and Landfill Gas (LFG):

http://www.heatxfer.com/files/LandfillGas.pdf

http://www.epa.gov/lmop/

motely
238
Points
motely 01/02/13 - 11:19 am
0
0
RE : Sam Von

Myron has it all figured out ! he wanted to build his dream development on his 51 acres that he acquired, That's a little funny because I cannot seem to find it anywhere on the borough parcel viewer or in the proximity of the alleged dump site, although I was able to find a 52 acre tract and its located right next to the MI SWACO building, which by the way, would be a company that does something with the drilling mud's, are they up to par with everything I wonder ? what about the water in McGahan subdivision is that safe ? water wells being punched on 1/4 acre lots and smaller, with mind you
existing sewer ! how is that safe ? Not sure but having water near sewer is not good.
Anything for attention and a free ride is really whats happening
Always the VICTIM,
yah know what I mean ?

motely
238
Points
motely 01/02/13 - 11:24 am
0
0
Re : Sam Von

I apologize,
Wrong story, really concerning though !

Seafarer
1147
Points
Seafarer 01/02/13 - 05:30 pm
0
0
Free Heat Source

ANC is using the heat generated at it's landfill to heat a whole bunch of muni bldgs. Why can't we?

Sam Von Pufendorf
1088
Points
Sam Von Pufendorf 01/02/13 - 06:19 pm
0
0
Landfill size and capacity

If you look at the Capacity of the Anchorage Landfill, its power generating potential is considerably larger than that of the Peninsula. Anchorage landfill receives about 360 thousand tons of waste a year and Central Peninsula receives 1/6 that amount or 60 thousand tons annually. The energy generated by the landfill is the equivalent to the BTU needed to heat several Anchorage municipal buildings or a power equivalent of 2.5 - 3 megawatts of electricity.
Our landfill can't generate near that amount of energy. However, it may generate enough energy to supply its own gas to operate the evaporation unit and possibly a bit more.

http://www.akenergyauthority.org/PDF%20files/Brochure%20for%20REAP.pdf

http://www.borough.kenai.ak.us/swd-waste/swd-locations/158-swd-centralla...

Back to Top

Spotted

Please Note: You may have disabled JavaScript and/or CSS. Although this news content will be accessible, certain functionality is unavailable.

Skip to News

« back

next »

  • title http://spotted.peninsulaclarion.com/galleries/321268/ http://spotted.peninsulaclarion.com/galleries/321253/ http://spotted.peninsulaclarion.com/galleries/321248/
  • title http://spotted.peninsulaclarion.com/galleries/321243/ http://spotted.peninsulaclarion.com/galleries/321208/ http://spotted.peninsulaclarion.com/galleries/320593/
  • title http://spotted.peninsulaclarion.com/galleries/321173/ http://spotted.peninsulaclarion.com/galleries/321163/
My Gallery

CONTACT US

  • 150 Trading Bay Rd, Kenai, AK 99611
  • Switchboard: 907-283-7551
  • Circulation and Delivery: 907-283-3584
  • Newsroom Fax: 907-283-3299
  • Business Fax: 907-283-3299
  • Accounts Receivable: 907-335-1257
  • View the Staff Directory
  • or Send feedback

ADVERTISING

SUBSCRIBER SERVICES

SOCIAL NETWORKING

MORRIS ALASKA NEWS