Landfill Sustainability: Pulling the Plug on Leachate

by Fred Doran on January 28, 2015

LEACHATE3Leachate, the liquid created when water passes through solid waste, poses a challenge for landfill owners. Potentially harmful to the environment and to people, leachate can contain compounds such as arsenic or vinyl chloride. This wastewater creates the need for solutions that protect communities and fall within budgets set aside for waste disposal operations. Here are a number of factors that need to be considered when deciding how to efficiently manage leachate at a landfill.

Prevention Better Than Cure

Start by implementing strategies that prevent disposal of contaminants at landfills. Initiatives that encourage households and businesses to dispose of waste properly can reduce the buildup of harmful substances in landfills. Household items like pharmaceuticals, paint, electronics, batteries and appliances can all be disposed of in ways that eliminate leachate problems.

From a landfill owner’s perspective, a waste acceptance and inspection programs can also minimize the amount of hazardous material that enters the landfill. Industrial waste generators, for example, provide source and chemical information to verify whether a material is hazardous or not.

Pretreatment: A Careful Consideration

When waste begins to degrade, natural biological and chemical processes are at work. The leachate often contains harmful metals and volatile organic compounds (VOCs); it also typically has high biochemical oxygen demand (BOD) and chemical oxygen demand (COD).

Chemicals often must be removed from wastewater through pretreatment to meet publicly owned treatment works (POTW) standards. Biological reactors, surface ponds, constructed wetlands, physical or chemical plants and reverse osmosis are some of the ways to reduce chemical content. At the Crow Wing County Landfill in Brainerd, Minn., for example, leachate is treated in four ponds that collectively form a reduction system featuring primary treatment, secondary treatment and long-term storage.

Nature’s Course: Land Application

Leachate that has been collected and pretreated can be absorbed by the land itself as a means of disposal. Through a process called phytoremediation, trees such as willows and hybrid poplars, as well as some grasses, can absorb certain contaminants like metals, nitrogen and VOCs. Similarly, many surface soils can absorb unwanted leachate. These land application solutions have demonstrated positive results in Maryland, Oregon and elsewhere.

Recirculation: A Fluid Solution

Using a series of horizontal pipe manifolds or a spray application, treated leachate can be circulated back into landfill waste to improve conditions. This offers these benefits:

Faster Decay. Moisture speeds the breakdown of organic materials. With proper leverage, moisture levels can double or triple the rate of landfill waste decay. If regulations allow, surface water, wastewater, sludge and biosolids can create a bioreactor that promotes microbial activity in the waste, improving leachate quality and reducing contamination as landfills reach capacity.

Quicker Waste Stabilization. The additional water weight speeds the rate at which landfill waste compacts, extending the site’s life. For example, if a typical cubic yard of waste at a landfill contains 1,000 pounds of garbage, recirculating water through the waste can expand that to as much as 2,000 pounds per cubic yard, doubling the useful life of a site.

Alternative Gas Production. Additional moisture within landfill waste promotes development of methane gas. Landfill owners can implement an energy recovery project by collecting and using this gas. For example, at the Sioux Falls Landfill near Sioux Falls, S.D., recirculating leachate contributes to more than 2,000 cubic feet per minute of landfill gas, which is then used as an alternative to natural gas, increasing landfill revenue.

Evaporation: A Disappearing Act

In drier climates, evaporation through large surface storage ponds is a common solution for reducing leachate. Other evaporative methods that have recently been employed in northern climates include impact sprayers or commercial misters on the working face or intermediate covers of landfills to evaporate leachate. Similarly, installing pump systems in a storage pond to spray leachate over the water surface is common in colder climates. When the leachate is sprayed onto the black plastic liner, the water evaporates, reducing the leachate volume.

Constructed Wetlands

A lined, submerged wetland can provide leachate treatment by using its natural plant and soil processes to break down contamination. Aerated zones promote aerobic and anaerobic treatment, removing metals and organics.Discharging treated leachate into seepage wetlands allows evaporation to occur before the liquid percolates into the subsurface.

Going the Distance with Hauling

Of course, you can also minimize leachate by hauling it away treatment and disposal. Hauling can be an operational challenge and a large expense, both monetarily and environmentally. For example, in 2013, Sioux Falls hauled 7.8 million gallons of leachate to its POTW. The 25-mile round trips resulted in more than 90,000 pounds of carbon dioxide emissions. In an effort to reduce the effects of hauling, the city is considering phytoremediation as an alternative.

What do you think of these solutions for reducing leachate in landfills? Which methods do you think are the most effective? Have you come across any other methods employed by landfill owners to reduce hazardous chemicals in wastewater? We’d like you to share your opinions on this ongoing issue.

Fred Doran is a department manager in the Environmental Group of Burns & McDonnell, where he leads solid waste projects with particular experience in leachate and landfill gas management systems. He is a registered professional engineer in five states and is a member of the Landfill and Landfill Gas Divisions of the Solid Waste Association of North America (SWANA).

A version of this article original appeared in Waste360 – Landfill Leachate: Wringing Waste from a Common Solution

Photo Credit: Waste360

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high voltage 01The state of the power industry is changing rapidly, and it can be difficult to keep up with everything. But it’s more important than ever to understand the biggest issues affecting the industry, which is why I’m excited about the 25th annual DistribuTECH conference coming up in San Diego Feb. 3-5.

DistribuTECH is the largest transmission and distribution conference in the world; it connects utility industry leaders and technology enthusiasts worldwide. It’s the place to network with other utility professionals and share knowledge, expertise and ideas for solutions to the industry’s power delivery challenges.

The conference sessions are always are always a favorite of mine, as it’s a great opportunity to gain a better understanding of issues affecting the power industry and to share our knowledge on the topic. My team and I are excited to be delivering key presentations as part of five tracks during the conference:

Smart Grid Operations Solutions Track

Paul Pansing and Andrew Wedekind will present “Devastation to Restoration: 14-Foot Wave Damage Leads to Improved Reliability” at the “Strategies for Improving Distribution Resiliency” session at 1 p.m. on Tuesday, Feb. 3.

Paul and Andrew will join Lauren Thomas from PSE&G for a presentation on the importance of preparing for major storms, staging for rapid restoration after storms and improving communications to customers during restoration, which are all part of improving the resiliency of the distribution system.

Demand Response Track

Meghan Calabro is partnering with Ed Hedges and Mark Hopkins from Kansas City Power & Light and Andrew Dicker from The Structure Group to present “KCP&L’s Smart Grid Demonstration Project’s Hierarchical Demand Response Management Implementation Leveraging Multiple DR Messaging Standards” as part of the “Demand Response Communications Innovations” event at 1 p.m. on Tuesday, Feb. 3.

Meghan’s session will include discussions on innovations in demand response communications that leverage national standards, including OpenADR and Zigbee, plus standard-setting activities.

Smart Distribution Management Track

Meaghan Calabro is also part of the “KCP&L Smart Grid Demonstration Project: Gaps Identified in Current Smart Distribution Technologies Requiring Evolution to Support Emerging Functionality.” She joins Ed Hedges and Steve Goeckeler from KCP&L and Satyaveer from The Structure Group as part of the “AMI, OMS and IT panel” on Tuesday, Feb. 3 at 3:00 p.m.

In this presentation, they’ll cover how application integration is imperative for successful smart grid implementation and other IT integration challenges.

Renewables, Transmission and Policy Track

Linda Lynch will present “FERC-approved Definition of BES and its Impact to Your Organization” as part of the “Key Grid Policy Evolution for Grid Reliability” event at 3 p.m. on Tuesday, Feb. 3.

In Linda’s session, she’ll cover the current NERC Bulk Electric System (BES) Core Definition, which provides a continent-wide uniform process for identifying BES assets that are subject to the NERC Reliability Standards requirements. She’ll also discuss the criteria for inclusion or exclusion and the recommended steps for the self-determination process.

Substation Integration and Automation Track

Mitchell Lowery will present “Resolving the Challenges of Multiple Vendor 61850 Implementations” in the session “Addressing IEC 61850 Interoperability – Multivendor Challenges, Deployment Lessons and Standards-based Solutions” at 9:30 a.m. on Wednesday, Feb. 4.

During Mitchell’s session, he and Eric Schroeder from Cross Texas Transmission will discuss interoperability problems utilities face when using IEC 61850 within substation environments and the approach utilities and international organizations take to deal with these issues.

Also part of this track, Meghan Calabro returns for her second presentation with Mark Hopkins and Ed Hedges from Kansas City Power & Light and Andrew Dicker from The Structure Group for “KCP&L’s Experiences with IEC 61850 GOOSE Messaging in a Smart Distribution Substation Implementation” as part of the “IEC 61850 Success Stories and Other Lessons from the Front Lines” session at 8:30 a.m. on Thursday, Feb. 5.

Their presentation will focus on how a growing number of North American utilities, their consultants and automation partners have been testing and piloting IEC 61850 and have also implemented projects including retrofits of large existing substations.

Customer Strategies and Technologies Track

And finally, I’m excited to moderate a panel discussion, “Transactive Energy: A Customer Perspective,”, at 9:30 a.m. on Wednesday, Feb. 4.

I’ll oversee the discussion with Jeff Gooding, Southern California Edison; Thomas Bialek, San Diego Gas & Electric; and Tony Tewelis, Arizona Public Service, on how transactive energy — the convergence of the legacy T&D system with DER, DR and storage — affects our existing systems from a planning, design and operational perspective, and where the opportunities are for customer engagement. The session will also address what new products and services can be developed for the process and what challenges states have encountered when implementing these transactive energy systems.

This is only a small sampling of what’s in store for this year’s DistribuTECH event. You can view complete details and a full schedule of events here. You can also keep up with the action following @DistribuTECH on Twitter and using hashtag #DTECH2015! And if you’re on the exhibit floor, be sure to stop by booth #4114 and say hi.

Mike Beehler is a vice president in Burns & McDonnell’s Transmission & Distribution Group. He has extensive experience leading large-scale transmission projects throughout the U.S. Before joining Burns & McDonnell, he spent 14 years with an investor-owned electric utility. You can find and connect with Mike on LinkedIn.

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Greater Springfield Reliability Project Powers the Northeast, Racks Up Awards

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Following a $678 million investment by Northeast Utilities, a once overworked section of the electric grid serving millions of New England residents is officially fully charged and fully committed to providing power to the surrounding community. The Greater Springfield Reliability Project (GSRP) was the first of four major transmission upgrades included in the extensive New […]

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