Covers are widely used in landfill designs in order to control the production of leachate. The first sanitary landfill designs simply called for a thick cap of soil to cover the compacted trash and keep it from blowing away. This did nothing to stop the downward flow of water. Even when these early landfills were lined, the leachate collecting at the bottom quickly rose up and overflowed collection systems with so much water constantly filtering through the layers. This soon led to the specification of impermeable barriers to stop water infiltration from the top down. However, the landfill cell or mound isn’t the only part of the system that requires a cover. Covering a leachate pond may be part of the standard shutdown procedure for the landfill or just a temporary way of dealing with a setback. Here are five situations in which you may want to keep a fitted cover on hand for each leachate pond.
Accelerating a Treatment
Some wastewater treatments break down if exposed to intense sunlight or certain temperatures. Covering the leachate pond temporarily takes a lot of work and coordination but leaving the cover on for a few days to weeks can result in dramatically improved water quality. Activated sludge treatments occasionally call for using a cover to ensure there’s no unintended loss of active bacterial colonies due to temperature fluctuations or direct sunlight. If a temporary treatment cover is needed for just a short period, consider a floating frame to hold it in place without having to permanently alter the pond.
Containing Odors
Odor control requires more than a cover, but it’s the only option in an emergency. If the odor is being accompanied by gases that may not be safe to inhale, covering the pond temporarily puts an immediate stop to the problem. Covers are often used on leachate ponds during certain treatments to keep offensive odors from drifting in certain directions and bothering the closest neighbors to the landfill. In some cases, the leachate pond may need a cover during the whole holding period to meet local air quality requirements. In these cases, the covers must be anchored and vented to ensure they don’t over-inflate and rupture from gas production.
Wildlife Protection
Keeping wildlife and even curious humans out of a leachate pond can seem downright impossible. If nets and fencing aren’t working, a solid cover may be temporarily needed to solve the problem. Breaking the cycle of visiting the pond for just a few weeks can keep wildlife away for months or years; making it a worthwhile investment in the effort of covering and uncovering the surface. A loose or floating cover can work well for this purpose since gas control isn’t generally needed in these cases.
Closing Down the Drained Pond
Once the pond has completed all of its holding and treatment uses and is no longer expected to receive any more leachate from the collection system, it must be properly shut down just like the landfill cells themselves. Drained ponds become large sinkholes that can dangerous for animals that wander in and become trapped by the sloped sides. With a little appropriate filling and a final cover, the pond will become a natural part of the landscape again instead. Drained ponds almost always include some semi-solid waste sludge left at the bottom, making it essential to cover and cap them just like other parts of the landfill. Make sure to use an impermeable cover so water doesn’t gather in the lined basin below the surface and slowly rise up to lift contaminants to the surface.
Temporary Cover
Finally, it may be possible to protect a leachate pond from overflowing or taking storm damage by the judicious application of a durable temporary cover. However, you’ll need a complete pump system to pair with the cover to ensure it doesn’t just end up bogged down with water as well. Even the cover will only be deployed for a few hours at a time in case of storm damage, make sure it’s already set up and easy to use before any emergencies occur.
BTL Liners doesn’t just supply the lining materials you need for building leachate ponds and the collection systems to supply them. We also have all the cover materials you need for landfill capping and covering leachate ponds. Check out our selection of RPE products today to find what you need for your project.
