Compatible Materials
It's easiest to install a floating cover along with the liner before water is pumped in for storage, but it is also possible to add a floating cover afterward. In this situation, it's critical to select a floating cover material that is compatible for seaming with the original liner material so you can achieve a robust seal. Using the same material is a good option, but in most cases, you should choose a cover material based more on its features and functions rather than whether it matches the liner material.
Minimize Seams
As you settle on the specific geomembrane for your floating cover, consider the panel sizes available from different suppliers for that particular material. It's vital to minimize the number of seams in the cover because even though they are expensive and prone to leaking when used to seal a pond liner together, they're even more troublesome in covers. Invisible and hard-to-detect gases almost always escape through the cover itself, mainly through seams, and these leaks often go years without detection. The best strategy to avoid the possibility of troublesome leaks is to use a single, seamless sheet of material. Look for a manufacturer like BTL Liners, highly experienced in custom fabrication, to order a cover that will fit the entire pond or tank in a continuous sheet.
Quality Checks
When your cover arrives on-site, take time to make a good visual inspection. Check for obvious holes, scuffs, or any indication of contamination. Review instructions for unfolding the cover material and carry it to the right starting place -- large covers can be pretty heavy and dragging a liner around to reposition after you've started to unfold it presents plenty of opportunities to damage it, even in invisible ways.
Weather
On installation day, make sure the weather is on your side. Rain or snow will make the geomembrane slippery and hard to handle, while a stiff wind could pick it right up before you've finished anchoring.
Dry Ponds
By far, it's easiest to install a floating cover onto a (new) dry pond, especially a large one. In these cases, a pond liner is installed first - from site preparation through anchoring to final testing. Once the liner itself is complete, spread it directly over the liner. For large ponds, be sure to follow the unfolding instructions provided by the supplier. Once the liner is fully extended, examine and test it to ensure it conforms to the specifications in the order - dimensions, fittings, and any specified custom details.
Next, place floats, weights, and fittings on top of the cover sheet. The floats and weights not only help take up slack as the water level changes, but they create channels to direct rainwater to sumps where pumps can remove it. It's important to place these features exactly so the cover can perform as designed. Failure to do so can lead to leaks and other problems and reduce the overall length of service for the cover.
Once the cover has been installed, anchored, and floats and weights applied, it's time to add water. Water is directed between the liner and the cover layers so that they essentially act as a bladder, extending as the volume increases and lifts the cover.
Wet Ponds
If you're adding a floating cover onto an active lagoon, the installation can be more time-consuming and difficult, especially for expansive ponds. First, make sure you have good access to the pond. At least one side (preferably the long one) should be clear of obstacles, so you can use that side to unroll and install features as you go. On the opposite side, you'll need to set up cables and pulleys to float the cover across the pond and secure it into place. Because this can be a complex operation with inherent risks, it's essential to work with an experienced designer and installer to make sure the task proceeds as smoothly as possible.
Maintenance
Even in challenging conditions, with a lot of rain or snowfall, most floating covers made from geomembranes only need attention every six months to once a year. Labor-intensive maintenance chores like cleaning the surface are rarely required more than once a year. Adhering to an appropriate maintenance schedule will keep your floating cover pristine and prevent problematic leaks or incursions.
The most effective maintenance task for keeping a floating cover like new is the annual deep clean. Removing as much dirt, dust, and debris from the surface during this cleaning is the best way to maintain maximum UV resistance and to encourage rapid water flow to the sump pumps. When even small bits of debris like twigs, leaves, and food wrappers build up in the channels of the floating cover, water drains more slowly and starts to weigh down the cover as it accumulates. When debris is carried along by the flow to a pump, it can clog it. Remove debris annually and consider increasing the cleaning intervals if the pond cover seems to be accumulating a lot of dirt or trash before the year is up.
Yearly vent checks are necessary since they're often attractive to birds and rodents looking for places to nest. Even just leaves or other debris falling into the vents can block them causing gas to build up under the cover instead.
Pumps that drain water from the top of the cover deserve attention quarterly to monthly, depending on rainfall and accumulated debris. If piles of leaves and twigs tend to collect in autumn, weekly pump checks may be necessary since clogged pumps can allow a waterlogged cover to fail and sink.
In areas with heavy snowfall, it may be necessary to remove accumulated snow at specific points manually. This task is impossible with hand tools alone, even on small tanks and ponds, so consider an automated clearing system with rakes and rails if you think heavy snowfall will be a recurring issue. If it's a one-time event like a blizzard, crane suspended equipment is available to rent that can carefully clear away large snow loads without damaging the cover. Floating covers may need rails and other heavy-duty supports rather than just foam floats if the snowfall is abundant throughout the winter.
Don't let the idea of occasional maintenance steer you away from tried and tested designs of floating covers. Geomembranes only need annual to monthly maintenance at the most, and generally, these tasks require more inspection time than actual hands-on work. Choosing one of BTL Liners' industry-leading, reliable, high-quality cover materials will further reduce maintenance requirements.
The BTL Advantage
Floating covers are a reliable and time-tested solution for wastewater facilities that need to
- Prevent bank erosion and accompanying turbidity for in-ground lagoons and ponds
- Accommodate changes in water level
- Retain heat to support optimal biological activity
- Manage odors
- Control or eliminate algae
- Optimize TSS settling
- Limit incursion of outside water, protecting against floods and dam collapses
- Collect gas for energy production
The choice of geomembrane floating cover depends on environmental conditions, wastewater composition, and performance priorities. Cover solutions range from basic, with a simple mission and design that includes very few bells and whistles, to complex gas collection mechanisms, temperature management, and structures to support heavy snow loads. In all these cases, the main challenge is finding an economical solution, which requires balancing initial costs with the expenses of ongoing maintenance and the expected longevity of the cover itself.
The expert teams at BTL Liners are proud of their 280+ years of combined industry experience. They're prepared to work with you to design and custom-fabricate covers to fit the geometry of your pond, lagoon, or tank, whether it's a traditional floating configuration or something new and unique meant to address your specific challenges. Their state-of-the-art fabrication facility allows them to produce single sheets of geomembranes up to 150,000 sq feet. Extra-large applications that need to be seamed can be completed in-house, under ideal factory conditions for the most secure, reliable results.
BTL Liners offers a range of floating cover options, from tried-and-true to the most exciting new products on the market. They can help you assess your containment needs and specific challenges and assist you in finding the best balance between budgetary concerns and operational effectiveness. Their 100% reliability guarantee, quick turnaround so you can meet deadlines, and unmatched after-completion support all combine to make your project succeed!
