A floating cover is simply a geomembrane barrier designed to float on the surface of a contained liquid. Two basic types of cover exist; Single Geomembrane covers and Modular Covers.
The Single Geomembrane Cover
This type of cover can take many different forms dependent on the design objective of the cover and the practical circumstances of the installation. A number of technical points need to be addressed prior to commencement of the cover design:
•Chemical compatibility of the contained liquid with the proposed geomembrane cover
•Wet or dry installation, (Liquid in or out of the containment during cover installation)
•Purpose of cover & required service life
•Fluctuation of contained liquid level during service life
•Inlet/Outlet constructions
•Gas collection system
•Surface water collection system
•Service hatches & Monitoring points
•Perimeter geomembrane connection detail
A single geomembrane floating cover uses a combination of attached closed cell foam floats and sand tube ballasts. These elements are used to create drainage sumps that collect and carry storm water to either submersible pumps or gravity drains for water removal into a drainage system. If liquid levels within the reservoir fall, the slack in the liner is given up as the defined folds reduce and then deepen when liquid levels rise again. The floating cover itself is typically fabricated using polypropylene or polyethylene geomembrane with the specific high flexibility folding areas. Floats and ballasts are also encapsulated in geomembrane for maximum longevity. Active gas collection can be achieved using a perforated perimeter extraction pipe beneath the cover under negative pressure.
In general a dry installation of this design begins with the construction of a basal liner. The floating cover geomembrane is constructed directly on top. A wet installation will require the cover to be partially constructed adjacent to the containment area and then very gradually pulled across with construction of additional panels taking place as the pull progresses.
The Modular Geomembrane Cover
The modular cover system consists of individual casings, which are laced together during installation to form a complete cover over the liquid in the containment. Each individual casing is comprised of closed cell insulation sealed between two sheets of durable geomembrane.
Operational Benefits of a Floating Cover
•Cost Efficiency
•Odour Control
•Gas Collection & Management
•Algal Control
•Accelerated Biological Treatment
•High Durability
•Evaporation & Water Ingress Control
•Reduction of Reservoir Chemical Dosing
•Liquid Insulation
•Eliminate airborne Contamination
Industries & Applications
•Mining storage ponds
•Agriculture (Slurry, Lagoons)
•Waste Water/Liquid Treatment
•Utilities (Potable & Waste Water Storage)
•Food Processing
•Brewing
•Chemical Treatment