Flexible membrane caps

This section describes the elements in a closure or cap system of a completed landfill, including flexible membrane caps (FMCs), SWCR systems, gas control layers, biotic barriers, and vegetative top covers. It also discusses infiltration, erosion control, and long-term aesthetic concerns associated with securing a completed landfill. 

The third part, called the surface water collection and removal (SWCR) system, lies above the waste system in a cap or closure above the closed facility. Its purpose is to redirect surface water coming through the cover soil from the flexible membrane in the cap to the outside perimeter of the system. The location of all three parts of the liquid management system is illustrated in Figure 26.21. 

As we saw in Fig. 11.4, thin flexible membranes of micrometersized capillaries can be significantly deformed due to the surface tension forces of the liquid inside. The figure shows silicon oxide channels of several micrometer width and about 80 nm height. These channels are capped by a thin, flexible silicon oxide-silicon... 

TPEs are used as gas or liquid barriers in many applications caps, bottles, films, separators, etc., where they can be responsible for the barrier effect or for the separation. Often they represent only substrates coated with an active component but imparting, for instance, the mechanical properties the active layer can be plasma-deposited [170]. Some very few studies analyze the influence of the TPE structure on the behavior of the membranes Ziegel [171] showed that the rigid and flexible domains of a thermoplastic polyurethane elastomer behave in different ways in gas transport. 

Membrane cartridge filters are extremely flexible and high in tensile strength. The cartridge construction is based on a multi-layer combination of filter media in pleated format. Those polymers that have been used extensively as filtration media in coarser grades are now widely used as membrane filters. A typical format has a cartridge fabricated from a pleated filter pack, which contains a very fine polyolefin fibre prefilter layer, two nylon membranes of the same pore (0.2 pm) size, and a downstream polypropylene support. The layers of nylon microporous membrane and polypropylene prefilter are pleated together and snpported by an inner snpport core. The end-caps and core are melt sealed in polypropylene. 

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