Turbidity Barriers, Baffle Curtains
Permathene Ltd specialises in custom built silt and debris containment booms, as well as turbidity floating barriers and pond baffles. Baffles are commonly used to improve the hydraulic and treatment efficiency of ponds. There are several ways in which baffles can be built. They can be constructed from concrete, rocks or earth as a part of the original design. However this can limit opportunity to control the process, for which the pond has been designed.
Permathene manufactures baffles in a strong impermeable membrane (PVC, LLDPE, HDPE or polypropylene), or a combination of impermeable membrane, slit film or monofilament geotextile and marine grade flotation devices. Standard manufacture in sizes from 1 m to 20 m curtain depth and standard boom lengths from 3 m to 15 m (other sizes available upon request). Flotation is by closed cell polyethylene logs. These logs are completely enclosed within sleeves by means of fusion welding to prevent any water from entering. All fittings made from metal are corrosion resistant galvanised steel, stainless steel, brass or aluminium.
Applications include waste water treatment, stormwater retention ponds, sediment control, enclosement and separation, oil and spill containment systems, mining and agriculture.
Flexible removable Permathene baffles have many advantages, such as cost effectiveness, flexibility to allow the possibility of changing the baffles position in the pond, as well as removal for maintenance, etc.
Permathene can provide engineers and designers with variety of options, including heights, length and material of fabrication. Standard impermeable baffle, or partition, consists of a surface floating element, supported on the surface by tensioning wire rope (galvanised steel or plastic), flexible sheeting and ballast, or anchor, chain at the bottom.
Module:
As a “module” Permathene Limited understands a single composed baffle, the number of modules, or baffles for each application can be different, but in general many experts recommend a minimum of 2 baffles and a maximum of 4 with even baffle spacing across the pond as the most effective method.
Units:
Baffles with module sizes longer than 25 m long will be fabricated from separate units, anywhere between 5 m and 25 m. Units will be interconnected by frequent bolting through eyelets installed in double liner hem, reinforced with flat sealed galvanised steel bar.
Sections of the anchor chain will be interconnected with D-shackles.
If baffles have to be constructed from multi-units, the units length will be calculated to link with total baffle length.
Slopes:
Permathene will manufacture baffles with specified slope, typically 1:1, 1:2, 1:3 or a combination. Slope part of the baffle will be reinforced with sealed flat galvanised steel bar.
The skirt depth of the baffle is the Permathene specified geosynthetic liner vertically below the floating element’s hem. Depending upon application, baffles can be fabricated from 0.5 mm, 0.75 mm or 1.0 mm Permaliner (Flexible Polypropylene) or HDPE, using both fusion and extrusion welding.
If requested, a special reinforced HDPE strip with brass eyelets can be manufactured for attachment of the module to the pond’s wall. Aluminium bars with neoprene gaskets and dynabolts to be used for connection.
Openings:
Openings are holes in baffle’s skirt, designed for various purposes. Woven Geotextiles can be used for sediment control and filtration baffles, interconnected with main liner body by method as defined by Permathene. The size and position of geotextile completed or non-covered openings on the baffle’s skirt are determined by designer. Permathene will provide engineers with flow rate data for different types of Syntex woven, nonwoven and monofilament geotextiles.
Anchoring:
Both, supportive wire rope and anchor chain hems will be reinforced with LDPE or PVC pipe as determined for the particular specified size. Permathene Limited would not recommend utilising external concrete or steel weights attached to the anchor line of the baffle for ballast. This may create local high stress concentration on the liners lower line. Where bottom anchoring is required, we can reinforce the connection point with stainless steel plates to minimise local stress and plastic wire rope to eliminate corrosion issues.
Permathene Limited can supply a complete anchoring system, with custom made galvanised steel or stainless steel plates with through bolts, turn buckles, and tensioners.
The Baffles described above are standard. Permathene can custom design floating and tensioned baffles to assist in solving of specific engineering tasks.
Maintenance:
Permathene Limited can provide a support guarantee which offers replacement or repair for a period of five years for baffle curtains manufactured entirely by Permathene and supplied in accordance with approved installations and designs.
Delivery:
The floating pond baffles shall be delivered to the job site by the manufacturer on four-way entry pallets acceptable for motor freight transport. Containers shall be marked with the modules and units numbers.
Field Service:
Permathene Limited can provide the services of a qualified field technician to supervise the installation and repair of the baffle if required by the customer.
Material Types:
Vinyl Coated Polyester or Nylon (PVC):
Provide silt containment in a tough reinforced material. These barriers are suitable for a wide range of environments including open water operations such as dredge and drag line. PVC type barriers have very high strength but have a limited UV life and are not recommended for permanent installations beyond 5 years.
Permaliner Polypropylene:
Barriers are manufactured in flexible Permaliner polypropylene with or without a slit film or monofilament geotextile curtain or windows. We custom manufacture Turbidity Barriers, Sedimentation Control Baffles, Separation Curtains. These are commonly used in waste treatment ponds as separation barriers and are manufactured to fit the contour of the pond. Typically manufactured in 0.75 mm - 1.0 mm Permaliner flexible polypropylene resists a wide range of chemicals with excellent UV resistance (can last 20 years). See sidebar for link.
HDPE, LLDPE:
Certain installations require an extremely resistant material. Barriers which do not need to be highly flexible yet need chemical resistance and high resistance to mechanical damage are often made in these materials. See sidebar for links.
Documents:
Technical Pages (pdf): (includes design and project info)
