A first in France and Europe. Weir
Minerals, specialist in pumps for loaded liquids, has just
installed a pumping system designed to meet the worrying problem of
beach erosion on the Aquitaine coast.
An environmental and ecological
problem
Since the early 1980s, the town of Capbreton
has had to deal with a double problem: sand removal from the
Boucarot channel and the return of sand to its beaches. To address
this phenomenon, 4,000 lorries loaded with sand had to cross the
resort’s beaches every year in order to transport sand from the
north beach to the beaches to the south. This costly solution was
simultaneously non-ecological, restrictive and imperfect: pollution
caused by transit of lorries on roads, difficulty in accessing the
beaches and an insufficient volume of sand carried.
Intervention by Weir
Minerals
The town of Capbreton therefore decided to
seek out new solutions and, in August 2007, contacted the company
Eurotechnologie, which specialises in hydro-ejectors. This company
asked Weir Minerals to carry out a feasibility study on the
transfer of sand from point A to point B.
It was a major challenge: sand (a dry element)
had to be conveyed, whereas Weir Minerals pumps are generally used
in quarries where a mixture of water and sand is carried. The Weir
Minerals study ordered by SOGREAH resulted in a proposal that
artificially re-establishes the movement of sediments.
An unusual technical
solution
The chosen solution is a bypass, a hydraulic
system for transferring sand, which operates with a hydro-ejector
(see attached diagram). The sand is first fluidized before being
transported with water by the Weir Minerals pumps which then serves
the various outflows (corresponding to the beaches).
The system comprises the following
elements:
• A hydro-ejector used to
extract sand from the North beach,
• A pump for taking up clear
water from the Boucarot channel and linked to the
hydro-ejector,
• Relay pumps placed further
back to ensure sufficient hydraulic power to supply the south
beaches,
• Outlet pipes placed across
the Boucarot,
• Rigid piping placed under
the Capbreton seafront with regularly spaced outflows, the
insulation of which is provided by Isogate valves, specially
designed for abrasive products,
• Flexible piping that can
be connected to the outflow openings.
A few figures to illustrate this
performance…
• The system is capable of
transferring an average of 180 m3/h of sand,
corresponding to 12 to 15 weeks’ operation.
• One cubic metre extracted
by this system costs 2.9 euros, before tax, compared with 5 euros
for a cubic metre transported by lorry,
• The investment made by the
town of Capbreton amounts to 4.5 million euros.
Weir Minerals France
WEIR MINERALS France belongs to the WEIR plc
group, based in Glasgow (Scotland), created in 1871 and listed on
the London Stock Exchange since 1982. The Group currently works all
over the world.
WEIR MINERALS France is established close to Lyon in Bron and
has a plant in Castres. The company, which employs a staff of 70 in
France, enjoyed a 2007 turnover figure of 17.5 million euros.
The main activity of WEIR MINERALS France is the manufacture and
sale of pumps for slurry. These are used in the minerals and mining
industry, sand and gravel industries, sewerage, water treatment,
the paper industry, the food industry and the chemical
industry……
Some of these applications are highly original and demonstrate
the central role played by WMF products in every area: the food
industry, building and civil engineering, the environment and
industry in general.
