TPT March 2011

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66 March 2011 ›
Technology Update
THE efficiency of wastewater treatment
systems to clean wastewater has improved
continuously over the last few decades.
Stormwater discharge is the main source of
pollution of waters today. Legal framework
requirements demand the rethinking of the
subject of stormwater.
The EU Water Framework Directive
demands ‘good conditions’ for all European
water bodies, and the new German Federal
Water Act (Wasserhaushaltsgesetz- WHG),
adopted in March 2010, bans new combined
sewer systems. It demands stormwater
infiltration or discharge without pollution
with wastewater for all of Germany.
Many cases require cleaning of the
stormwater runoff to avoid pollutants being
transported into water bodies and ground
water. With the Sedi-pipe programme,
Fränkische Rohrwerke, a leader in the field
of stormwater management, has created an
efficient solution for this.
Sedimentation is observedwhen particles
of solid material slowly sink to the ground in
a jar of water. All this requires is gravity and
enough time. Stormwater sedimentation
tanks have used this principle for a long
time. Stormwater is diverted through large
concrete tanks, the flow velocity is slowed
down and dirt particles sink to the ground.
For the sediment on the ground not to be
stirred up and discharged in case of heavy
rainfall, these tanks must be at least 2m
deep. This makes significant tank volumes
necessary.
Sedi-pipe accomplishes this more
effectively: sedimentation takes place in a
horizontal pipe with a built-in flow separator.
This special lattice creates a zone with little
water movement, from which the sediment
is not discharged during heavy rainfall. This
achieves the same cleaning performance
as a stormwater sedimentation tank, but
with a much smaller volume.
The fineandultra-fineparticles contained
in the stormwater bind the largest amount
of pollutants due to their large surface. The
aim is to retain these particles in particular,
and it takes a long time for these particles
to sink. The long form of the sedimentation
pipe is an advantage here, because it
reduces the time and distance until a
particle settles, and therefore very fine
particles settle.
The flow separator prevents the parts
from being remobilised and therefore from
being discharged during heavy rainfall.
Sedi-pipe therefore retains large amounts
of fine particles and consequently large
amounts of the pollutants. The performance
capacity has been tested and confirmed by
independent institutes.
Existing Sedi-pipe systems are intended
for use in upstream infiltration systems,
especially in interaction with Rigofill
retention/infiltration units.
With Sedi-pipe XL, Fränkische
has increased the number of possible
applications of the Sedi-pipe, allowing high
cleaning performance when large areas are
connected before infiltration or discharge
into receiving waters. Through project-
specific design, cleaning performance
and pipe diameter can be designed to
suit individual requirements. Extra large
storage volumes for light liquids (spill
prevention) and mud are also possible.
The shallow installation depth compared
to regular stormwater sedimentation tanks
facilitates building under high ground water
conditions.
The Sedi-pipe XL series consists of four
system sizes: 600/6, 600/12, 600/18 and
600/24. The systems can be combined into
large-scale systems to replace standard
stormwater sedimentation tanks.
Building specifications are usually very
clear: the system should be space-saving
and below ground, installation should be
easy and fast, and in case of possibly high
levels of ground water also achievable with
low installation depths. Furthermore, the
requirements of water regulations must be
met. “Sedi-pipe systems meet all of the
above requirements,” commented Michael
Schütz, head of product management.
The system maintains a constant water
level, which keeps the sediment muddy.
Maintenance of the system is usually
performed during regular sewer flushing
and only requires vacuuming of the
contents. The slope of the sedimentation
pipe causes the mud to slide to the low
point of the system in the start shaft. If
required, cleaning can be supplemented
by using high-pressure jetting. Sedi-pipe
XL shafts are accessible for maintenance
and inspection if necessary, and have a
diameter of 1,000mm.
Fränkische Rohrwerke – Germany
Fax: +49 9525 88 412
Email:
Website:
High-performance sedimentation systems
CARELL is the exclusive North American
distributor and support/service provider
for a new half pipe jacket manufacturing
technology that is claimed to save
production time and manpower to uniformly
form and apply high quality half pipe jackets
to thermally conditioned tank shells.
At the Fabtech 2010 show in Atlanta,
Carell displayed a stainless steel tank shell
with low profile half pipe jackets. This jacket
was automatically formed and welded to the
shell in this new high tech production cell.
The half pipe is formed from slit coil stock in
a continuous progression. Various shapes
and material gauges can be used. Coil pitch
can be varied as the half pipe is applied to
the tank shell. The one pass system can be
designed to handle various tank diameters
and lengths.
Carell Corporation – USA
Fax: +1 251 937 0957
Email:
Website:
Coil and weld half pipe jackets
simultaneously
Carell’s stainless steel tank