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Service
Research
Engineering
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Dissolved Air Flotation Units - DAF
Water and Wastewater Treatment Plant Equipment
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Beyond full plant planning and construction,
we supply CE certificated dissolved-air flotation (DAF)
units. Air Flotation is applied to the clarification of wastewater
to meet effluent discharge requirements; to recovering suspended
material or for reclaiming water for reuse; and to the thickening
of slurries and sludges prior to disposal, further treatment or
dewatering. Dissolved-air flotation is best applied to remove
materials and solids that normally settle slowly, persist in remaining
in suspension, or have a tendency to float.
The available models cover a great range of capacities suitable
for any requirements
(from 1 to 80 m3/hour and more)
The DAF unit is applyed in wastewater treatment plants in dairy,
meat processing factories mechanical productions with oil and
grease poluted wastewaters, and many other as well.
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Flotation is a process to separate
suspended or emulsified matters from the liquid phase floating
them through the action of a rising gas stream, normally air.
The gas can be, either injected, or dissolved under pressure
into the water. In the first case (IAF or induced air flotation),
air is simply introduced into the water by a compressor and
air diffusers. The air bubbles diameter varies from 1 to 5 millimetres,
according to the used diffusers. In the second case (DAF or
dissolved air flotation), air is dissolved under pressure into
the water to produce, once pressure is released, air bubbles
with a diameter of 20 to 50 microns that saturate the whole
liquid mass. The result is the formation
of a light particulate that quickly rises forming a layer on
the surface of the clarified water. The pressurising system
used in our DAF units (continuous circulating of the mixture
from the group of saturation to the one of dissolution) allows
to obtain over saturated water/air mixtures with low power and
low energetic consumption. Moreover, this system allows to introduce
air to an independent pressure from the working pressure of
the saturation group, avoiding thus the installation of additional
compressors.Wastewater to be treated enters a reaction coil
particularly shaped to allow a thorough contact and complete
mixing with the dosed chemicals.
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Chemical processing
plants
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Pulp and paper mills
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Oil water separation
in the oil industry and polutions in wastewater
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Food processing industry,
dairy, meat processing factories, sweets, destillery, wine
production and farms
- Textile and other industries
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The dosage of chemicals
in the reaction coil is carried out with high reliability systems
and high performances metering pumps. The control of the pH
is always on-line with industrial instruments of great precision
and electrodes of combined type in solution gel. The water/air
mixture is injected after the chemicals dosage in many different
points of the reaction coil and flotation tank, to obtain the
most uniform possible distribution of its concentration in the
fluid mass and an intimate contact with the flocks to be removed.
In this way, already in the reaction coil the flocks produced
by the reaction with the dosed chemicals absorb air particles,
to advantage of the reliability of the process and of their
rising speed.
The flow of the saturated water/air
mixture and wastewaters conditioned with the chemicals, is then
introduced in the flotation tank through a conical profile ejector
to increase in a progressive way the rising speed of the solid
flocks stuck to the air bubbles. Thus, a thick layer of floated
materials grows on the surface of the flotation tank and it
is removed by a scraper. The conveying course of the floated
materials to the collection hopper, is built with a curved profile
connection, so to facilitate the water-drainage and achieve
a high concentration of dry matter into the discharged sludges.
A specially shaped telescopic valve collects clear water and
allows to control the level into the flotation tank, thus the
quantity of sludge to be removed. The water flow speed is calculated
non to disturb the rising of lighter materials and the sedimentation
of the heavier. Settled materials are discharged through an
automatic valve.
The software controlling and ruling
the entire process is of high reliability (written for PLC SIEMENS,
but exportable also to other PLC on request) and guarantees
always the best conditions and performances of treatment. A
remote control of the operations with a SCADA interface is available
as option, as well as the transfer of all the working data on
a PC with a TCP/IP protocol.
These and other constructive particulars, make these machines
particularly fit for the treatment of industrial wastewaters,
in particular from industries of the oil, mechanics, galvanic
and textiles, refineries, as well as any alimentary industry
as dairies, meat processing industries, sweet and chocolate
industries, wine, beer and liquors industries.
The available models cover
a great range of capacities (from 1 to 80 m3/hour and more)
and may be completed with modular units for a complete treatment
of wastewaters, such as chemical oxidation, filtration on resins,
quartzite and activated coal, units for biological treatment,
etc.
All the units are completely built in stainless steel AISI304
made to last, other materials on request.
DAF units are supplied ready to be installed, on request installed,
starter and tested by our technicians.
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All DAF units have CE certifications and are supplied with
complete use and maintenance handbook.
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