Imhoff Tanks

Description of System.

Imhoff tanks, sized in accordance with the provisions of the Official Gazette No. 48 of 21 February 1977, consist of two internal chambers: an upper chamber for sedimentation and a lower chamber for digestion.

The wastewater enters the sedimentation chamber where the suspended settleable solids slide down the sloping walls of the hopper into the collection and digestion chamber below through a connecting longitudinal slot.

To reduce the velocity of the wastewater flow in the tank, to distribute the flow evenly over the whole vertical inlet surface and to minimise turbulence that could disrupt the sedimentation process, protective guards (baffles) are immerged in the liquid near the inlet and outlet pipes.

In the lower chamber of the tank there is no oxygen (anoxia) so the sludge that settles on the bottom is stabilised; this mineralisation process is known as the “anaerobic digestion” of the sludge.

Supplied as standard

Gazebo Imhoff tanks are fitted with:

  • PVC sleeves sealed watertight to connect the inlet and outlet pipes,
  • AISI 304 stainless steel scum baffles for inlet and outlet pipes,
  • AISI 304 stainless steel sheet plates inside the tank to form the hoppers,
  • sludge extraction pipes.

FRC Gazebo System.

The Fiber-Reinforced Concrete (FRC) Gazebo System is the most advanced system for manufacturing prefabricated monolithic tanks.

Research and development into this fiber-reinforced concrete system was carried out in collaboration with the R&D department of BASF Master Builder Solutions.

Together Gazebo and BASF have come up with second generation monolithic tanks offering outstanding benefits:

  • Greater durability
  • Increased ductility
  • Greater tensile and flexural strength
  • Improved chemical resistance in aggressive environments
  • Total absence of micro cracks
  • Complete impermeability
  • Greater fire resistance
  • Reduction of environmental pollution.
Technical features of the FRC

FRC is made with synthetic fibers, obtained from the extrusion of polypropylene-based polymers.
This enhances the strength of the concrete, considerably increasing its toughness and ductility.

The FRC curing process is accelerated by hardening catalysts but without using steam.
Adding special nanoparticles diluted into a water suspension to the fresh concrete mix helps increase the internal hydration temperature and thus speeds up the curing process.
Thanks to this innovative technique, the thermal energy normally generated is eliminated, it is easier to control the curing temperature, the mould release time of the prefabricated elements is reduced to within 10 hours of pouring, and the compressive strength of the concrete, even after short curing, is considerably higher: 35-40 N/mm 10 hours after being poured.

FRC is water-repellent.
FRC is water-repellent because it contains innovative chemical additives with a very high degree of fineness, sealing the capillary porosities which are created between the cement particles.

SPECIFICATIONS

  • Made with PORTLAND CEMENT (in compliance with UNI EN 197-1) with type 1 mineral additives (calcium carbonate “ventilated filler”) and aggregates that comply with UNI EN 12620.
  • SCC mix.
  • Contains synthetic fibers obtained from the extrusion of polypropylene-based polymers.

COMPRESSIVE STRENGTH
C50/60 (Rck ≥ 600 kg/cm2)
C60/75 (Rck ≥ 750 kg/cm2)

EXPOSURE CLASSES (in compliance with UNI EN 206-1)
XC4 (concrete resistant to corrosion induced by carbonation),
XS2/XD2 (concrete resistant to corrosion induced by chlorides),
XF1 (concrete resistant to freeze/thaw attack),
XA2 (high sulphate resistant concrete),
XA3 (very high sulphate resistant concrete).

SPREAD CLASSES
SF2
SF3

Characteristics of the FRC monolithic tanks

  • Greater tensile and flexural strength of the concrete.
  • Crack resistance:
  • – resistance to first crack: 4.00 MPa
    – residual crack resistance: 1.00 MPa.

  • Internal steel reinforcements with upgraded adhesion and type B450C electrically welded mesh, factory tested, in compliance with Italian Ministerial Decree of 14.01.2008.
  • External and internal surfaces with open face finish which is totally free of porosity and gravel nests.

SCC Gazebo System.

“The “SCC Gazebo System” uses innovative Gazebo technology and a unique production process to manufacture prefabricated monolithic tanks using self-compacting concrete (SCC).

Gazebo uses rotating formwork to produce the tanks and the concrete curing process is achieved quicker and without steam.

Result: the structure is extremely solid and strong, the tanks have more aesthetic appeal and are perfectly watertight, even when installed above ground. In other words, greater durability, greater safety, no problems.

Features of self-compacting concrete (SCC)
  • Made with PORTLAND CEMENT (in compliance with UNI EN 197-1) with type 1 mineral additives (calcium carbonate “ventilated filler” ) and aggregates that comply with UNI EN 12620.
  • The quicker concrete curing process is achieved without steam giving it considerably greater strength.

COMPRESSIVE STRENGTH
C50/60 (Rck ≥ 600 kg/cm2)
C60/75 (Rck ≥ 750 kg/cm2)

EXPOSURE CLASSES (in compliance with UNI EN 206-1)
XC4 (concrete resistant to corrosion induced by carbonation),
XS2/XD2 (concrete resistant to corrosion induced by chlorides),
XF1 (concrete resistant to freeze/thaw attack),
XA2 (high sulphate resistant concrete),
XA3 (very high sulphate resistant concrete).

SPREAD CLASSES
SF2
SF3

Characteristics of the monolithic tanks

  • Internal reinforcements in improved adhesion steel with type B450C electrically welded mesh, factory tested, in compliance with Italian Ministerial Decree of 14.01.2008.
  • External and internal surfaces with open face finish which is totally free of porosity and gravel nests.

Accessories.

  • special coatings on the internal and external surfaces of the tank,
  • pedestrian/vehicle covers,
  • manhole covers in ductile iron/galvanised metal sheet /stainless steel,
  • can be installed in the presence of groundwater.

Applications.

Residential communities, production facilities, farms, abattoirs, tourist facilities, public bodies.


CE marking.

In compliance with the provisions of UNI EN 12566-1.


Gazebo for professionals.

Gazebo helps designers, plant engineers, building contractors. It offers free design services, technical support, promptly drawn up projects, on-site visits and inspections, technical assistance up to installation and short lead times.

Progettazione gratuitaSupporto tecnicoVelocità di preparazione del progettoSopralluoghi in cantiereAssistenza tecnica fino all'installazioneVelocità di consegna

Technical documentation.

Professionals interested in specifications, diagrams, tables, technical drawings, dwg and pdf files can access the technical documentation after registering or can fill in the form below for further information.

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