Attenuation Sewers

Attenuation sewer systems are made up from internal and external precast overflow manholes which have a sewer of up to Ø2000mm diameter between them. Overflow manholes can be made as a standard manhole or a vario-manhole if a larger overflow manhole is required.

Maximum Water Storage capacity per m¹
Ø825 540 Litre
Ø900 640 Litre
Ø1050 870 Litre
Ø1200 1130 Litre
Ø1350 1430 Litre
Ø1500 1770 Litre
Ø1800 2540 Litre
Ø2000 3140 Litre

Concrete precast settlement tanks and storage reservoirs

The reservoirs are made out of precast wall and roof elements on an in-situ constructed or precast slab. The installation of the precast elements can start as soon as the concrete base has hardened. The connection between the wall elements and the in-situ poured floor is realised through a so called “hairpin’’ connection around the outside of the reservoir/tank which can be poured as soon as the panels are set to the correct line/level.

Sequence of construction for the placing/leveling of precast elements:

  1. The wall elements will be placed and leveled on shims so the face of the wall lines up with the proposed inside of the tank/reservoir. The wall elements are secured by push-pulls and bolts.
  2. The hairpin connection can be poured around the outside of the tank/reservoir. As soon as the concrete has hardened the push-pulls can be removed.
  3. The filling of the vertical joints between the wall elements will be done with non-shrinkable grout.
  4. After the vertical joints are sealed the precast roof elements can be placed on top of the wall sections. There is a bolted connection between the wall and roof modules. The bolts will be sealed with non-shrinkable grout at a later stage of construction. If needed, or there is chance of floatation of the structure due to a high water table, the roof slabs can be made with a shutter around the outer edge so that a pressure layer of in-situ concrete can be poured. Once again, there is no need to make shutters.

Benefits of the Precast Reservoirs/Storage Tanks/UIDs/CSOs

  • Environmentally-friendly design
  • Design
    One of multiple compartments, the height and width dimensions are variable; there are no technical limitations.
  • Reduced construction time
    After installing the precast elements the ground can be back filled and if there is ground support or de-watering they can be removed. No shuttering is required.
  • Cost
    Labour cost on-site is minimal when compared to traditional systems.
  • Minimum impact on the surrounding area
    Therefore environmentally-friendly.
  • Minimal time of de-watering
    Reduced logistical disturbance for the people living in the surrounding area.
  • Watertight guarantee
    All structures are completely watertight when installation is carried out according to Kijlstra’s instructions.
  • Connections
    Through the use of a rubber ring connection, the connection between sewer system and the tank is both flexible and watertight. Various connections are available to suit different applications and pipe types.
  • Excellent price/quality ratio
  • High-quality products
    Produced in a factory-controlled environment, weather conditions have no impact on the production process. Optimal degree of density of the product, so there is no segregation. Concrete quality is C35/45. Kite Mark, KOMO product certificate, building elements of concrete, number K12768.
  • Health and safety benefits
    The use of Kijlstra precast systems, which act in accordance with the latest CDM regulations, greatly improves health and safety in reducing manual handling, the use of wet concrete and associated risk of concrete burns, the use of vibrating tools and associated risk of white finger syndrome, the requirement for access through a confined space, and the need for associated procedures.
  • Environmentally friendly
    Reduction of wastage on-site from shuttering, ready-mix concrete and associated machinery and delivery vehicles.