Retention tanks

GRP retention tanks are used to store rainwater, sanitary sewage as well as raw and drinking water. Tanks can also be used as housings for pumping stations, shut-off fittings, venting and aeration fittings. Tanks are made of GRP pipes as monolithic tanks up to a capacity of 50m3 and segmental tanks composed of pipes and inspection chambers up to a capacity of several thousand m3.

GRP DUKO underground tanks are built in various configurations in terms of shape, capacity and purpose. We divide the tanks into:

  • retention tanks for rainwater and meltwater (optionally with the possibility of infiltration)
  • retention tanks for combined sewage (optionally with an overflow edge)
  • storage of raw and drinking water
  • separation of sand fractions and petroleum liquids
Installation of retention tanks can be done directly in an open trench or using trenchless jacking techniques.


Shape and configuration of retention reservoirs:

  • linear as a gravitational channel with a locally increased diameter
  • parallel so-called tank batteries
  • labyrinth connected in parallel
  • unevenly built into the available space


 Have questions? contact our specialists: engineering@dukoinzynieria.pl r.walczak@dukoinzynieria.pl


Elements of retention reservoirs

  • GRP pipes in the diameter range of 500÷4000 - standard for open excavation or jacking,
  • inspection chambers are usually integrated with a centric or tangential manhole pipe or with an additional landing and a stainless steel ladder and access steps,
  • semi-spherical blanking heads (the most optimal for loads), cylindrical or flat ribbed (for shallow installations),
  • spigots made of GRP and PVC, PP, PE, steel.

In addition, retention reservoirs can be equipped with control and measuring devices so that their operation runs smoothly and efficiently. We include:

  • flow regulators: centrifugal, weight, jet, float,
  • fittings that cut off the flow at the outlet from the tank or between retention chambers,
  • water and sewage level measuring equipment,

Advantages of GRP tanks (retention tank):

  • total resistance to chemical corrosion,
  • very quick assembly (no welding or welding),
  • any size and construction of fittings and inspection chambers,
  • large selection of diameters in the range of 500÷4000 mm - 33 diameters!,
  • the possibility of using trenchless methods,
  • self-cleaning effect at small drops,
  • low investment costs (cheap transport, cheap construction equipment, quick installation),
  • any cross-section of the tank (pipes with a circular cross-section, circular with a base in the bottom, non-circular, e.g. bell-shaped, egg-shaped and other pipes are available.