Renovation and rehabilitation of sewers 

Worn-out sewerage systems result in an unnecessary impact on the water environment. Sewerage systems in bad condition lead to needless operational failures often resulting in flooding of basements, roads and public areas. Furthermore, worn-out sewerage systems result in rats having free access to sewers through damaged pipes and poor joints. All of these situations create nuisances for the public.

NO-DIG renovation

COWI has a team of experts specialising in NO-DIG renovation, with wide experience of all kinds of trenchless technology methods, e.g.:

• Cured-in-place lining
• Sliplining
• Roll down and sewer lining
• Pipe bursting and jacking
• Tunnelling and microtunneling
• Directional drilling
• Localised repair

Investment in new sewers

To comply with environmental and operational requirements of modern systems for transport of wastewater, many municipalities are facing heavy investments in new sewerage systems. Often, investments are targeted towards renovation of existing sewerage systems applying NO-DIG solutions. This is a result of the high construction costs involved in the establishment of new sewerage systems using traditional digging and trenches.

Tender projects

When tendering NO-DIG projects, COWI uses GIS-tools for the preparation of sewer layout plans. Many projects also include TV inspection and hydraulic analysis. This provides the basis, upon which, the selection of method is decided in collaboration with the client.