Sewer Rehabilitation & Renewal

Replacing collapsed legacy sewers in dense, live urban wards.

Overview

Renewal of failed brick barrel and RCC sewers in congested old-city wards, where the constraint is working room and disruption rather than pipe cost. Short handling lengths, open-cut in narrow lanes and trenchless crossings under live carriageways.

Specification

Product range: Alcorr DWC HDPE
Standard: IS 16098 (Part 2)
Renewal Sizes: ID 150 mm to ID 800 mm
Stiffness Class: SN 8 / SN 16
Standard Code: IS 16098 (Part 2)

Why HDPE here

Light enough to carry into lanes no excavator can reach
Sealed socket joints stop the exfiltration that undermines adjoining foundations
Replaces a corroded barrel with a 75 to 100 year asset rather than another patch

Typical deployments

Old-city ward sewer renewal
Collapsed brick barrel replacement
Trenchless carriageway crossings
Property connection re-laying

Reference project

OWSSB Trenchless Sewerage — Odisha Water Supply & Sewerage Board

Specification and site notes

Survey before you size

A legacy brick barrel is rarely the diameter the record says, and it has usually silted. CCTV survey the run and size the replacement on the catchment as it is now, not on the drawing. Renewal is the one chance to correct an undersized reach.

Handling length is the real constraint

In an old-city lane the limit is what a crew can carry past parked vehicles and shopfronts, not what a crane can lift. Order 6 m sticks rather than 9 m or 12 m for these wards, and stage deliveries daily so the lane is never blocked overnight.

Exfiltration is why the road settled

A leaking sewer washes fines out of the surrounding soil, which is what causes the road settlement and the foundation cracking that usually triggers the renewal. A sealed socket joint is the point of the exercise, so air-test each reach before reinstatement.

Live connections

Property connections have to be transferred as the new line goes in. Saddle connections onto DWC are made with a purpose-made clamp; do not core and mortar into the corrugation, which is where a renewed line starts leaking again.

FAQ

Why replace a brick sewer with DWC HDPE rather than reline it?

Relining keeps the existing alignment and loses bore. Where the barrel has collapsed, or the reach was undersized to begin with, replacement in DWC HDPE gives back full section, a corrosion-immune material and a sealed joint, for a 75 to 100 year asset instead of another intervention in a decade.

Can DWC pipe be installed in lanes too narrow for plant?

That is one of its main advantages here. A 6 m stick of mid-range DWC is carried by the laying crew, so renewal reaches wards where an RCC pipe simply cannot be delivered to the trench.

How are property connections made into a renewed DWC sewer?

With a purpose-made saddle clamp seated on the corrugation. Coring the wall and mortaring a connection in is what makes a renewed line start leaking again, so it should not be permitted on site.

Does the new sewer need to match the old diameter?

It needs to match the catchment. Legacy reaches are often undersized or silted, and renewal is the only practical opportunity to correct that, so size from a CCTV survey and a current flow calculation rather than from the historic record.