At T-T, the team is regularly asked to review and support wastewater designs where long-term operational performance is critical. That trust is built on one thing: experience grounded in evidence.
On a recent project, they challenged a request from another UK NAV to increase the diameter of a rising main. The reasoning presented followed familiar industry assumptions—that larger pipes are more reliable, reduce blockage risk, and better suit commonly available pump configurations.
Their review showed otherwise.
Because they do not rely on convention alone. They validate, emulate, and assess designs against real operational data—the same conditions assets will face once they are built, commissioned, and maintained.
Understanding the Risks That Matter in Operation
One of the reasons water authorities and contractors work with T-T is their focus on what happens after handover.
Septicity remains one of the most serious risks in wastewater networks. It develops when sewage is retained in anaerobic conditions, most often within rising mains. The resulting hydrogen sulphide (H₂S) is corrosive, odorous, and presents real safety risks for operational teams.
Design decisions that increase retention time directly increase this risk. In their experience, septicity is rarely a theoretical problem; it is an operational one, with real cost, safety, and reputational consequences.
Evidence, Not Assumption
In this case, the proposed diameter increase—from 80 mm to 100 mm—appeared marginal. Their analysis showed a very different reality:
- 600 m of 100 mm rising main: 4,713 litres
- 600 m of 80 mm rising main: 3,016 litres
That is a 56% increase in retained volume.
From an operational perspective, a 20 mm increase does little to improve solids passage under pressure. What it does do is significantly increase residence time, particularly on modern developments where flows are often below one dry-weather flow.
This is where their experience adds value. They understand how assets behave in the field, not just how they perform in a calculation.
Pump Selection Informed by UK Network Performance
Their pump and impeller recommendations are based on performance across UK wastewater networks. Four-pole vortex pumps consistently provide the most robust solids-handling capability in real applications.
While alternative impeller designs may appear more efficient on paper, they see higher blockage rates in practice. For operators and contractors, reliability always outweighs marginal efficiency gains.
Designing for the Whole Lifecycle
Water authorities, NAVs, and contractors work with T-T because they design for the entire lifecycle of the asset, not just adoption compliance.
The DCG ensures post-adoption standards are met. But the two to four years of private ownership before adoption is often where avoidable risk, maintenance cost, and developer dissatisfaction arise.
Their role is to help eliminate those issues before they are built in.
A Partner, Not Just a Supplier
Everything advised by T-T is based on recorded data, operational experience, and demonstrable outcomes. They support designers, contractors, and water authorities by challenging assumptions early and ensuring assets perform as intended long after installation.
That is why their partners trust them—and why working with T-T results in better-performing, lower-risk wastewater infrastructure.
Speak to the Experts
If wastewater designs are being reviewed, adoption challenges are being faced, or there is a desire to reduce long-term operational risk, the T-T team is ready to help.
Call on 01630 647200 or email: pumpingstations(Replace this parenthesis with the @ sign)ttpumps.com
Telephone: +44 (0)1630 647200
Website: www.ttpumps.com