Keeping Live Sewer Flow Moving

A critical sewer doesn’t stop because repair work starts.

When relining works are staged across a live trunk main, the temporary bypass needs to keep flow moving safely as the project progresses.

The client

Pipeworks

The project 

The Western Trunk Sewer Main is a critical wastewater pipeline running down the western side of the Hutt Valley – including sections near and under State Highway 2.

• Main contractor: Reline the pipeline to extend its working life without open trenching or major disruption to the surrounding environment.

• Fluid Management: Safe sewer bypass pumping to temporarily divert live sewer flows around each section of pipeline being relined.

Planning a challenging bypass job? Get in touch today about keeping sewer flows moving safely.

The challenge 

• Keep the sewer network operating without incident. 

• Maintain flow while each section of the trunk main was prepared, relined and returned to service, working around flow requirements, access points and site constraints and public access.

• During stage three, the work became higher risk, with the bypass operating in the stop bank beside the river.
  

Stage three placed the bypass in a higher-risk riverside environment

The solution 

Prime configured a temporary sewer bypass setup around the conditions of each stage.

The priority was keeping the network operating safely – maintaining flow 24/7, building in redundancy and giving the client confidence while relining works continued.

BBA BA180 pumps provided the pumping capacity, with two duty pumps and two pumps held on standby for 100% redundancy.

That solution included:

• Automatic response – high-level alarms to activate the standby pumps if needed

• Remote monitoring – visibility of pump performance while operating

• Backup fuel capacity – supporting 24/7 operation if site access became difficult

• A 24-hour trial run – confirming the setup could handle live flow.

A new outlet valve was also trialled to make drainage, cleaning and maintenance easier on site.

100% redundancy – with duty and standby pumps ready to keep flow moving

The outcome 

The bypass did what it needed to do – it kept the sewer network operating safely while relining works continued.

Across the completed stages, the setup delivered:

• Zero spills

• Zero stoppages

• Zero downtime.

With a responsive team in place, clear monitoring and no bypass failures, Pipeworks had confidence that flow was well managed and the surrounding environment was protected.

The result was less uncertainty on a high-consequence job – and a temporary bypass setup the client could trust through later stages.

Hands-on support helped keep the bypass running 24/7

Want the practical breakdown? Read more about temporary sewer bypass pumping and what makes a bypass reliable.