FLOVAC VACUUM PUMP STATION

The heart of every Flovac vacuum sewer system. Designed, built and supported for the long term

Intro – VPS in Context

The Vacuum Pump Station (VPS) is the heart of a Flovac vacuum sewer system, but it doesn’t work alone. It’s the point where the interface valves and vacuum mains connect back to a single collection point, where sewage is discharged to the treatment plant, and where the whole network’s performance can be seen and managed. Every VPS Flovac supplies is engineered as part of a complete system, not sold as a standalone piece of equipment.

The VPS houses the collection tank, discharge pumps, vacuum pumps, and the controls that automate the station and maintain negative pressure across the network.

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Overview

A single VPS is usually sufficient for an average-sized catchment area.
All electrical and mechanical equipment is housed in a dry environment, operators are never in contact with wastewater.
Odours are minimised through Flovac’s bio-filter, sized and maintained as part of the system design.
A VPS is ideally sited centrally within the catchment, though this can flex to suit the designer’s needs.
A backup generator can be installed at the VPS to keep the system running through power outages, storms, or cyclones.

Collection Tanks Built for the Long Term

The majority of Flovac’s collection tanks are now Stainless Steel 316. Earlier systems used mild steel and fibreglass, and tanks of that generation are still in service in a number of installations, but 316 stainless is now the standard choice for new stations, given how it stands up to wastewater’s corrosive nature and to the atmospheric conditions of the coastal and seaside sites where many Flovac systems are installed.

Tanks are configured as vertical or horizontal depending on the site, each with an operating volume and a buffer volume. Sewage collects under negative pressure until the tank reaches roughly two-thirds full, at which point the discharge pumps send it on to the treatment plant. This fill level, along with the rest of the collection tank’s behaviour, is visible through Flovac’s monitoring system, giving operators early warning of unusual fill patterns rather than surprises at the plant.

Non-clog sewage pumps

Flovac uses non-clog centrifugal pumps with a 90mm through-clearance. Horizontal pumps are the more common choice, since they self-prime without needing equalisation lines.

Because these pumps discharge against a negative pressure in the collection tank, designers need to account for suction conditions carefully at the selection stage, get it wrong and cavitation follows. Variable speed drives (VSDs) are commonly used to give the system flexibility for staged developments or variable inflow conditions.

Vacuum Pumps

Flovac typically specifies rotary vane or dry claw vacuum pumps, with liquid ring pumps used on select applications. The system operates at -0.5 to -0.7 bar (15–21 inHg), a range that keeps pump run time efficient in a well-tuned network.

In a well-designed and well-maintained system, vacuum pumps typically run around 4–6 hours per day. Monitoring the air-to-liquid ratio is one of the more telling day-to-day indicators of system health, a shift in that ratio is often the first sign something in the network needs attention.

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Monitoring – visibility across the network

Flovac supplies monitoring for both the vacuum network and the vacuum pump station, and many clients also integrate this with their own SCADA systems. Tracking indicators like vacuum loss per kilometre by line, static budget utilisation, and pump run-time patterns gives operators an early, practical read on system condition — long before an issue would otherwise surface. This operational visibility is a core part of how Flovac supports a system for the long term, not just at handover. For more on Flovac’s Remote Monitoring Systems, click here.

Odour Control

Odour is rarely an issue with vacuum sewerage, because sewage doesn’t sit long enough in the network for septicity to develop. As standard practice, air drawn through the vacuum pumps is treated through a mulch-bed bio-filter.

Sizing and maintaining the bio-filter correctly matters, get it wrong and back pressure can affect the system. Flovac tends not to use charcoal filtration for vacuum sewage systems, since the warm, moist air coming from the process makes charcoal less effective than a properly maintained mulch bed.

VPS buildings – designed to fit the community

VPS buildings can be sized and designed to suit the site — from a compact 10-foot shipping container up to a footprint similar to a standard house block. Where a station sits within a residential or community setting, the building itself can be finished to blend in, as several of Flovac’s operators have done by having local community members paint their station.

Designers need to plan for truck access, a generator hard stand, and odour control alongside the building footprint itself.

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Thinking about upgrading an existing VPS?

Flovac’s engineering group has designed more than 300 vacuum pump stations worldwide, there’s a reasonable chance we designed the one you’re now looking at upgrading. That history matters, because a VPS is engineered as a set: pumps, controls, and vacuum profile are all sized to work together, and changing one on its own can shift how the others perform. A pump change can affect heat inside the station, which in turn affects pipe materials, venting, and odour control. A controls change can alter how the whole station responds to the network.

An upgrade is also a good moment to look at the catchment with fresh eyes, have daily flows changed, has infiltration crept in, is there room to take on more connections. We’d also flag one specific trap: VSDs are sometimes added to a station to try to fix vacuum or line-flooding issues, but they can end up disguising the underlying problem rather than solving it, and increase run hours over time instead of reducing them.

We’re seeing more utilities design and carry out VPS upgrades without referring back to Flovac, and running into avoidable problems as a result. If you’re planning any change to a VPS’s pumps, controls, or capacity, talk to our engineers first — it’s a conversation worth having before the equipment order goes in, not after.

Deployable and temporary pump stations

Not every project needs a permanent VPS from day one. Flovac can lease and install temporary pump stations to service a development ahead of the main station being built — useful for staged developments, early-stage catchments, or where connections are coming online faster than permanent infrastructure can be commissioned.

For projects that need a fully mobile solution rather than a staged one, Flovac’s Deployable Vacuum Systems extend the same approach further — a complete, relocatable vacuum system that can be brought onto site, commissioned quickly, and moved on once it’s no longer needed. Both options let a development start collecting wastewater without waiting on permanent civil works, and both are backed by the same monitoring and support Flovac applies to a fixed installation.

Suits staged developments where full connection numbers build up over time.
Avoids sequencing risk — no waiting on permanent station construction before wastewater collection can begin.
Same controls, monitoring, and Flovac support as a permanent installation.
Read More about Deployable Systems Here