Sewage Treatment Ireland, Water Treatment Chemicals, Water Testing

Vacuum Sewer System from Roevac ®

Overview
High groundwater table, low population density, flat terrain (lack of natural slope), unfavourable soil conditions like sandy, unstable or rocky ground are the ideal circumstances in which to use Roevac ® vacuum sewer systems. In areas along rivers, lakes or coasts as well as in water protection zones, vacuum sewerage is often the only choice. Moreover it offers specific advantages for residential areas where the wastewater flow is low or varies over a wide range (e.g. tourist areas). Other benefits include independence from terrain topography, small pipe diameters, high flexibility and low maintenance costs.

The advantages are also evident in the construction phase: small pipe diameters result in narrow trenches and reduced excavation. This allows streets and footpaths to be used during construction works - a benefit which the residents and road users in the immediate vicinity highly appreciate. In addition, vacuum sewer and water mains can be laid in the same trench.

Wastewater from a vacuum sewer pipe network is collected in a central vacuum station via differential air pressure. From there, the wastewater is forwarded to a wastewater treatment facility or to other sewer collection systems (via central force main, gravity sewer, etc.). The vacuum station typically includes one or two vacuum vessels, several vacuum pumps, two non-clog sewage pumps, and a control panel. The pipeline system is maintained under vacuum at all times by the vacuum pumps.

A pipeline network connects the vacuum station with collection chambers that are typically installed adjacent to the private houses. The collection chambers equipped with interface valve units are the transition between the conventional gravity lines from the houses and the vacuum system. Wastewater flows by gravity from a house into a collection chamber’s sump. After a given quantity (batch) of wastewater accumulates in the sump, an interface valve automatically opens. The interface valve uses differential air pressure (atmosphere & vacuum) as its energy source. No electrical power is required at the collection chambers. After approximately 5 seconds the valve closes and the process can start again.

Advantages
In comparison to conventional gravity or pumping systems the ROEVAC ® vacuum system offers the following important advantages to residents and operators:

Considerable savings in construction costs
Much shorter construction period
Pipelines laid in shallow and narrow trenches
Small diameter pipelines (DN 80 – DN 200)
Flexible pipeline construction
Easy to lay pipelines around obstacles
Sewers and water mains can be laid in a common trench
Systems closed to the atmosphere with no leakage or smell
No manholes along the vacuum sewers
One central vacuum station can replace several pumping stations

Applications

Compared to conventional methods of sewerage, vacuum technology is highly applicable in the following circumstances:

The topography is flat
Groundwater table is high
Sewer system is located near a lake, river, coastline or floodplain
Ground has an adverse gradient
Wastewater flows are highly variable e.g. holiday establishments or local recreational facilities
Difficult ground conditions e.g. rock, running sands, peat, swamps etc.
Refurbishment of sewer systems
Rural area where houses and buildings are not close to each other
Crossing rivers, streams, railwaylines, major road etc.
Groundwater protection areas