Sewage Treatment Ireland, Water Treatment Chemicals, Water Testing

Vacuum Sewer System from Roevac ®

How it works:

Depending upon the topography, wastewater can be collected within a radius of many kilometres around the central vacuum station. Wastewater flows through a conventional gravity drain from each house to a ROEVAC ® collection chamber installed outside the building. When a pre-determined volume of wastewater is collected in the collection chamber sump the hydrostatic pressure activates a pneumatic controller. This controller opens a pneumatic vacuum valve and the wastewater in the chamber is completely evacuated into the vacuum sewer pipe. No electricity is required at the collection chamber with all operations entirely pneumatic.
As air is admitted through upstream vacuum valves, the wastewater flows at high velocity through the sewer system to the central vacuum station. The ROEVAC ® system guarantees maximum operational safety with minimum energy costs. In some circumstances the vacuum sewers can be laid using trenchless technology or be placed above ground.

1. The Vacuum Station

All the vacuum sewers are connected to the vacuum collection vessel installed at the central vacuum station, where vacuum pumps create the required negative pressure (approx. – 0.6 bar). The vacuum vessel can be placed inside or buried outside the vacuum station. Transfer pumps convey the wastewater from the vessel to the wastewater treatment plant or to an existing sewer.
The capacity and dimensions of the vacuum station are dictated by the particular requirements of the sewer system. Operation of the vacuum and transfer pumps is controlled through a PLC with the ROEVAC ® software designed to ensure optimum demand-driven operation. A standard ‘compact vacuum station’ can be delivered prefabricated and tested for small sewer systems to service a small number of houses in villages or buildings on industrial estates. Individual design and construction services can be provided for vacuum stations for hundreds or thousands of houses and buildings.

2. The Collection Chamber

The water tight ROEVAC ® collection chamber is manufactured in PE-MD with three different designs available for the following loading conditions:

pedestrian loading
flood-proof and pedestrian loading
flood-proof and traffic loading up to 40t

In all designs the vacuum valve unit is kept separate from the wastewater sump ensuring the ROEVAC ® vacuum valve unit remains clean, dry and accessible.

Additional advantages of the ROEVAC ® chamber system are:

easily adapted on site to suit the level of house service drains and vacuum sewer pipes
no smell or deposits
no electrical power at the chamber
removable plug for connecting a suction lance enabling local emptying and easy cleaning
a stopper can be quickly installed to isolate the vacuum sewer for valve maintenance

3. Vacuum Valve Units

The valve unit, which works pneumatically, consists of the vacuum valve (diaphragm type) and it’s associated controller. ROEVAC ® vacuum valves are all-purpose, easy to maintain valves with a long design life. There are two types of units: the 50mm dia unit is normally installed, but where flow rates are high, e.g. restaurants, hotels and public buildings, the 65mm dia unit is recommended.
The ROEVAC ® pinch valve was developed for special applications in non-European countries. Its robust construction and 75mm dia. clear flow path makes it particularly suitable for high flow rates and wastewater with high solids content.
ROEVAC ® vacuum valves do not require electrical connections. The valves are activated pneumatically by rising water level in the collection sump. The function of the ROEVAC ® controller is to open the vacuum valve when the level of wastewater in the sump of the collection chamber is rising, and to close the valve after the batch volume and a preset amount of air has been evacuated from the sump. Valve opening times and air-liquid flow rates can be adjusted optionally by the controller. Roediger can also offer a sump and valve monitoring system that includes the street name and house number.

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