Vacuum Sewage
Collection System
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Conventional gravity sewage collection system works just fine in many situations, particularly in areas with a large population equivalent, or low water tables. However, in areas where population equivalent are small, the terrain is flat or rocky, the soil condition is unstable, the groundwater table is high, or houses built on stilts, the vacuum sewage collection system is a technically and economically feasible alternative.
Envitech is the leading and largest vacuum sewage collection system provider in Malaysia and Brunei with more than 20 years’ expertise and positive track records. We infuse our work with a deep passion for pushing boundaries and delivering best engineering practices.
As the name implies, vacuum sewer relies on a vacuum created at a central collection station to have sewage transported from its sources to receiving sewage treatment plant for treatment.
Operation Of Vacuum Sewage Collection System
The following illustrations shows the sequencing of how a batch of sewage is evacuated in Redivac Vacuum Sewage Collection System.
Chamber receives sewage
from households
Sewage builds up
in Chamber
Vacuum Interface
Valve opened
batch of 40lit
Sewage evacuated
There is no electrical component at the individual connections to the vacuum sewers. The vacuum system designs do not require any special plumbing inside the house or building.
Depending on layout, a collection chamber can serve up to six houses. Sewage from a household is first collected in a service connection manhole, and is subsequently drained via a gravity lateral sewer into the wet sump of a collection chamber that is isolated from the main vacuum line by a vacuum interface valve. As the level of the sewage within the wet sump rises, air is trapped in a pipe called a ‘sensor pipe’, the pressure of which increases as the sewage level continues to rise.
When a predetermined volume of sewage collects in the chamber, the sensor pipe prompts a pneumatic switch of the interface unit to operate, thus allowing the interface valve to open. The sewage is propelled by a pressure difference between the air admitted through the valve and the vacuum in the sewer. This results in a slug of sewage being forced rapidly through the main.
Advantages Of Vacuum Sewage Collection System
Vacuum sewers have a lot to offer. Its advantages include but not limited to: small bore pipes, much reduced dewatering, minimum disruption, fast installation, reduced reinstatement, very versatile, no manholes for change of direction or gradient, no ingress means low treatment cost, no egress means no contamination, and phased installation possible.
Other distinctive advantages: environmental impacts of the installation works are negligible; pipes and chambers for water villas can be carefully located for minimum exposure, and no low-hanging pipes means boats can get pass underside the walkways.
Vacuum System
Installation Works
- Shallow trench 1m deep
- Small bore PE pipe
- Light duty excavation equipment
- Minimal backfill & reinstatement costs
Gravity System
Installation Works
- Expensive excavation & backfill costs
- Deep trench
- Heavy large diameter pipes
- Heavy excavation and lifting plant
Design Flexibility
- Layout flexibility
- Accommodates obstructions without difficulty
- Can flow uphill & around obstacles
- No manhole required
Design Flexibility
- Rigid constraints on line & level
- Re-routing required to avoid existing utilities
- Only flows downhill
- Manholes required
Operation Works
- Watertight welded polyethylene joint
- Flexible pipe – no cracking
- No ex filtration
- No infiltration
Operation Works
- Leaking joints & cracks
- Conventional rigid pipes susceptible to cracking
- Exfiltration of contaminated sewage
- Infiltration of water requires costly treatment
Maintenance Works
- No blockages due to 6m/s flow
- Self cleansing vacuum sewer
Maintenance Works
- Blockages due to low gradients
- Continual maintenance requirement to sewers
Applications Of Vacuum Sewage Collection System
There are various situations where a vacuum sewerage system can be used. A few typical applications for this flexible and environmentally friendly technology are listed below.
Rocky Terrain
Narrow Access
Resorts
High Water Table
Flat & Waterlogged Area
Water Villages
Water Villas
A village Separated by a River
Redivac Vacuum Interface Valve
Redivac Vacuum Interface Valve has satisfied the requirements set out in the British Standard document BS EN 16932-3:2018 entitled “Drain and Sewer Systems Outside Buildings – Pumping System”. Redivac Vacuum Interface Valve was tested as described in Clause 12.2 and Annex B.1.3, B.1.4 & B.1.5. Below are some of the photos taken during the tests.
Testing Rig
259,095 cycles undertaken
Blockage Test
Submergence Test
The independent Messrs. Standardmark Laboratory Sdn. Bhd witnessed the testing of Redivac Vacuum Interface Valve, and upon completing the tests as specified above, the valve was certified. Please click here complete test report.