About Gravity Sewage Disposal
One of the oldest and well known gravity sewerage system is the Roman Cloaca Maxima was built 2500 years ago.
Till the end of the 19th Century this technology was the only way to carry out canalization.
(This technology was the only way to carry out canalization till the end of the 19th Century.)
Gravity drainage system provides a natural solution on sloping landscapes for sewage disposal and the only thing we have to do is to follow the slopes with a not deeply laid pipe system.
Side effects of Gravity Waste Water Drainage System
Gravity-based pipe network is built with 0,5 per cent slope angle. Pipeline starts from 2 meters depth and on vertical surface after 1 kilometre laid it goes further down to 7 meters with a good chance to get under the ground-water where beside installation difficulties (like timbering, insetting ground-water level, large-scale ground works, risk of post compaction, high volumen of road stats, etc) we still have to face serious operational problems as well (like ground-water infiltration, systematic high pressure washing, regular lift overs and repair difficulties).
In order to reduce installation depth large number of pipes have to be built in as well.
This procedure in addition to causes lot of assembly difficulties and very hard to eliminate odor effects it also requires high operating costs as well.
History of the Vacuum Sewage Disposal System
In the second part of the 19th Century people realized that high speed airflow generated in closed pipe system is able to whirl and deliver material with itself.
Predecessor of the modern vacuum sewage draining systems had appeared at the end of the 19th century.
Vacuum sewage disposal has been patented first time in The Netherlands in 1870s.
Why is it worth to build waste water drainage systems with the help of vacuum technology ?
In general 3-5m
Flexibility of trail management
can goes upwards, bypassing blockages (barriers ?)
rollway shaft needed in case of barrier
Pipe materials and couplings
Socket joints and crackings can leak
Application of Vacuum Sewage Disposal
Vacuum sewage disposal system is an ECO friendly solution where investment costs on lowlands can be 40 per cent less comparing to gravity system’s. Operational cost of vacuum system is also favorable and it can be installed due to extreme terrain conditions too.
Mainly recommended application fields are :
– lowlands settlements
– places where ground-water level is high, places with rocky or loose soil structure
– narrow streets, solid pavement , in case of utilisaties saturation
– one direction extending or loose-mounted settlements
– river or lake side communities
– waste water
– hardly approachable places
– petrochemical industry
– drainage of internal water
Not recommended application areas are :
– hilly, mountanious places
Comparison of investment benefits :
Vacuum licquid collecting system has several advantages comparing to the traditional gravity solution where trench depth and large number of pumps make system installation and application much more expensive.
Vacuum System :
– small trench depth (approx. 1m)
– small-diameter PE pipes
– light trencher machines
– minimal repair costs
– flexibility of installion track
– accomodate to terrain conditions
– also well operating on uphills
– no need to use cleaning tunnels
Gravity System :
– deep, wide trench
– big-diameter pipes
– heavy duty bulky machines
– higher repair costs
– limited installation tracking
– highly depends on terrain conditions
– only operates in valley direction
– cleaning tunnels needed
Comparing Operational Benefits :
– watertight welded connections
– flexible PE pipes, do not break
– no leakage
– no infiltration
– thankful to the 6 m/sec flow rate it operates without any pluggings
– self-cleaning, low maintenance repair needed
– operates without any pumps
– danger of socket leaking
– rigid pipes, danger of breakage
– possibility of sewage leakage
– possibility of ground-water infiltration
– because of small gradient it tends to sediment, pluggings
– has to be cleaned regularly
– operates with pumps