Introduction to Alternatives to Gate Valves in Stormwater and Wastewater

Stormwater and wastewater (sewage) systems can be built as separate
or combined facilities. The more modern houses and businesses now have
separate piping systems for sewage and stormwater, while some cities are
upgrading their present combined systems due to the occurrences of
spillage of sewage into the environment following a rainstorm. This
spillage can be from overflow at the wastewater plant or from regulators
in the piping system, but both measures involve dumping raw sewage into
the local environment.
This happens because of a combined plant’s inability to process the
additional stormwater and sewage at the same time, preventing a
back-flow of sewage to the local houses.

This is an article on flow control of drainage from wastewater and
stormwater systems, in particular from combined sewage systems. We begin
with a look at the some of the problems with a combined sewage plant
and then move on to the control of outflow.
As we have seen the combined wastewater and stormwater plants are
being phased out in favor of a separate plant for each process, however
many major cities of the developed world do still use this system. This
is mainly because sewage and stormwater collection in the same piping
system was acceptable in the early 1900’s. However, as the city
populations increased, the sewage plants could not handle both sewage
and stormwater drainage, and thus we have the current problem of
controlling the inflow, processing, and outflow from a combined sewage
processing plant.
To overcome the problem of sewage overflow from current plants, some
plants install large underground storage tanks to hold the influx of
stormwater and sewage, which is then processed later. Tunnels at the
gate valve facility have also been used to store and treat drain water and sewage influx following rainstorms.
In order to have separate processing facilities, the stormwater and
wastewater must be collected by two separate systems; one for sewage and
grey water,
and one for rainwater drains. In most cities with combined sewer
systems, it is difficult to convert to separate systems, but many cities
in the US and Europe are converting a little at a time.
In the developing countries, there is little effort to treat sewage.
80-90% of sewage is pumped directly into rivers, lakes, or the sea; the
majority of Sub-Sahara countries are without any sewage processing
facilities.
From the originalgatevalve
.