Custom
Purification System
Minimises Downtime
For Thames Water
When Thames Water was looking for a system to remove impurities from
anaerobic digester gases, it needed a system that would meet the stringent
clean up requirements and achieve zero plant shut down when carrying out
routine vessel maintenance.
The solution came in the form of a bespoke
Activated Carbon Vessel System that was
designed and supplied by Thermtech.
Removing impurities from waste water
Providing the population with clean
drinking water is a dirty job. Many
processes need to be implemented to
remove impurities from waste water.
These processes need to meet stringent
compliance regulations to guarantee the
production of safe drinking water. One of
these processes uses anaerobic digestion,
the by-product of which is biogas. The
biogas can be used as a valuable source of
fuel, provided it is "sweetened" by removal
of the trace amount of contaminants it
contains.
Delivering modern filtration
Activated carbon granules or pellets are
used for the removal of hydrogen sulphide
(H2S) in biogas streams generated from
various sources such as landfills, anaerobic
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digesters or, as in this application,
municipal wastewater treatment plants.
A granular form of activated carbon, a
material containing highly porous carbon
particles, is stored in specially designed
vessels. When a biogas stream is passed
through the vessel, H2S and other
impurities such as siloxanes are removed.
Having recently designed and built two
smaller systems to achieve H2S removal
for another UK water company, ThermTech
was again approached by CC Jensen, a
major project management contractor to
the water industry. ThermTech was asked
to provide a more complex activated
carbon system than previously supplied,
with several additional challenges. The
system would comprise three activated
carbon vessels including all pipe work and
control valves manufactured in stainless
steel. The supporting structure including a
complete skid unit was supplied, enabling
easy assembly and mounting of the
supplied equipment on site during the
installation process.
The end client, Thames Water, specified
a need to select any combination of gas
flow routes to any, or all, of the vessels and
for each vessel to have the facility to be
independently disconnected and taken
off-line for purging and maintenance while
the plant continues operation. In this way,
routine maintenance could be completed
without affecting plant efficiency.
The Solution
ThermTech designs and manufactures
these activated carbon vessels, offering a
range of standardised volumes as well as
custom designed units. In this application,
standard vessels with a volume of 4 m3
met the purification and gas flow capacity
requirements set out by Thames Water.
Close liaison was established with CC
Jensen and the initial system concept
agreed based on providing a modular style
design to simplify both site installation
and planned maintenance when the
plant is operational. Each design stage