Water & Wastewater Asia September/October 2019

26 | INSIGHT
A wastewater plant in Southern Europe
succeeded in achieving annual polymer
savings of 33.8 per cent in the belt thickening
stage as well as 16 per cent polymer savings
in centrifuge dewatering. The referenced
plant in Southern Europe also cut down on
another, often scarce resource – the need for
supervision by a qualified operator.
TIME IS MONEY – CONSIDER
MAINTENANCE AS WELL AS
OPERATOR PRESENCE
Operators are among a plant’s most
important resources, and the more complex
a plant becomes the harder it is to find
staff who are suitably qualified to always
keep an eye on the most important process
parameters, evaluate them, and take the
right steps to keep process performance at
the required level. With equipment that needs
to be monitored and adjusted constantly,
plants become more and more dependent
on selected operators who need to be in
more than one place at the same time.
In thickening, the gravity belt table shines
with its performance: Maintenance is easy
and inexpensive, especially as ANDRITZ has
simplified the cleaning process by installing
manually or automatically operated internal
brushes to clean clogged nozzles. For
dewatering, the belt press, the filter press,
and the screw press have proven to be very
practical as they have a simple mechanical
design compared to more complex systems
like the decanter centrifuge and require
only low to average mechanical skills for
maintenance, which is also reflected in spare
part costs.
Maintenance intensity, complexity, and
costs go hand-in-hand. The worst-casescenario
would arise from choosing a
high-maintenance machine from a supplier
without local service technicians available,
thus lengthening the duration of a shutdown
in case of a malfunction. This is why
checking the suppliers’ service network
Water & Wastewater Asia • September / October 2019