Water & Wastewater Asia March/April 2024

FOCUS
Chemical dosing solutions
for a newly built
sewage plant
1 2
During construction of a sewage plant in
Sichuan, China, the operator required a
dosing pump control system in order to
precisely manage chemical injection as
part of the site’s design. The plant — a
US$11m development expected to process
20,000m³ of sewage per day — was to
incorporate advanced technology for the
handling of complex applications such as
Anaerobic–Anoxic–Oxic (AAO), including a
deep bed denitrification filter.
Meanwhile, a key requirement during
planning was the protection of water
quality and the maintenance of a healthy
ecological balance within local water
bodies. For this, chemical metering
pumps specialist SEKO was approached
to supply a solution for sodium
hypochlorite, phosphate remover and
carbon-source dosing at various stages
of the process. Following an initial site
assessment and collaboration with
the operator, SEKO recommended its
motor-driven Spring series pumps and
Elektra control units as the solution to
meet the operator’s needs.
24/7 DATA ON DEMAND
With a requirement for high-accuracy
dosing to ensure reliable water treatment
and reduced chemical consumption, Spring
and Elektra’s precision to within 2% of
target made the combination the natural
choice. Meanwhile, Elektra’s integrated
wifi server and connection to the SekoWeb
smartphone app and online platform meant
that technicians could view live and historical
dosing data on demand 24/7 from any
location.
With this information at their fingertips, they
would gain an understanding of their process
while the ability to manage programmes and
view alarms remotely. This allowed them to
implement changes, identify faults and plan
maintenance without the need to attend
site. Not only would this enable the operator
to save on travel time and cost, it meant
they could also reduce their environmental
impact as part of a long-term sustainability
policy. Elektra also boasts a Modbus RS485
protocol integrated on the mainboard, giving
the operator another data communication
option should wifi connection be unavailable.
1 SEKO recommended its motor-driven Spring series
pumps and Elektra control units as the solution to
meet the operator’s needs (Image: SEKO)
2 The operator saved on travel time and cost, and
they could also reduce their environmental impact
(Image: SEKO)
ELEKTRA AND SPRING SERIES
The combination of Spring — with a flow rate
of 5.5-1,200L/hr and a maximum pressure
of 16bar — and Elektra — with a flow rate of
1.5-1,000L/hr and a maximum pressure of
20bar — provides the client with real-time
flow monitoring and control, ensuring that
chemical dosing remains stable throughout
operation; a valuable feature in a process
where consistency is essential.
Finally, with 4-20mA analogue output,
Elektra is both noise-resistant and well-suited
for long-distance transmission in this
large-scale site. Since the installation of
SEKO’s Spring and Elektra systems, the
operator has reported excellent control of their
process and a water quality improvement in
surrounding watercourses.
38 Water & Wastewater Asia | March-April 2024