Water & Wastewater Asia March/April 2022

ENVIRONMENTAL REPORT
Environment Agency to use widely, especially
at potentially high-risk locations such as
sewage treatment works.”
The Centre of Hydrology and Ecology
concurred: “The use of multi-probe Sondes
with telemetry to detect ammonium, turbidity
and dissolved oxygen concentrations in
effluents at hourly frequencies, alongside flow
gauging, could provide an accurate estimate
of pollution loadings coming from sewage
treatment works, an early warning system
to detect sewage treatment works failures
and provide the key data for researchers
to evaluate the impact of combined sewer
overflows on downstream river water quality
and ecology.”
The report provided further evidence in
support of continuous monitoring. For
example, it said continuous monitoring
could provide a high level of certainty as
to the condition of a river and the causes
of pollution, thus alleviating the need to
apply complex statistical processes to data
analysis. The technique could be costeffective
if used in a targeted way. It was
suggested that if there is a particular problem
to investigate, the agency can find out more
from continuous monitoring in two weeks
than they would probably find in many, many
years of random sampling.
Salmon and Trout Conservation also
recommended the use of continuous
monitoring, especially with the ‘spikey’
nature of discharges from such industries
as watercress and trout farming. It said that
the technology has progressed so markedly
that continuous monitoring should now
be both practical and affordable for the
Environment Agency to use widely, especially
for potentially high-risk polluters such as
sewage treatment works. In addition, the
report said that the Environment Agency, in
its submission, had said that it would like
to explore the use of continuous monitors
for the quality of effluent that could “trigger
early warning if effluents were starting to
deteriorate” for regulatory purposes.
Meteor Communications’ Environmental Sensor Network (ESNET)
During his presentation to the EAC, Scott which enables the measurement of other
explained that remote, continuous river water pollutants such as pharmaceuticals and
quality monitoring technology is already plastics. Autosamplers can collect at preset
intervals or when initiated by specific
well-proven, and he elaborated: “Over 300 of
our Environmental Sensor Network (ESNET) alarm conditions. Meteor Communications
outstations are currently monitoring UK stressed this is a particular advantage for
rivers, but many more will be necessary in the water companies and regulators because it
future because, for example, there are over enables the immediate collection of samples
6,000 sewage treatment works in England in response to a pollution incident, which
alone.
informs mitigation measures and helps to
identify the source of contamination.
“The current ESNET users are the
Environment Agency, seven water
The ESNET systems were designed for the
companies, environmental consultancies and collection of real-time data from remote
other water sector bodies. ESNET produces locations because they operate on low power
scientifically robust, legally enforceable and wirelessly connect with the MeteorCloud
evidence that truly reflects the dynamic web portal providing secure access for
nature of the surface water environment. viewing and downloading data.
It differentiates and identifies sources of
pollutants from man-made activity such as Summarising, Scott said: “The EAC Report
sewage treatment works, combined sewer provides a detailed plan for improving water
overflows and agriculture; outputting highresolution
data for the most important water this will require a significant investment
quality in our rivers, but as the report says,
quality parameters.”
in infrastructure. A relatively small part of
that investment, we believe, should be in a
The ESNET systems typically monitor
much higher number of remote continuous
parameters such as dissolved oxygen,
water quality monitoring systems. This will
temperature, pH, conductivity, turbidity, significantly improve our understanding of
ammonium, Blue Green Algae and
pollution, enable rapid response to pollution
chlorophyll. However, it is also possible to incidents, and allow source attribution
include other water quality parameters as when such events occur. It is therefore very
well as remote cameras, water level and pleasing to note that the report recommends
flow, or meteorological measurements. that the Environment Agency should rapidly
The addition of autosamplers enables the introduce cost-efficient and effective sensors
collection of samples for laboratory analysis, at an increased number of locations.”
WATER & WASTEWATER ASIA | MARCH/APRIL 2022 23