Research Driven by Regulatory Needs: Metals and Nutrients in Aquatic Systems
THURSDAY, OCTOBER 25, 2012 - 3:30 PM IN B2, 350 AT THE UNIVERSITY OF WATERLOO
Abstract:
Metals
and
nutrients
can
have
potential
negative
environmental
impacts
if
discharged
at
sufficient
concentrations.
Environmental
legislation
attempts
to
determine
allowable
effluent
concentrations
for
appropriate
protection
of
receiving
waters.
Determination
of
these
values
is
an
on-going
challenge
and
research
sponsored
by
governments,
as
well
as
industry,
is
moving
towards
improved
regulatory
criteria
based
on
sound
multi-disciplinary
science.
For
this
talk,
research
will
be
presented
in
two
parts
(1)
phosphorus
removal
in
wastewater
treatment
(2)
speciation
dependence
of
metal
toxicity.
The
regulatory
driver
for
phosphorus
removal
research
is
a
trend
towards
lower
permit
limits
for
wastewater
treatment
plants,
especially
those
discharging
into
near-pristine
environments.
These
low
phosphorus
limits
have
required
wastewater
engineers
to
re-evaluate
how
phosphorus
is
removed
during
wastewater
treatment.
Treatment
plant
design
in
the
past
has
assumed
that
phosphorus
removal
occurred
via
precipitation
of
ferric
phosphate
but
research
at
Laurier
has
shown
that
the
mechanism
of
phosphorus
removal
is
via
surface
complexation
to
hydrous
ferric
oxide
particles.
This
different
mechanism
has
implications
for
how
the
wastewater
industry
moves
forward
in
developing
new
removal
technologies
and
improving
existing
practices.
A
regulatory
driver
for
metal
speciation
research
is
a
large
data-gap
in
chemistry
and
toxicology
of
metals,
such
as
copper,
in
marine
systems.
For
freshwater
systems,
a
regulatory
tool
exists
call
the
biotic
ligand
model
(BLM).
The
BLM
allows
for
computer
simulated
toxicity
testing
which
takes
into
account
site-specific
water
quality
parameters.
This
allows
for
regulations
to
reflect
that
some
waters
are
more
sensitive
than
other
waters
in
terms
of
potential
metal
impacts.
Research
will
be
presented
towards
the
development
of
a
saltwater
BLM
with
an
emphasis
on
electrochemical
and
spectroscopic
methods
to
determine
copper
speciation.