Water Safety Plan
Guide
Treatment Processes
– Iron and Manganese Removal
Version 1, Ref P8.2
January 2014
Citation: Ministry of Health. 2014. Water Safety Plan Guide:
Treatment Processes – Iron and Manganese Removal, Version 1, ref
p8.2. Wellington: Ministry of Health.
Published in January 2014
by the Ministry of Health
PO Box 5013, Wellington, New Zealand
ISBN: 978-0-478-42750-9 (print)
ISBN: 978-0-478-42751-6 (online)
Previously published in 2002 as Public Health Risk Management
Plan Guide: Treatment Processes – Iron and Manganese Removal,
Version 1, ref p8.2. This publication’s title and any reference within
the text to ‘public health risk management plan’ were changed in
January 2014 to reflect the December 2013 legislation change of the
term ‘public health risk management plan’ to ‘water safety plan’. No
other changes have been made to this document.
This document is available at: www.health.govt.nz
This work is licensed under the Creative Commons Attribution 4.0 International
licence. In essence, you are free to: share ie, copy and redistribute the material in any medium or
format; adapt ie, remix, transform and build upon the material. You must give appropriate credit,
provide a link to the licence and indicate if changes were made.
Contents
Introduction
1
Risk Summary
3
Risk Information Table
4
Contingency Plans
12
Water Safety Plan Performance Assessment
14
Ref P8.2
Version 1, January 2014
Water Safety Plan Guide: Treatment
Processes – Iron and Manganese Removal
iii
Introduction
Iron and manganese are undesirable in water because of their effect on the appearance and
taste of the water, their ability to cause staining, and the health effects of manganese. They
can be removed by:

oxidising them to form particles in the water, then letting the particles settle, or filtering
them out of the water

adsorbing them onto ion-exchange resins.
Oxidation can be carried out by:

aeration
–
blowing air through the water
–
spraying the water in the air

using dissolved chemical oxidants
–
chlorine
–
chlorine dioxide
–
ozone
–
potassium permanganate (KMnO4)

(see Guide P7.1)
(see Guide P7.2)
(see Guide P7.3)
adsorbing the metals onto greensand.1
This Guide is mainly concerned with removal using potassium permanganate, aeration,
greensand and ion-exchange resins.
If an event occurs during the removal of these metals (ie, the process doesn’t work properly),
the following could happen:

if there is incomplete removal of manganese, the manganese may cause sickness

if too much oxidant is added, sickness may result from the oxidants themselves

if germs get into the water during aeration, these germs may cause sickness

if germs grow in the ion-exchange resin, these germs may cause sickness.
The use of chemicals during the removal process can present risks to the health of treatment
plant staff. These are acknowledged, but are not discussed further as such risks are the subject
of health and safety in employment legislation.
The success of removal by oxidation depends on:

the oxidant used – stronger oxidants, and higher oxidant concentrations give better
oxidation (see Guides P7.1, P7.2, P7.3)

pH – oxidation is faster at higher pH values (see Guide P8.1)

organic matter attached to the metal – this makes oxidation difficult.
1
A naturally-occurring mineral treated with manganese which assists in the oxidation of the metals.
Ref P8.2
Version 1, January 2014
Water Safety Plan Guide: Treatment
Processes – Iron and Manganese Removal
1
After oxidation, the process used to remove the insoluble metal compounds will affect how
well the metal is removed (see the appropriate Guides in the P5 series for
coagulation/flocculation and sedimentation, and in the P6 series for filtration).
Greensand filters can oxidise and filter the metals in one step. These filter beds need to be
treated with potassium permanganate either continuously or periodically, when the filter
stops removing the metals properly. The risk information contained in Guide P6.1 is also
helpful for operating greensand filters.
For the ion-exchange process to work, the metals must be in a dissolved form. Air and other
oxidants must therefore be kept out of the water until after it passes through the ion-exchange
unit.
2
Water Safety Plan Guide: Treatment
Processes – Iron and Manganese Removal
Ref P8.2
Version 1, January 2014
Risk Summary
The two events creating the greatest risk involved in the removal of iron and manganese from
water are adding too much oxidant to the water (see P8.2.2) and germs getting into the water
during aeration (see P8.2.1).
The most important preventive measures are:

monitor the process to be sure the right dose is used, regardless of how the quality of
the incoming water may change (see P8.2.2, P7.1.2.4 (chlorine) and P7.2.2.4 (chlorine
dioxide))

regularly maintain the dosing equipment (P8.2.2.3, P7.1.2.1 (chlorine) and P7.2.2.1
(chlorine dioxide))

place netting over aerator grills to stop entry of larger animals (P8.2.3.1).
(References in parentheses are to the Risk Information Table.)
Ref P8.2
Version 1, January 2014
Water Safety Plan Guide: Treatment
Processes – Iron and Manganese Removal
3
Risk Information Table
Reliable information about water quality is essential for the proper management of a water
supply. Knowledgeable and skilled staff are also essential for minimising the public health
risks associated with water supplies. Please read the staff training (Guide G1) and the
monitoring guides (Guide G2). While we haven’t pointed out every detail of how these
documents are linked with the present document, the links are many and are important.
Abbreviations: DWSNZ – Drinking-Water Standards for New Zealand; MAV – Maximum acceptable value – see
DWSNZ:2000
Causes
Preventive measures
Checking preventive measures
What to check
Corrective action
Signs that action is
needed
Removal by oxidation
Event: NOT ALL THE MANGANESE REMOVED
Possible hazards: Manganese
Level of risk: Low

P8.2.1.1
Treatment
option not right
for the water
chemistry.

P8.2.1.2
pH level is
unsatisfactory
for the water
chemistry.
Before designing the
treatment plant, use
bench-scale and pilotscale tests to select the
best treatment for the
water chemistry.

Before designing the

treatment plant, use
bench-scale and pilotscale tests to determine
the best pH level for the
treatment option in use.
Manganese.
Manganese.

Manganese

concentration is
more than 50% of
the MAV.

No sign of
insoluble
manganese
formation directly
after oxidation
(metals must be
insoluble to be
removed).

Manganese

concentration is
more than 50% of
the MAV.

No sign of
insoluble
manganese
formation directly
after oxidation
(metals must be
insoluble to be
removed).
Carry out tests
to identify a
more
appropriate
treatment for
the water.
Monitor the
manganese
concentration
while adjusting
the pH to
determine the
best pH level.
P8.2.1.3
A number of oxidants can be used for the precipitation of iron and manganese. In addition to the causes of
incomplete oxidation noted in P8.2.1.1 and P8.2.1.2, another possible cause is that the oxidant concentration
is too low. For oxidation by chlorine, chlorine dioxide or ozone, refer to the event of oxidant concentration too
low in Guides P7.1 (chlorine), P7.2 (chlorine dioxide) or P7.3 (ozone). In all cases, manganese should be
added to the list of determinands to monitor, especially when determining the correct dosing set-point
(dose rate), and the indicators noted above should also be included.
4
Water Safety Plan Guide: Treatment
Processes – Iron and Manganese Removal
Ref P8.2
Version 1, January 2014
Causes
Preventive measures
Checking preventive measures
What to check
Corrective action
Signs that action is
needed
Event: NOT ALL THE MANGANESE REMOVED cont’d
The possible causes and preventive measures etc., of incomplete oxidation by potassium permanganate
(KMnO4), aeration and greensand filtration are covered below.
P8.2.1.4

KMnO4/air dose
set-point
incorrect/ dose
calculation
incorrect.

P8.2.1.5
KMnO4/air
supply
exhausted.
From time to time have
a second person check
the dose calculations.

Regular manual checks 
on controller calibration.




Manganese.

Manganese

concentration is
more than 50% of
the MAV.

No sign of
insoluble
manganese
formation directly
after oxidation
(metals must be
insoluble to be
removed).
Use a dose controller
(eg, reduction-oxidation
controller) that will take
account of changes in
water chemistry, or
monitor the manganese
concentration often
enough so that changes
in water chemistry can
be matched.

Dosing
controller
incorrectly
calibrated.
P8.2.1.6

Use bench-scale and
pilot-scale tests to
determine the best
KMnO4 dose or
aeration rate.
Install an alarm to warn 
when the KMnO4 supply

is running low.
Ensure a reserve supply
of KMnO4 is kept on
site.
Keep records of oxidant
use to provide a guide
to the length of time the
chemical supply is likely
to last.
Manganese.
Manganese.


Manganese

concentration is
more than 50% of

the MAV.

No sign of
insoluble
manganese
formation directly
after oxidation
(metals must be
insoluble to be
removed).

Calibration
schedule not
signed off.

Manganese

concentration is
more than 50% of

the MAV.
Maintenance
log.

No sign of
insoluble
manganese
formation directly
after oxidation
(metals must be
insoluble to be
removed).
Carry out
manual checks
on manganese
removal and
adjust oxidant
dose
accordingly.
Start calculation
checks.
Recalibrate
controller.
Increase
oxidant dose
rate until
recalibration
can be
undertaken.
Install alarm
system.
Urgently order
replacement
chemicals.

Start log of
oxidant use.

Initiate pump
maintenance
programme.
Schedule a preventive
maintenance
programme for air
pumps.
Ref P8.2
Version 1, January 2014
Water Safety Plan Guide: Treatment
Processes – Iron and Manganese Removal
5
Causes
Preventive measures
Checking preventive measures
What to check
Corrective action
Signs that action is
needed
Event: NOT ALL THE MANGANESE REMOVED cont’d

P8.2.1.7
KMnO4 supply
adequate, but
KMnO4 is not
being dosed
into the water:
–
Dosing
pump
failure
–
Feedlines
blocked.
Routine maintenance of 
dosing pumps and

feedlines to ensure they
are not blocked (see
Guide P10).
P8.2.1.8

Dose controller
malfunction.
Do routine controller
maintenance.

Replace controller with
a reliable unit if the
present unit is suspect.
Manganese.

Maintenance
log.


Manganese.

Maintenance
log.

Maintenance log
shows ongoing
problems with
pump or line
blockage.

Manganese

concentration is
more than 50% of
the MAV.

No sign of
insoluble
manganese
formation directly
after oxidation
(metals must be
insoluble to be
removed).


6
Water Safety Plan Guide: Treatment
Processes – Iron and Manganese Removal
Manganese

concentration is
more than 50% of
the MAV.

No sign of
insoluble
manganese
formation directly
after oxidation
(metals must be
insoluble to be
removed).
Identify cause
of fault and
rectify.
Determine what
steps can be
taken to stop it
happening
again.
Identify cause
of fault and
rectify.
Replace
controller with a
new unit.
Maintenance log
shows frequent
maintenance
needed.
Ref P8.2
Version 1, January 2014
Causes
Preventive measures
Checking preventive measures
What to check
Corrective action
Signs that action is
needed
Event: NOT ALL THE MANGANESE REMOVED cont’d
P8.2.1.9
KMnO4 dosing
solution
concentration
incorrect, or
prepared with
incorrect
chemical.




P8.2.1.10

Poor air
circulation for
droplet, or thinfilm, aerator.
P8.2.1.11
Poor nozzle
design in spray
aerator.

From time to time have
a second person check
calculations used for
preparation of KMnO4
dosing solution.
Check KMnO4
concentration in each
new batch of dosing
solution prepared.

Manganese.

Permanganate
concentration
in dosing
solution.


Manganese

concentration is
more than 50% of
the MAV.

No sign of
insoluble
manganese
formation directly
after oxidation
(metals must be
insoluble to be
removed).
Supplier’s
certification of
analysis.
Ensure that chemicals
are delivered to the
correct bin, that bins are
labelled, and that an
operator is there to
supervise chemical
delivery.

Checks show
frequent incorrect
calculations.

Provide for staff
additional
training in
calculations for
solution
preparation.

Ensure that
chemical
supplier is
aware of the
need for the
operator to be
present when
chemicals are
delivered.

Obtain a new
batch of
chemical from
the supplier, if
quality
unsatisfactory.
Check quality of KMnO4
delivered.

Do calculations and
tests during design to
ensure air circulation
will allow enough
oxygen to dissolve in
the water.
Design to ensure
droplets are given
longest possible time in
the air to allow oxygen
exchange (nozzle
design and trajectory
are important).
Ref P8.2
Version 1, January 2014

Manganese.
Manganese.

Manganese

concentration is
more than 50% of
the MAV.

No sign of
insoluble
manganese
formation directly
after oxidation
(metals must be
insoluble to be
removed).


Calculations show
air circulation too
low.

Manganese

concentration is
more than 50% of

the MAV.

Re-calculate
chemical
quantities
required for the
dosing solution,
and prepare a
new solution.
If aerator relies
on natural draft,
consider
installation of
blowers to
provide forced
draft.
Modify the
aerator to
minimise
obstructions to
air flow.
Replace
nozzles.
Modify spray
trajectory.
No sign of
insoluble
manganese
formation directly
after oxidation
(metals must be
insoluble to be
removed).
Water Safety Plan Guide: Treatment
Processes – Iron and Manganese Removal
7
Causes
Preventive measures
Checking preventive measures
What to check
Corrective action
Signs that action is
needed
Event: NOT ALL THE MANGANESE REMOVED cont’d

P8.2.1.12
Poor design of
aerator.
During design do pilot
trials to check that the
type of aerator chosen,
and its design, will
provide adequate
oxidation of the metals.

Manganese.

Manganese

concentration is
more than 50% of
the MAV.

No sign of
insoluble
manganese
formation directly
after oxidation
(metals must be
insoluble to be
removed).

Trials/calculations
show design is
unsatisfactory.
Replace or
modify the
aerator.
P8.2.1.13
See P6 Guide series for a discussion of events, causes, preventive measures etc. associated
with the use of standard filters, and those using greensand for combined oxidation and
Poor removal of
filtration.
precipitated
metal by
filtration.

P8.2.1.14
Greensand
performance
inadequate.

P8.2.1.15
Power failure.
Ensure KMnO4 dose (in 
the influent, or in off-line
regeneration) is
adequate to maintain
the oxidising capacity of
the bed.
Manganese.


Ensure that
concentrations of other
chemically reduced
determinands in the
water (eg, organic
matter, nitrite, ammonia
and hydrogen sulphide)
are not so high that they
exhaust the bed’s
oxidising capacity.

Provide sufficient time
for the bed to “ripen”
after bringing it back online.

Schedule routine filter
maintenance. This
should check for
channelling for example
(see also Guide P6.1).

Provide stand-by
generator to ensure
continuity of power.

Continuity of
power.

Manganese

concentration is
more than 50% of

the MAV.
No sign of
insoluble
manganese
formation directly
after oxidation
(metals must be
insoluble to be
removed).
Loss of power.
Adjust dose
rate.
Undertake a
more complete
check on the
water chemistry
and reconsider
this treatment
option if
reduced
determinand
concentrations
are high.

Modify
operational
procedure.

Start a filter
maintenance
programme.

Refuel
generator, if
appropriate.
Event: OXIDANT DOSE TOO HIGH
Possible hazards: Manganese (if KMnO4 used as an oxidant), chlorine, chlorine dioxide or KMnO4.
Level of risk: Moderate
P8.2.2.1
Possible causes of overdosing with chlorine and chlorine dioxide are discussed in the relevant Guides for the
individual oxidants. See Guides P7.1 (chlorine) and P7.2 (chlorine dioxide). Overdosing with ozone will not
create a public health risk because of the rapid decay of this oxidant. The causes and preventive measures etc.
associated with the use of KMnO4 as an oxidant are noted below.
8
Water Safety Plan Guide: Treatment
Processes – Iron and Manganese Removal
Ref P8.2
Version 1, January 2014
Causes
Preventive measures
Checking preventive measures
What to check
P8.2.2.2
KMnO4 dose
rate set
incorrectly or
incorrect dose
calculation.
P8.2.2.3
Dosing
controller
malfunction.
P8.2.2.4


Do bench-scale and

pilot-scale testing to

determine the best
KMnO4 dose or aeration
rate.
From time to time get a
second person to
checks on the dose
calculation.

Routine controller
maintenance.

Dosing
controller
incorrectly
calibrated.
Signs that action is
needed

Manganese

concentration
more than 50% of
its MAV.

Pink water.
KMnO4 dose.
Use a controller
(oxidation –reduction
potential) that will
automatically adjust the
dose rate to ensure the
right oxidant dose is
used, or monitor often
enough that the oxidant
dose can be adjusted to
match changes in water
chemistry.


Manganese.


KMnO4 dose.

Maintenance
log.
Replacement of a
suspect controller with a
reliable unit.
Regular manual checks
on the controller’s
calibration.
Corrective action



KMnO4 dose.
Manganese

concentration
more than 50% of
its MAV.

Pink water.

Maintenance log
shows frequent
maintenance
needed.

Maintenance log
not signed off.

Manganese

concentration
more than 50% of

its MAV.

Pink water.

Calibration
schedule not
signed off.
KMnO4 dose.

KMnO4
concentration
in the dosing
solution.
Manganese

concentration
more than 50% of
its MAV.

Pink water.

KMnO4
concentration in
the dosing
solution above the
level expected.
Carry out
manual checks
on manganese
concentration
and adjust the
oxidant dose
accordingly.
Start checks on
the dose
calculations.
Identify cause
of fault and
rectify.
Replace
controller with
new unit.
Recalibrate
controller.
Decrease dose
rate until
recalibration.
Event: OXIDANT DOSE TOO HIGH cont’d
P8.2.2.5
KMnO4 dosing
solution
concentration
too high.


Check the concentration 
of the KMnO4 dosing

solution when it is first
prepared.
Separate chemical
storage from dosing
solution preparation
tanks to reduce the
likelihood of chemical
spillage into the tanks.
Ref P8.2
Version 1, January 2014
Determine the
cause of the
high KMnO4
concentration
and rectify.

Provide training
in the
preparation of
oxidant
solutions
(including
calculations).

Identify the
reasons for any
spillage and
rectify if
possible.
Water Safety Plan Guide: Treatment
Processes – Iron and Manganese Removal
9
Causes
Preventive measures
Checking preventive measures
What to check
Corrective action
Signs that action is
needed
Event: GERMS INTRODUCED DURING AERATION
Possible hazards: Germs.
Level of risk: Moderate1

P8.2.3.1
Microorganisms
introduced into
the water during 
aeration, either
in the airstream
or through
animals
entering the
aerator.
1
Place netting over
aerator grills to stop
entry of larger animals
(eg, birds, rats, etc).

Microbiological
water quality.

E. coli or
coliforms
detected in a
100 ml sample
taken after the
aerator.
Provide disinfection
following aeration to
inactivate germs that
get into the water.

Disinfection of
the water
following
aeration.
The consequences of the event, and therefore the level of risk, will be influenced by how well following
disinfection processes works.
Causes
Preventive measures
Checking preventive measures
What to check
Corrective action
Signs that action
is needed
Removal by ion exchange
Event: INCOMPLETE REMOVAL OF MANGANESE
Possible hazards: Manganese.
Level of risk: Low
P8.2.4.1

Check water chemistry

before selecting the
treatment option to
determine the
concentrations of ions that
will be adsorbed by the
resin (commonly iron,
manganese, calcium and
magnesium). This will allow
an estimate of operational
time before regeneration will
be required, and how much
the hardness of the water
will interfere with the iron
and manganese removal.

Monitor changes in treated
water chemistry (eg,
calcium, manganese) to
determine when the resin is
exhausted and regeneration
is required.
Ion-exchange
resin
exhausted.
10
Manganese.
Water Safety Plan Guide: Treatment
Processes – Iron and Manganese Removal

Manganese
concentration
more than
50% of its
MAV.

Consider a
different
treatment
process.
Ref P8.2
Version 1, January 2014
Causes
Preventive measures
Checking preventive measures
What to check
P8.2.4.2

Ion-exchange
resin is
fouled.

P8.2.4.3
Check water chemistry
before selecting the
treatment option to
determine whether the
water contains organic
material which will foul the
resin, or whether the water
contains insoluble iron or
manganese which foul the
resin.
Manganese.

Turbidity.
Provide pre-treatment (eg,
filters) to remove particulate
matter from the water.

Check when the exchanger
is first installed that it has
been properly packed.
Signs that action
is needed



Ensure that air cannot come
into contact with the water
before it enters the ionexchange unit to avoid
oxidation of iron and
manganese.

Channels in
the ionexchange
resin bed.


Corrective action
Manganese
concentration
more than
50% of its
MAV.
Turbid water
entering the
ion-exchange
unit.

Pretreat the
water to remove
organic matter.

Consider a
different
treatment
process.

Locate and seal
paths by which
air may enter
the system
before the ionexchange unit.

Install
appropriate pretreatment, or
improve the
performance of
the treatment
already in use.
Exchange unit
rapidly fouled.
Manganese.

Manganese
concentration
more than
50% of its
MAV.

Repack the
exchanger or
return to the
manufacturer.
Microbiological
quality.

High counts
of total
bacteria.

Regenerate and
back-flush.


Hardness not
being
reduced.
Clean resin to
remove bead
fouling.


Iron and/or
manganese
not being
removed.
Disinfect the
water after the
ion-exchanger.

Odour.
Event: BUILD-UP OF GERMS IN THE RESIN BED
Possible hazards: Germs.
Level of risk: Low1
P8.2.5.1

Organic
matter and
microorganisms
trapped in the
resin bed.


1
Regeneration of the resin at 
the frequency
recommended by the

manufacturer. This will also

back-flush the bed and
remove organic material.

Regularly clean (de-foul) the

resin beads with the
recommended cleaning
agent if iron or manganese
are present in the water.
Carry out treatment to
remove organic matter from
the water before the
softener.
Calcium.
Magnesium.
Iron.
Manganese.
The consequences of the event, and therefore the level of risk, will be influenced by how well subsequent
disinfection processes work.
Ref P8.2
Version 1, January 2014
Water Safety Plan Guide: Treatment
Processes – Iron and Manganese Removal
11
Contingency Plans
If an event happens despite preventive and corrective actions you have taken, you may need
to consult with the Medical Officer of Health to assess how serious a problem is.
Event – Faecal matter gets into the water through the aerator
Indicators:
Required
actions:
Responsibility:
12

Faecal indicator organisms or pathogens are continually detected
in the water leaving the plant.

Knowledge of an animal having entered the aerator.

Widespread sickness in the community linked to the water
supply.

Follow the actions given in Figure 3.2 of the DWSNZ:2000.

Identify the reason for the failure and rectify.

Record cause of system failure and steps taken to correct.

Modify your water safety plan if necessary.
Manager designated responsible for the water supply.
Water Safety Plan Guide: Treatment
Processes – Iron and Manganese Removal
Ref P8.2
Version 1, January 2014
Event – Very high oxidant concentration
Indicators:
Required
actions:
Responsibility:

Knowledge of a major spillage or overdose of oxidant into the
water.

Pink colour of the water (KMnO4 overdose).

Inability to obtain pink colour from DPD chlorine indicator
despite high chlorine dose rates (NB this indicates chlorine
levels well in excess of the MAV – very high chlorine or chlorine
dioxide levels bleach the pink colour that normally develops in
their presence).

Water develops a strongly chlorinous odour.

Widespread complaints of taste and odour, or black particles in
the water or staining (KMnO4 overdose), or illness in the
community.

Close down the plant. Provide another source of potable water
until water of acceptable quality can again be supplied.

Inform the MOH of the situation.

Identify the cause of the problem and rectify.

Dump the reservoir water, or add chemicals to neutralise the
oxidant if more appropriate (neutralisation may be required
before any water is dumped anyway).

Flush the distribution system, if excessive levels of chlorine are
also present in the distribution system, and monitor water quality
until chlorine concentrations are again back to normal operating
levels.

Warn consumers to thoroughly flush their taps before drawing
water for use (if they are likely to have been affected).

Record cause of system failure and steps taken to correct.

Modify your water safety plan if necessary.
Manager designated responsible for the water supply.
Ref P8.2
Version 1, January 2014
Water Safety Plan Guide: Treatment
Processes – Iron and Manganese Removal
13
Water Safety Plan Performance
Assessment
To make sure that your supply’s water safety plan (formerly known as a Public Health Risk
Management Plan, PHRMP) is working properly, periodic checks are needed. The overview
document outlines what needs to be done. The following table provides the detailed
information for checking this particular supply element.
What to measure or
observe:

Chlorine, chlorine dioxide or KMnO4 residuals.

Faecal indicators (E. coli).

Manganese concentrations greater than 50% of the MAV
in the treated water.
Follow the protocols set out in DWSNZ:2000.
Note that the presence of faecal indicators may be influenced by
factors other than the operation of the aerator.
How often:
What to do with the
results:
Responsibility:
14

For the monitoring frequencies for FAC and E. coli
measurements see DWSNZ:2000 Section 3.3.2.

Manganese should be monitored at least once a month if
not in transgression of the MAV.

Record results to meet legislative requirements or to allow
water safety plan performance assessment. The WINZ
database is good for this.

The collected data need to be periodically reviewed to see
whether problems with this supply element are
developing. This should be done as frequently as the
manager responsible considers necessary to minimise risk
to public health arising from this supply element.

Should this review show any unusual incidents, indicate
that proper procedures are not being carried out, highlight
poor laboratory results or indicate that poor water quality
is reaching customers, then review the procedures for
managing iron and manganese removal.

Evaluate the monitoring results, and any actions taken as
the result of having to implement a contingency plan, to
see if the water safety plan needs modification – eg,
preventive measures are up to date; the contingency plan
steps are still adequate; and changes to the iron and
manganese removal process are recognised in the plan.
Manager designated responsible for the water supply.
Water Safety Plan Guide: Treatment
Processes – Iron and Manganese Removal
Ref P8.2
Version 1, January 2014