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Demonstrate knowledge of water treatment filtration processes
Level
4
Credits
10
Purpose
People credited with this unit standard are able to demonstrate knowledge of:
the purpose and principles of filtration; rapid sand filters; membrane filtration;
and other filtration methods, in water treatment.
Subfield
Water Industry
Domain
Water Treatment
Status
Registered
Status date
19 September 2008
Date version published
19 September 2008
Planned review date
31 December 2013
Entry information
Open.
Accreditation
Evaluation of documentation and visit by NZQA, industry
and teaching professional in the same field from another
provider.
Standard setting body (SSB)
Primary Industry Training Organisation
Accreditation and Moderation Action Plan (AMAP) reference
0179
This AMAP can be accessed at http://www.nzqa.govt.nz/framework/search/index.do.
Special notes
None.
Elements and performance criteria
Element 1
Demonstrate knowledge of the purpose and principles of filtration in water treatment.
Performance criteria
1.1
The purpose of filtration in water treatment is described in terms of particulate
removal.
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1.2
Filtration methods are described in terms of the impact of filter loading.
Range
1.3
rapid sand, membrane cartridge.
The removal mechanisms in filtration are described in terms of their processes.
Range
includes but is not limited to – straining, adsorption, filter ripening,
aperture size.
Element 2
Demonstrate knowledge of rapid sand filters in water treatment.
Performance criteria
2.1
Rapid sand filters are outlined in terms of the design options used in New
Zealand water treatment plants.
Range
2.2
Rapid sand filter operating mode options are described in terms of flow and
head loss versus filter run time.
Range
2.3
filtration loading rate calculation, rising head, declining rate, flow
balancing, filter ripening.
Rapid sand filter operating backwashing is described in terms of start points and
sequence options.
Range
2.4
flow paths, filter floors, sand size, alternate media, uniformity
coefficient, multi-media, media depth, head loss build-up, floc
shear, backwash, pressure filler, automatic valveless gravity.
start points – time, flow, turbidity, head loss;
sequence options – air scour, water wash, combined air water
wash.
Operating problems of rapid sand filters are described in terms of their probable
causes and remedies.
Range
problems – mudballing, filter cracking, air blinding, floc carryover,
turbidity, breakthrough spikes;
causes – poor backwashing, high poly doses;
remedies – improved backwashing, caustic/acid soaking.
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Element 3
Demonstrate knowledge of membrane filtration in water treatment.
Performance criteria
3.1
Membrane filtration is described in terms of membrane material options in New
Zealand water treatment plants.
Range
3.2
Filtration size terms are defined in terms of pore size and specification.
Range
3.3
pore size – microfiltration, ultrafiltration, nanofiltration;
specification – nominal, absolute.
Membrane filtration plants are described in terms of design options and plant
layout in New Zealand water treatment plants.
Range
3.4
cartridge membranes, synthetic membranes, bag filters.
includes but is not limited to – filament bundles, flow path,
crossflow, direct, submerged, vacuum pressure, capacity.
Membrane filter plant operations are described in terms of backwash initiation,
cleaning factors, and integrity testing.
Range
head loss increases, run times, air scour, filament failure checks,
pressure decay test.
Element 4
Demonstrate knowledge of other filtration methods in water treatment.
Performance criteria
4.1
Slow sand filtration is described in terms of its concept, components and
effectiveness.
Range
4.2
Diatomaceous earth filtration is described in terms of its concept, components
and effectiveness.
Range
4.3
typical design, schmutzdecke layer, ripening, cleaning, final water
quality.
septums, pre-coat, cleaning, final water quality, pressure and
vacuum systems.
Granular activated carbon (GAC) filtration is described in terms of its concept,
components and effectiveness.
Range
typical design, GAC media, adsorption, final water quality.
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4.4
Ion exchange filtration is described in terms of its concept, components and
effectiveness.
Range
typical design, media, cartridge options, reactivation, zeolites,
iron/manganese/hardness removal, final water quality.
Please note
Providers must be accredited by NZQA, or an inter-institutional body with delegated
authority for quality assurance, before they can report credits from assessment against
unit standards or deliver courses of study leading to that assessment.
Industry Training Organisations must be accredited by NZQA before they can register
credits from assessment against unit standards.
Accredited providers and Industry Training Organisations assessing against unit standards
must engage with the moderation system that applies to those standards.
Accreditation requirements and an outline of the moderation system that applies to this
standard are outlined in the Accreditation and Moderation Action Plan (AMAP). The
AMAP also includes useful information about special requirements for organisations
wishing to develop education and training programmes, such as minimum qualifications for
tutors and assessors, and special resource requirements.
Comments on this unit standard
Please contact the Primary Industry Training Organisation standards@primaryito.ac.nz if
you wish to suggest changes to the content of this unit standard.
 New Zealand Qualifications Authority 2016