24930 version 1
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Level 4
Credits 10
Purpose People credited with this unit standard are able to describe: the purpose of; the objectives and plant configuration options for; and tests and performance measures of, activated sludge wastewater treatment.
Subfield Water Industry
Domain
Status
Status date
Date version published
Wastewater Treatment
Registered
19 September 2008
19 September 2008
Planned review date
Entry information
31 December 2013
Open.
Replacement information
Accreditation
This unit standard replaced unit standard 17884.
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
1 Definition
Wastewater includes stormwater and sewage systems.
In the context of this unit standard, activated sludge treatment includes the separation process.
2 Assessment
The two plant configuration options selected for assessment for performance criteria
2.2 should also be the same as those assessed in 2.3 and 3.1.
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New Zealand Qualifications Authority 2020

24930 version 1
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Element 1
Describe the purpose of activated sludge wastewater treatment.
Performance criteria
1.1 The purpose of activated sludge treatment is described in terms of the stabilisation and reduction of contaminants.
1.2 Activated sludge treatment is described in terms of the process outputs.
Range Biochemical Oxygen Demand (BOD), suspended solids, nutrients, indicator organisms.
Element 2
Describe the objectives and plant configuration options for activated sludge wastewater treatment.
Performance criteria
2.1 Activated sludge treatment is described in terms of the process objectives and options.
Range loadings, aeration, settleability.
2.2 The plant configuration options for activated sludge treatment are described in terms of hydraulic layout options, and solids wasting and return methods.
Range evidence is required for at least two plant configuration options.
2.3 Plant configuration options for activated sludge treatment are described in terms of the advantages and disadvantages for each option.
Range evidence is required for at least one advantage and one disadvantage for each option assessed in 2.2.
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New Zealand Qualifications Authority 2020

24930 version 1
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Element 3
Describe tests and performance measures of activated sludge wastewater treatment.
Range evidence is required for one of the two plant configuration options assessed in
2.2.
Performance criteria
3.1 The process tests are described for each plant configuration option.
Range includes but is not limited to – Mixed Liquor Suspended Solids
(MLSS), sludge volume index, sludge age, Dissolved Oxygen
(DO) control.
3.2 The performance measures for activated sludge treatment are described in terms of efficiency and downstream effects.
Range BOD, suspended solids, nutrients, indicator organisms.
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.
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New Zealand Qualifications Authority 2020