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SOUTH AFRICAN QUALIFICATIONS AUTHORITY 
REGISTERED UNIT STANDARD THAT HAS PASSED THE END DATE: 

Demonstrate knowledge of the principles and application of potable water science 
SAQA US ID UNIT STANDARD TITLE
115946  Demonstrate knowledge of the principles and application of potable water science 
ORIGINATOR
SGB Water Sector 
PRIMARY OR DELEGATED QUALITY ASSURANCE FUNCTIONARY
-  
FIELD SUBFIELD
Field 12 - Physical Planning and Construction Civil Engineering Construction 
ABET BAND UNIT STANDARD TYPE PRE-2009 NQF LEVEL NQF LEVEL CREDITS
Undefined  Regular  Level 4  NQF Level 04  20 
REGISTRATION STATUS REGISTRATION START DATE REGISTRATION END DATE SAQA DECISION NUMBER
Passed the End Date -
Status was "Reregistered" 		 2007-05-15  2008-06-11  SAQA 0160/05 
LAST DATE FOR ENROLMENT LAST DATE FOR ACHIEVEMENT
2009-06-11   2012-06-11  

In all of the tables in this document, both the pre-2009 NQF Level and the NQF Level is shown. In the text (purpose statements, qualification rules, etc), any references to NQF Levels are to the pre-2009 levels unless specifically stated otherwise.  

This unit standard is replaced by: 
US ID Unit Standard Title Pre-2009 NQF Level NQF Level Credits Replacement Status
255977  Demonstrate knowledge of the principles and application of potable water science  Level 4  NQF Level 04  8   

PURPOSE OF THE UNIT STANDARD 
The qualifying learner achieving this unit standard in combination with context expertise, will be able to explain water related chemistry and its application in the water purification process. This competence will provide the learner with a knowledge and understanding of the composition of raw water, it's chemical and physical characteristics, water biology and the application of chemical processes in water purification. This will provide the learner with a scientific understanding of the industry in which s/he operates and will provide a basis for learning in other related sectors. In acquiring this competence the qualifying learner will lay a good foundation for future learning and better understand the broader context of own work. 

LEARNING ASSUMED TO BE IN PLACE AND RECOGNITION OF PRIOR LEARNING 
  • Arithmetic calculations NQF level 3
  • Literacy NQF level 3
  • Knowledge of coagulation, flocculation, clarification and separation, filtration, stabilisation, disinfection, sampling, jar tests and safety practices 
    		•

    UNIT STANDARD RANGE 
    Dissolved substances
  • Carbonate, bicarbonate, sulphate, nitrates, chloride, sodium, fluoride, calcium, magnesium, iron, manganese, total dissolved solids (TDS) and Phosphate

    Colloidal/suspended particles or material
  • Silt, clay, micro organisms, oil, algae and plant material, naturally occurring colour forming compounds e.g. humic acids

    Relevant laboratory analysis
  • pH, turbidity, total dissolved solids (TDS), conductivity, alkalinity, hardness, temperature, suspended solids analysis

    Physical properties
  • Temperature, taste, odour, colour, conductivity and turbidity, density, specific gravity (SG), viscosity, suspended solids, colloidal matter

    Origin of taste, odour and colour
  • Algae, plant life, animal life, bacteria, industrial effluent, organic and inorganic substances

    Water borne and water related diseases
  • Cholera, dysentery, cryptosporidiosis and giardiasis, gastric enteritis, bilharzia, malaria and trachoma

    Infestations of filter media
  • Insect larvae, algae and worms (e.g. blood worms)

    Microbiological tests
  • Plate counts, total coliforms and faecal coliforms

    Stabilisation process
  • pHs, Langelier index, precipitation potential 
    		•

    Specific Outcomes and Assessment Criteria: 

    SPECIFIC OUTCOME 1 
    Describe the chemical characteristics of raw water and perform relevant laboratory tests. 

    ASSESSMENT CRITERIA     

    ASSESSMENT CRITERION 1 
    The concepts of pH, alkalinity and acidity are explained and its relevance to the treatment process is described and explained. 

    ASSESSMENT CRITERION 2 
    The origin and implications of dissolved substances in raw water is explained. 

    ASSESSMENT CRITERION 3 
    The concept of hardness is explained and its relevance to the treatment process is described. 

    ASSESSMENT CRITERION 4 
    The relationship between conductivity and Total Dissolved Solids (TDS) (salts) is explained. 

    ASSESSMENT CRITERION 5 
    Relevant laboratory analysis and calculations are completed in accordance with work procedures. 

    ASSESSMENT CRITERION 6 
    Results are interpreted and the implications for the water purification process are explained. 

    SPECIFIC OUTCOME 2 
    Describe the physical characteristics of raw water and perform relevant laboratory tests. 

    ASSESSMENT CRITERIA     

    ASSESSMENT CRITERION 1 
    Physical properties that affect the quality of water are identified and their relevance to the treatment process is described. 

    ASSESSMENT CRITERION 2 
    The origin and implications of colloidal/suspended particles or material in raw water is explained. 

    ASSESSMENT CRITERION 3 
    The origin of turbidity, taste, odour and colour are explained. 

    ASSESSMENT CRITERION 4 
    Relevant laboratory analysis and calculations are completed in accordance with work procedures. 

    ASSESSMENT CRITERION 5 
    Results are interpreted and the implications for the water purification process are explained. 

    SPECIFIC OUTCOME 3 
    Explain water microbiology and perform microbiological tests. 

    ASSESSMENT CRITERIA     

    ASSESSMENT CRITERION 1 
    Common water born and water related diseases including symptoms and origins and their causes are described. 

    ASSESSMENT CRITERION 2 
    Common infestations of filter media are identified and their relevance to the water treatment process is described. 

    ASSESSMENT CRITERION 3 
    Relevant microbiological tests and calculations are completed in accordance with work procedures. 

    ASSESSMENT CRITERION 4 
    Results are interpreted and the effects on water treatment are explained. 

    SPECIFIC OUTCOME 4 
    Describe and apply water science principles to the chemical process involved in water treatment. 

    ASSESSMENT CRITERIA     

    ASSESSMENT CRITERION 1 
    Methods and chemicals used to control turbidity are described and dosing rate is calculated based on jar tests. 

    ASSESSMENT CRITERION 2 
    Methods of treating water containing organic colour compounds are explained. 

    ASSESSMENT CRITERION 3 
    The principles of chemical disinfections and the operation and control of the disinfection process on plants are described and dosing rates are accurately calculated. 

    ASSESSMENT CRITERION 4 
    Chemicals used for pH correction and stabilisation are identified and dosing rate is calculated accurately. 

    ASSESSMENT CRITERION 5 
    pH correction and stabilisation processes are explained and applied to the process to correct pH and to stabilise the water. 


    UNIT STANDARD ACCREDITATION AND MODERATION OPTIONS 
  • Anyone assessing a learner or moderating the assessment of a learner against this unit standard must be registered as an assessor with the relevant ETQA.
  • Any institution offering learning that will enable the achievement of this unit standard must be accredited as a provider with the relevant ETQA.
  • Assessment and moderation of assessment will be overseen by the relevant ETQA according to the ETQA's policies and guidelines for assessment and moderation.
  • Moderation must include both internal and external moderation of assessments at exit points of the Qualification, unless ETQA policies specify otherwise. 
    		•

    UNIT STANDARD ESSENTIAL EMBEDDED KNOWLEDGE 
  • Basic chemical principles: e.g. atoms, molecules, ions, electrical charges, chemical bonds, valences, solutions and suspensions, acids, bases, gases, liquids, solids.
  • The classification system for states of matter (liquid, solid, gas).
  • The structure and nomenclature of atoms, ions and molecules common to water treatment (e.g. calcium carbonate Ca CO3).
  • Water microbiology including bacteria, viruses and protozoa, algae, invertebrates, algal count, the following tests (i.e. heterotrophic plate count, total coliforms, and E.coli, faecal coliforms)
  • Common and scientific names of water treatment chemicals.
  • Stabilisation of water and methods used for measuring water stability.
  • The formulation of chemical reaction equations from empirical information.
  • Stoichiometric calculations pertaining to chemical changes, especially those involved with the treatment of potable water.
  • The description and computation of solutions according to different systems of units (mol/l, g/l, mg/l, µg/l, %(m/v), %(m/m), equivalence per litre)
  • The principles of chemical equilibrium.
  • The hydroxide, carbonate, bicarbonate and carbonic acid equilibrium system in natural waters.
  • The presence of the hydrogen ion and hydroxyl ion equilibrium in aqueous solution, with special reference to the pH of the solutions.
  • The measurement and relevance of mass, weight, volume, density, specific gravity (SG), surface tension, viscosity and temperature.
  • The characteristic differences between solutions and suspensions (which include colloids and emulsions).
  • The Societé Internationale (SI) system of measurement units in the expression of physical quantities/ properties.
  • Complementary values between the different practical systems of units applicable to potable water treatment plants (United States, United Kingdom, Societé Internationale (SI).
  • Trihalomethanes (THM) created during the chlorination of water containing organic material (including test problems).
  • Alternative disinfection methods e.g. ozone, ultraviolet (UV), chlorine dioxide, sodium hypochlorite and chloramination.
  • Chlorine breakpoint and factors affecting the effectiveness of chlorination.
  • Preparation of proprietary media for microbiological tests.
  • Sampling techniques for microbiological testing of purified water.
  • Alternative methods to control chemical dosing to remove turbidity e.g. Zeta meters
  • Treatment of low turbidity water by adding colloidal compounds such as bentonite clay.
  • Temperature (Chemical reaction rate, clarifier performance, stratification in water impoundments). 
    		•

    UNIT STANDARD DEVELOPMENTAL OUTCOME 
    N/A 

    UNIT STANDARD LINKAGES 
    N/A 


    Critical Cross-field Outcomes (CCFO): 

    UNIT STANDARD CCFO IDENTIFYING 
    Identify and solve problems in which responses display that responsible decisions using critical and creative thinking have been made.

    Assessment criteria:
  • None 
    		•

    UNIT STANDARD CCFO WORKING 
    Work effectively with others as a member of a team, group, organisation, and community.

    Assessment criteria:
  • All 
    		•

    UNIT STANDARD CCFO ORGANISING 
    Plan, organise and manage oneself and one's activities responsibly and effectively.

    Assessment criteria:
  • All 
    		•

    UNIT STANDARD CCFO COLLECTING 
    Collect, analyse, organise and critically evaluate information.

    Assessment criteria:
  • Results are interpreted and the implications for the water purification process are explained.
  • Results are interpreted and the implications for the water purification process are explained.
  • Results are interpreted and the effects on water treatment are explained. 
    		•

    UNIT STANDARD CCFO COMMUNICATING 
    Communicate effectively using visual, mathematical and/or language skills in the form of oral and/or written presentation.

    Assessment criteria:
  • All 
    		•

    UNIT STANDARD CCFO SCIENCE 
    Use science and technology effectively and critically, showing responsibility towards the environment and health of others.

    Assessment criteria:
  • All 
    		•

    UNIT STANDARD CCFO DEMONSTRATING 
    Demonstrate an understanding of the world as a set of related systems by recognising that problem-solving contexts do not exist in isolation.

    Assessment criteria:
  • Results are interpreted and the implications for the water purification process are explained.
  • Results are interpreted and the implications for the water purification process are explained.
  • Results are interpreted and the effects on water treatment are explained.
  • The principles of chemical disinfections and the operation and control of the disinfection process on plants are described and dosing rates are accurately calculated.
  • Chemicals used for pH correction and stabilisation are identified and dosing rate is calculated accurately.
  • pH correction and stabilisation processes are explained and applied to the process to correct pH and to stabilise the water. 
    		•

    UNIT STANDARD ASSESSOR CRITERIA 
    N/A 

    UNIT STANDARD NOTES 
    This unit standard has been replaced by unit standard 255977, which is "Demonstrate knowledge of the principles and application of potable water science", Level 4, 8 credits.

    Integrated Assessment

    When conducting assessments, assessors must ensure that they are familiar with the full text of the unit standards being assessed. Assessors must ensure that the assessment covers the specific outcomes, critical cross-field outcomes and essential embedded knowledge by developing assessment activities and tools, which are appropriate to the contexts in which the learners are working. These activities and tools may include self-assessment, peer assessment, formative and summative assessment. It may be more effective and efficient to assess a number of unit standards together in an integrated way, thus reducing the overall number of assessments and ensuring that commonalities that exist among a number of unit standards are captured in a way that makes sense for assessment.

    Assessment Option

    Learners could be assessed using the following methods:
  • Oral or written questions
  • Evaluation of records and calculations
  • Observation 
    		•

    QUALIFICATIONS UTILISING THIS UNIT STANDARD: 
      ID QUALIFICATION TITLE PRE-2009 NQF LEVEL NQF LEVEL STATUS END DATE PRIMARY OR DELEGATED QA FUNCTIONARY
    Core  48910   Further Education and Training Certificate: Water Purification Processes  Level 4  NQF Level 04  Passed the End Date -
    Status was "Reregistered"     		 2023-06-30  EWSETA 


    PROVIDERS CURRENTLY ACCREDITED TO OFFER THIS UNIT STANDARD: 
    This information shows the current accreditations (i.e. those not past their accreditation end dates), and is the most complete record available to SAQA as of today. Some Primary or Delegated Quality Assurance Functionaries have a lag in their recording systems for provider accreditation, in turn leading to a lag in notifying SAQA of all the providers that they have accredited to offer qualifications and unit standards, as well as any extensions to accreditation end dates. The relevant Primary or Delegated Quality Assurance Functionary should be notified if a record appears to be missing from here.
     
    1. ERGO MAPHELONG INSTITUTE (PTY) LTD 


    All qualifications and part qualifications registered on the National Qualifications Framework are public property. Thus the only payment that can be made for them is for service and reproduction. It is illegal to sell this material for profit. If the material is reproduced or quoted, the South African Qualifications Authority (SAQA) should be acknowledged as the source.