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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
255977  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  8 
REGISTRATION STATUS REGISTRATION START DATE REGISTRATION END DATE SAQA DECISION NUMBER
Passed the End Date -
Status was "Reregistered" 		 2018-07-01  2023-06-30  SAQA 06120/18 
LAST DATE FOR ENROLMENT LAST DATE FOR ACHIEVEMENT
2026-06-30   2029-06-30  

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 replaces: 
US ID Unit Standard Title Pre-2009 NQF Level NQF Level Credits Replacement Status
115946  Demonstrate knowledge of the principles and application of potable water science  Level 4  NQF Level 04  20   

PURPOSE OF THE UNIT STANDARD 
The person achieving this unit standard will be able to explain water related chemistry and its application in the water treatment process. This competence will provide the learner with a knowledge and understanding of the composition of untreated water, it's chemical and physical characteristics, water biology and the application of chemical processes in water treatment. This will provide the learner with a scientific understanding of the industry in which she/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 
  • Mathematical literacy at NQF Level 3.
  • Communication skills at 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. 

    ASSESSMENT CRITERIA     

    ASSESSMENT CRITERION 1 
    The interrelationship of pH, alkalinity and acidity is explained in terms of its relevance to the water treatment process. 

    ASSESSMENT CRITERION 2 
    The origin and implications of dissolved substances in raw water is explained in terms of the effects on users. 

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

    ASSESSMENT CRITERION 4 
    The relationship between conductivity and Total Dissolved Solids (TDS) (salts) is explained in order to measure salinity. 

    ASSESSMENT CRITERION 5 
    Process tests are demonstrated using the relevant equipment in accordance with works procedures. 

    ASSESSMENT CRITERION 6 
    Results are interpreted in order to determine their implications for the water treatment process. 

    SPECIFIC OUTCOME 2 
    Explain the physical characteristics of raw water. 

    ASSESSMENT CRITERIA     

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

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

    ASSESSMENT CRITERION 3 
    The origin of turbidity, taste, odour and colour are explained in terms its effect on the treateability of water. 

    ASSESSMENT CRITERION 4 
    Common causes of poor tastes and odours are identified and explained in terms of the guidelines of drinking water standards. 

    SPECIFIC OUTCOME 3 
    Explain water microbiology and perform microbiological tests. 

    ASSESSMENT CRITERIA     

    ASSESSMENT CRITERION 1 
    Common waterborne and water related diseases including symptoms and origins and their causes are described in terms of their implications to water quality. 

    ASSESSMENT CRITERION 2 
    Common infestations of filter media are identified and explained in terms of their relevance to the water treatment process. 

    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 in order to ensure compliance with standards. 

    SPECIFIC OUTCOME 4 
    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 in order to ensure compliance. 

    ASSESSMENT CRITERION 2 
    Methods of treating water containing colour compounds are explained in terms of their effectiveness and efficiency. 

    ASSESSMENT CRITERION 3 
    The principles of pH correction and stabilisation are explained to produce stable 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.
  • Moderation should also encompass achievement of the competence described both in individual unit standards as well as the integrated competence described in the qualification. 
    		•

    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 to ensure the removal of nuisance causing substances by applying the correct chemical and biological methods. 

    UNIT STANDARD CCFO WORKING 
    Work effectively with others as a member of a team, group, organisation, and community to provide water that is suitable for use in all respects. 

    UNIT STANDARD CCFO ORGANISING 
    Plan, organise and manage oneself and one`s activities responsibly and effectively in order to optimize the treatment process. 

    UNIT STANDARD CCFO COLLECTING 
    Collect, analyse, organise and critically evaluate information on the quality of the treated water in order to ensure compliance with standards for drinking water. 

    UNIT STANDARD CCFO COMMUNICATING 
    Communicate effectively using visual, mathematical and/or language skills in the form of oral and/or written presentation to provide information to management and the community on water quality. 

    UNIT STANDARD CCFO SCIENCE 
    Use science and technology effectively and critically, showing responsibility towards the environment and health of others by applying the principles of water science to produce safe water for drinking and reducing the impact of residues on the environment. 

    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 as illustrated by the fact that adding flocculants to water lowers the pH which must be corrected by adding lime. 

    UNIT STANDARD ASSESSOR CRITERIA 
    N/A 

    REREGISTRATION HISTORY 
    As per the SAQA Board decision/s at that time, this unit standard was Reregistered in 2012; 2015. 

    UNIT STANDARD NOTES 
    This unit standard replaces unit standard 115946, "Demonstrate knowledge of the principles and application of potable water science", Level 4, 20 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
    Elective  61709   Further Education and Training Certificate: Water and Wastewater Treatment Process Control Supervision  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. CHILUTSI TRADING ENTERPRISE 
    2. EMANZINI STAFFING SOLUTIONS (PTY) LTD 
    3. ERGO MAPHELONG INSTITUTE (PTY) LTD 
    4. ERWAT 
    5. KGWEBISWANO SUPPLIES & SERVICES 
    6. PROGRESSIVE SCHOOL OF BUSINESS AND ENGINEERING (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.