NWPTRT052
Operate and control hypochlorite disinfection processes


Application

This unit describes the skills required to monitor and operate hypochlorite disinfection systems and report on process quality control. This includes the skills required to working safely with sodium hypochlorite solutions and calcium hypochlorite solids, including their safe handling, transport and storage and implementation of emergency response procedures.

This unit applies to those working as operational staff with specific responsibility for hypochlorite disinfection systems in water and wastewater treatment plants.

The skills and knowledge described in this unit must be applied within the legislative, regulatory and policy environment in which they are carried out. Organisational policies and procedures must be consulted and adhered to, particularly those related to WHS and handling of dangerous goods.

Those undertaking this unit would work under supervision, while performing routine tasks, in a range of familiar contexts.

No licensing, legislative or certification requirements apply to unit at the time of publication.


Elements and Performance Criteria

ELEMENTS

PERFORMANCE CRITERIA

Elements describe the essential outcomes

Performance criteria describe the performance needed to demonstrate achievement of the element. Where bold italicised text is used, further information is detailed in the range of conditions section.

1. Plan and prepare for work

1.1 Determine work requirements from job specification and plans.

1.2 Select and check equipment and hypochlorite supplies to meet safety requirements of task and site.

1.3 Select, fit and use personal protective equipment.

1.4 Handle and store hypochlorite chemicals to maximise shelf life and reduce loss of available chlorine.

1.5 Conduct the percentage available chlorine test.

2. Monitor process performance

2.1 Monitor hypochlorite disinfection processes according to agreed schedule and procedures.

2.2 Collect samples and conduct process tests.

2.3 Make process adjustments as required to maintain effectiveness of hypochlorite disinfection.

3. Apply chemical dosing

3.1 Prepare and apply hypochlorite chemicals.

3.2 Control hypochlorite dosing to maintain required residual.

4. Complete documentation

4.1 Maintain information relating to hypochlorite supply and usage.

4.2 Collect and record process data.

4.3 Report observations outside defined parameters for further action.

Evidence of Performance

Evidence required to demonstrate competence must satisfy all of the requirements of the elements and performance criteria. The candidate must be assessed in at least one type of process, in at least one type of technology and in at least one type of dosing procedure listed in the Range of Conditions. If not otherwise specified the candidate must demonstrate evidence of performance of the following on at least one occasion.

applying policies, standard operating procedures and regulatory standards

performing work-related calculations

identifying and responding to process faults and control system faults

identifying hazards

performing hypochlorite tests and chlorine residual sampling and testing

interpreting safety data sheets (SDS)

monitoring, operating and reporting on hypochlorite disinfection systems

selecting and using appropriate tools and equipment, including personal protective equipment

collecting and reporting process data

preparing and applying hypochlorite dosing safely

performing process calculations, including at least one of:

feed rate

dosage

Ct


Evidence of Knowledge

Evidence required to demonstrate competence must satisfy all of the requirements of the elements and performance criteria. If not otherwise specified the depth of knowledge demonstrated must be appropriate to the job context of the candidate.

properties and chemistry of hypochlorite chemicals

effects of pH, time, temperature, UV exposure and impurities on hypochlorite breakdown

microbiological guidelines

reactions with water to produce hypochlorous acid/hypochlorite ion

impact of pH

chlorine demands, including:

ammonia

natural organic matter (NOM)

turbidity

iron, manganese and nitrite

disinfection by-products (DBP)

breakpoint

contact time

hypochlorite dosing system layout for sodium hypochlorite and/or calcium hypochlorite dosing systems

hazardous substances handling

risk factors and potential hazards associated with hypo chlorination

work-related hypochlorite calculations

hypochlorite dosing processes

automatic feed rate control systems

SDS


Assessment Conditions

Competency should be assessed in an actual workplace or in a simulated environment, with access to equipment and infrastructure appropriate to the outcome. Competency should be demonstrated over time to ensure the candidate is assessed across a variety of situations.

Some components of this unit require assessment in a workplace environment therefore the unit is not suitable for fully external or electronic based assessment.

Assessors must satisfy the NVR/AQTF mandatory competency requirements for assessors.


Foundation Skills

The foundation skills demands of this unit have been mapped for alignment with the Australian Core Skills Framework (ACSF). The following tables outline the performance levels indicated for successful attainment of the unit.

Further information on ACSF and the foundation skills underpinning this unit can be found in the Foundation Skills Guide on the GSA website.


Range Statement

Processes include:

sodium hypochlorite solution

sodium hypochlorite

Technologies include:

calcium hypochlorite granules

calcium hypochlorite tablets

Dosing procedures include:

chlorinator shutdown, start up and isolation

purging operations

leak testing

dosing pump checks


Competency Field

Treatment