This unit is required by technical staff with responsibility for optimising sedimentation and clarification processes in water and wastewater treatment plants. This role may be a single operator or may be performed as part of a team with some responsibility for team coordination and supervision depending on the size of the treatment plant.

ELEMENT

PERFORMANCE CRITERIA

1Evaluate sedimentation and clarification process performance.

1.1 Review existing process performance data against relevant organisational or legislative requirements.

1.2 Identify the impact of changing incoming water quality on sedimentation and clarification processes in a range of conditions.

1.3 Identify and coordinate any additional sampling and testing required for valid evaluation of current process performance.

2Investigate sedimentation and clarification assets.

2.1 Review existing fault reports and other relevant plant asset information.

2.2 Investigate the operational status of plant components with reference to manufacturers' and plant designers' specifications.

3Investigate process optimisation.

3.1 Review relevant fault and incident reports and remedial actions taken.

3.2 Investigate potential changes to operational processes to identify possible optimisation strategies.

4Plan process optimisation.

4.1 Determine plant configuration and revised operational processes for process optimisation.

4.2 Plan a trial to test the performance of the determined optimisation options.

4.3 Compile a report making recommendations on optimisation options.

Required skills:

conduct investigations and report on operational or control system problems

coordinate sedimentation and clarification inspection, sampling and testing

perform various calculations to provide data for the analysis and development of options and solutions, such as surface loading rate, upflow velocity, detention time and weir loading rate

operate control and communication systems

use safety and personal protective equipment

communicate with colleagues, consultants and suppliers

produce optimisation reports

interpret a range of complex and technical documents, including relevant:

regulatory, legislative, licensing and organisational requirements

codes and standards

specifications

organisational policies

articulate complex ideas clearly

work collaboratively with relevant stakeholders and team members

analyse problems and recommend appropriate remedial solutions

identify risks and hazards

identify opportunities for improved water management

participate in the provision of appropriate information to inform workplace processes

manage work priorities

use information effectively to improve work performance.

prepare and apply chemical dosing.

Required knowledge:

principles that form the basis of sedimentation and clarification processes

types of sedmentation and clarification processes

re-establishing sludge blankets

polymers and weighting agents

principles of sedmentation and clarification system maintenance

system layout

pumping and valving systems

relevant historical records

range of appropriate measuring and testing procedures

investigation procedures

risk management principles related to sedimentation and clarification systems

relevant legislation, standards and workplace policies and procedures

chemical dosing processes.

The evidence guide provides advice on assessment and must be read in conjunction with the performance criteria, required skills and knowledge, range statement and the Assessment Guidelines for the Training Package.

Critical aspects for assessment and evidence required to demonstrate competency in this unit

The candidate should demonstrate the ability to evaluate system performance and investigate and report on optimisation of sedimentation and clarification processes including:

reviewing existing sedimentation and clarification process performance with reference to historical data, differences in incoming water quality and plant configuration

identifying data deficiencies and organising additional data collection through appropriate sampling and testing

assessing fault reports and investigating the current operational status of sedimentation and clarification plant components

investigating current and potential chemical addition practices

planning trials to test the performance of the determined sedimentation and clarification optimisation options and compiling reports making recommendations.

Context of and specific resources for assessment

Access to the workplace and resources, including:

documentation that should normally be available in a water industry organisation

relevant codes, standards and government regulations.

Where applicable, physical resources should include equipment modified for people with disabilities.

Access must be provided to appropriate learning and assessment support when required.

Assessment processes and techniques must be culturally appropriate, and appropriate to the language and literacy capacity of the candidate and the work being performed.

Validity and sufficiency of evidence requires that:

competency will need to be demonstrated over a period of time reflecting the scope of the role and the practical requirements of the workplace

where the assessment is part of a structured learning experience the evidence collected must relate to a number of performances assessed at different points in time and separated by further learning and practice

a decision of competence only taken at the point when the assessor has complete confidence in the person's competence over time and in various contexts

all assessment that is part of a structured learning experience must include a combination of direct, indirect and supplementary evidence

where assessment is for the purpose of recognition (RCC/RPL), the evidence provided will need to be authenticated and show that it represents competency demonstrated over a period of time

assessment can be through simulated project-based activity and must include evidence relating to each of the elements in this unit.

In all cases where practical assessment is used it will be combined with targeted questioning to assess the underpinning knowledge. Questioning will be undertaken in a manner appropriate to the skill levels of the operator and cultural issues that may affect responses to the questions, and will reflect the requirements of the competency and the work being performed.

The range statement relates to the unit of competency as a whole. It allows for different work environments and situations that may affect performance. Bold italicised wording, if used in the performance criteria, is detailed below. Essential operating conditions that may be present with training and assessment (depending on the work situation, needs of the candidate, accessibility of the item, and local industry and regional contexts) may also be included.

Organisational or legislative requirements may include:

organisational performance quality standards

standard operating procedures

quality assurance guidelines

federal, state and local environmental and water quality legislation

occupational health and safety requirements

water quality standards and guidelines.

Incoming water quality may include:

turbidity

colour

presence of algae

temperature.

Processes may include:

sludge blanket clarifiers

conventional clarifiers

tube settlers

high rate plate settlers

recirculating contact clarifiers

pulsator clarifiers

ballasted sedimentation.

Testing may include:

turbidity

true colour

float solids content.

Plant components may include:

valves

sludge pumps

impellers

sludge collection cones

sludge rake

tube and plate settlers

weirs or launders

dosing points.

Manufacturers' and plant designers' specifications may include:

surface loading rate

upflow velocity

detention time

weir loading rate

slurry recirculation rate

intended plant configuration.

Potential changes to operational processes may include:

flow rate

polymer addition

slurry recirculation rate

sludge wasting rate

sludge blanket concentration and depth.

Treatment

This unit contains employability skills.