Elements and Performance Criteria

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.
Wastewater microorganisms may include:
fungi
bacteria:
aerobic
anaerobic
facultative
autotrophs
heterotrophs
filament and foam causing
protozoa
amoebae
ciliates
flagellates
metazoa
algae
cyanobacteria
helminths
General characteristics of microorganisms may include:
evolutionary development
source
structure
life cycle
growth rates and requirements
Wastewater characteristics may include:
presence of inhibitory substances, such as heavy metals, synthetic organics
nutrients - macro and micro
temperature
dissolved oxygen
organic loading
pH
Problems caused by microorganisms may include:
bulking
foaming
inefficient nitrogen or phosphorus removal
lack of nitrification
high effluent suspended solids or biological oxygen demand (BOD)
volatile solids reduction
volatile acids to alkalinity ratio
gas production rate - methane, carbon dioxide
Organisational and legislative requirements may include:
organisational performance standards
standard operating procedures
quality assurance
federal, state and local environmental and water quality legislation
Manufacturers' or plant designers' specifications may include:
Food:Microorganism (F:M) ratio
Mean Cell Residues Time (MCRT)
Mixed Liquor Suspended Solids (MLSS)
phase timing in intermittent or batch processes
temperature
recirculation rates.
Process control strategies may include:
Food:Microorganism (F:M) ratio
Mean Cell Residues Time (MCRT)
Mixed Liquor Suspended Solids (MLSS)
return and waste activated sludge rates
chemical and nutrient addition
pre-treatment to remove inhibitory or toxic substances
alkalinity and pH correction
mixed liquor recycle rates
phase timing in intermittent or batch processes
recirculation rates
addition of nutrients
temperature
pre-treatment to remove inhibitory or toxic substances
alkalinity and pH correction
chemical addition, such as:
chlorine
nutrients
aluminium and iron salts
flow or feed rate
mixing rate
sludge wastage rate

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 identify wastewater microorganisms and select appropriate measures to optimise the growth of beneficial microorganisms including:
identifying a range of wastewater microorganisms, and their general characteristics and types of problems caused
identifying effluent quality and select process control strategies to optimise the growth of beneficial microorganisms
prepare reports outlining the optimum treatment for various microorganisms including measures to ensure validity
Context of and specific resources for assessment
Access to the workplace and resources, including:
documentation that should normally be available in a water treatment 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
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.