Assess a wastewater treatment plant for optimal output, and describe critical points

Transcription

1 Page 1 of 5 Assess a wastewater treatment plant for optimal output, and describe critical points Level 5 Credits 12 Purpose People credited with this unit standard are able to: assess the wastewater source for a wastewater treatment plant; assess plant tuning in a wastewater treatment plant; describe how the unit processes in the plant interact and how to optimise plant output; describe the overall operation of a wastewater treatment plant; describe emergency situations and process failure conditions in a wastewater treatment plant; and demonstrate knowledge of critical points of wastewater treatment plant operation that may affect continuous operation, and identify adverse effects, preventive actions, and corrective actions. Subfield Domain Status Water Industry Wastewater Treatment Registered Status date 19 September 2008 Date version published 19 September 2008 Planned review date 31 December 2013 Entry information Accreditation Standard setting body (SSB) Open. Evaluation of documentation and visit by NZQA, industry and teaching professional in the same field from another provider. Primary Industry Training Organisation Accreditation and Moderation Action Plan (AMAP) reference 0179 This AMAP can be accessed at Special notes 1 Definitions Organisational procedures instructions to staff, and procedures which are documented in memo or manual format and are available in the workplace. These requirements include but are not limited to site specific requirements, manufacturers specifications, product quality specifications, and legislative or regulatory requirements.

2 Page 2 of 5 Critical points points in a process or in equipment where failure to function correctly can lead to adverse affects which may effect the treatment process or other processes in the treatment plant. Wastewater includes stormwater and sewage systems. On site on the site of a full scale, operating wastewater treatment plant. 2 Assessment The treatment plant used to demonstrate competence for this unit standard must include at least sludge digestion and biological processes, and have a variable wastewater inflow. This unit standard is to be assessed against on site. It is accepted that the range of inflow wastewater conditions set out in elements one and two are unlikely to occur at the time of the assessment which will thus need to be by way of explanation rather than actual demonstration. Elements and performance criteria Element 1 Assess the wastewater source for a wastewater treatment plant. 1.1 The range in wastewater quality is described in terms of the effects of weather, reticulation system integrity, seasonal variations, discharges, and organisational procedures. industrial, domestic. 1.2 Assessment of the treatment options appropriate to the characteristics of a given influent identifies the impacts of quality and flow, and is in accordance with variations in amount and type of organic loading, temperature, pollutants, chemical composition. 1.3 The rate of change of key variables is described relative to the ability of the plant control system to adjust plant reactions, and is in accordance with Element 2 Assess plant tuning in a wastewater treatment plant. 2.1 The plant flow rate is assessed in terms of wastewater quality variations and influent quality changes, dosing limitations, required output, storage.

3 Page 3 of The plant physical and biological processes are assessed in terms of raw wastewater quality variations and loading organic, inorganic, chemical. 2.3 Adjustments of the plant mechanical processes are assessed in response to raw wastewater quality and flow variations and mixing energies, sludge draw-off, flow balancing, flow diversion, mixing intensity. Element 3 Describe how the unit processes in the plant interact and how to optimise plant output. 3.1 The relationship between pairs of unit operations and their interaction is described in terms of the total plant performance. two of sedimentation, flotation, activated sludge, fixed growth reactor, oxidation pond, lagoon, disinfection, screening or grit removal, receiving environment. Element 4 Describe the overall operation of a wastewater treatment plant. 4.1 The water flow paths through a wastewater treatment plant and storage are physically identified in accordance with 4.2 The flow control elements are identified in terms of their functions and float switches, level measurements, pump runs, pressure switches, valves, flow meters. 4.3 The individual plant process sections are identified and described in terms of their functions and process objective, inflows, outflows, physical identification, wastewater quality changes. 4.4 Description of treated wastewater quality monitoring and plant automatic controls adjustment is in accordance with set points, ranges, instrument calibration, alarm points.

4 Page 4 of Manual control or intervention controls that are carried out are described in accordance with two of alarm response, manual pump control, valve operation, sludge transfer, aeration. Element 5 Describe emergency situations and process failure conditions in a wastewater treatment plant. 5.1 Critical and emergency situations are identified and explained in terms of the impacts on processes and appropriate responses in accordance with includes but is not limited to floods, mechanical failure, pipeline failure, power supply losses, chemical handling and spills, earthquake awareness. 5.2 Responses to process failures are identified and described in accordance with contingency plans in Element 6 Demonstrate knowledge of critical points of wastewater treatment plant operation that may affect continuous operation, and identify adverse effects, preventive actions, and corrective actions. 6.1 The critical points in treatment plant operation that may affect continuous operation are identified. 6.2 The adverse effects, the causes of the events leading to their occurrence and the level of risk are identified at each critical point. 6.3 The preventive and corrective actions for persistent problems or events related to each adverse effect are identified. Please note Providers must be accredited by NZQA, or an inter-institutional body with delegated authority for quality assurance, before they can report credits from assessment against unit standards or deliver courses of study leading to that assessment. Industry Training Organisations must be accredited by NZQA before they can register credits from assessment against unit standards.

5 Page 5 of 5 Accredited providers and Industry Training Organisations assessing against unit standards must engage with the moderation system that applies to those standards. Accreditation requirements and an outline of the moderation system that applies to this standard are outlined in the Accreditation and Moderation Action Plan (AMAP). The AMAP also includes useful information about special requirements for organisations wishing to develop education and training programmes, such as minimum qualifications for tutors and assessors, and special resource requirements. Comments on this unit standard Please contact the Primary Industry Training Organisation standards@primaryito.ac.nz if you wish to suggest changes to the content of this unit standard.