25126 Demonstrate knowledge of hydraulics and pump types ...



|Title |Demonstrate knowledge of hydraulics and pump types and fittings for on-site domestic wastewater treatment systems |

|Level |4 |Credits |6 |

|Purpose |People credited with this unit standard are able to, for on-site domestic wastewater treatment systems,|

| |demonstrate knowledge of: the properties of wastewater, flow rate, and pressure of liquids; water |

| |velocities and determine flushing velocities; pressure loss in pipe systems and associated |

| |calculations; orifice flow; pump types and performance; pipe types and pipe fittings, and the |

| |installation of pipes; and calculate system operating point to match a system curve to a pump |

| |head-discharge curve. |

|Classification |Water Industry > Wastewater Treatment |

|Available grade |Achieved |

Guidance Information

1 The standards applicable to this unit standard are:

AS/NZS 1260:2009 PVC-U pipes and fittings for drain, waste and vent applications;

AS/NZS 2033:2008 Installation of polyethylene pipe systems;

AS/NZS 2566.2:2002 Buried flexible pipelines – Installation;

AS/NZS 4130:2009 Polyethylene (PE) pipes for pressure applications;

NZS 7643:1979, Code of practice for the installation of unplasticised PVC pipe systems;

All standards are available from .

2 Credit for this unit standard does not qualify the candidate to work in a drainlaying situation that comes under the drainlayer’s licence requirements issued under the Plumbers, Gasfitters, and Drainlayers Act 2006 and any subsequent amendments.

Outcomes and performance criteria

Outcome 1

Demonstrate knowledge of the properties of wastewater, flow rate, and pressure of liquids.

Performance criteria

1.1 Wastewater is described in terms of density, specific weight, and viscosity.

Range units – metric, imperial.

1.2 Flow rate is described and calculated for specified wastewater system components.

Range components – treatment units, distribution methods, land application systems.

1.3 Pressure of liquids on tank wall during compartment pumpout is described and calculated for specified wastewater treatment systems.

Outcome 2

Demonstrate knowledge of water velocities and determine flushing velocities.

Performance criteria

2.1 Water velocities are described in terms of the significance of maximum and minimum values.

2.2 Flushing velocities for pipe cross-sections and flow rates in wastewater are determined using the continuity equation.

Outcome 3

Demonstrate knowledge of and calculate pressure loss in pipe systems.

Performance criteria

3.1 The Bernoulli equation is described in terms of the conservation of energy.

3.2 Pressure loss is described in terms of its relationship with pipe specifications and flow dynamics.

3.3 Pressure loss is calculated for pipe fittings used in on-site wastewater systems according to manufacturers’ specifications.

3.4 Hydraulic grade lines (HGL) and total energy lines (TEL) are described in relation to on-site wastewater system configurations.

Range steady flow in pipelines, diminishing flow pipeline (distribution manifold in sand filter); low-pressure effluent dosing (LPED) configuration, drip irrigation configuration.

Outcome 4

Demonstrate knowledge of orifice flow in relation to on-site domestic wastewater systems.

Performance criteria

1. Orifice flow is described in relation to water and its subsequent application to wastewater treatment and land application.

Range includes but is not limited to – distribution manifold in sand filter, LPED trench system.

Outcome 5

Demonstrate knowledge of pump types and performance.

Performance criteria

5.1 Pump types and their control are described in terms of their suitability for on-site wastewater systems.

Range pump types – positive displacement (piston, helical rotor), centrifugal, single stage, multi stage, submersible, surface mounted, self priming;

pump control – probes, floating switch, pneumatic control, timer control, programmable logic controller (PLC).

5.2 Pump performance is described in terms of head-discharge characteristics, energy requirements and efficiency, and suction capacity.

Outcome 6

Calculate system operating point to match a system curve to a pump head-discharge curve.

Performance criteria

6.1 Calculation of system operating point matches a system curve to a pump head-discharge curve.

Outcome 7

Demonstrate knowledge of pipe types and fittings, and the installation of pipes for on-site wastewater treatment and land application systems.

Performance criteria

7.1 Pipe types are described in terms of their features and manufacturer’s specifications for use in on-site wastewater treatment and land application systems.

Range pipe types – polyethylene, PVC, slotted;

features – pressure rating; high, medium, low density; internal and nominal diameter.

7.2 Pipe fittings used for on-site wastewater systems are described in terms of their functions and purpose.

Range sequencing and indexing valves, filters, flush valves, check valves, air valves, vacuum breakers, saddles.

7.3 Pipe system installation is described in terms of trenching and bedding requirements, and commissioning.

Range trench dimension, backfill, use of geofabrics, safety requirements.

7.4 Pipe system installation is described in terms of the situations where engineering advice is required.

Range evidence is required for at least three situations.

This unit standard is expiring. Assessment against the standard must take place by the last date for assessment set out below.

Status information and last date for assessment for superseded versions

|Process |Version |Date |Last Date for Assessment |

|Registration |1 |17 October 2008 |31 December 2018 |

|Rollover and Revision |2 |16 February 2017 |31 December 2022 |

|Review |3 |23 July 2020 |31 December 2022 |

|Consent and Moderation Requirements (CMR) reference |0101 |

This CMR can be accessed at .

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