WSA02 - Gravity Sewer

What is a Branch Sewer?

DN375 to DN600 that connects reticulation sewer, or a sewer of any diameter that joins another sewer line.

What is a boundary trap area?

Area within which properties connected to a sewer are potentially at risk of back vented gases and where boundary traps are usually required to be installed as a preventative measure

What are back vented gases?

Gases that occur when pressure imbalances or blocked roof vents, force harmful sewer gases like methane and hydrogen sulphide back through plumbing fixtures instead of safely releasing them outdoors

What is the Australian Height Datum (AHD)?

A level datum derived from main sea level observations at 30 Tide gauge locations located along the Australian coastline

What is a Boundary Trap?

An inverted siphon trap installed in a customer sanitary drain to prevent sewer gas passing and entering the building through the drain. See also water seal.

What is a bulkhead?

A structural partition across a pipeline trench built to minimise longitudinal and lateral movement of the pipeline to minimise ground movement in the trench and to restrict movement of fines within along the trench caused by infiltration and ground water flow through the embedment and trench fill materials.

What is Cathodic protection?

Protection of a metal from corrosion by making it the cathode, using either galvanic or impressed current.

It is usually applied to mitigate external corrosion of electrically continuous welded steel buried pipelines and internal corrosion of welded steel service reservoirs.

What is a Cathode?

The electrode where reduction takes place and electrons are gained in an electrical device

What is an Electrode?

What are the two main types?

What are common uses?

A electrical conductor used to make contact with a non-metallic part of a circuit such as an electrolyte, a semiconductor or air. Electrodes let electricity enter or leave a substance. They act as sites for oxidation (loss of electrons) and reduction (gain of electrons) in chemical reactions

The two types of electrode are an Anode (Oxidation) or a Cathode (Reduction)

Batteries: They move electrons through a circuit

Medical devices: Sensirs like ECG/EKG pads stick to skin to read electrical impulses from the heart.

Welding: Metal rods use electricity to melt and join pieces of metal together

How many drawings are in SEQ Gravity Sewer Standard Drawings

131

What is a conversion slab?

A maintenance whole component which, in the horizontal plane, reduces the diameter of the maintenance hole from that of the shaft to dimensions approximating that of the entrance opening

What is a cowl?

A hood shaped covering of a Ventilation shaft

What is a customer sanitary drain?

A pipeline installed by a plumber within the property boundary and operated by a property owner to convey sewage from buildings to the property connection point. also called a house drain, House service line, house sewer, sanitary connection, property drain, sanitary drain

What is Design Flow in Sewer?

What does PDWF,GWI and RDI stand for?

The estimated maximum flow into a sewer comprising the sum of peak dry weather flow groundwater infiltration and peak rainfall dependent flow and infiltration.

PDWF = Peak dry weather flow

GWI = Ground water infiltration

RDI = Peak rainfall dependent inflow and infiltration

What is a drop junction?

A fitting, usually of a tee configuration, used in the pipework of drop structures and vertical risers

What does ERS stand for and what is its function?

Emergency relief structure. it is a directed overflow structure designed to permit controlled discharge of sewage that exceeds downstream system capacity. this failure may be caused by blockage collapse, etc. also called an overflow structure.

What is an end of line sewer? What is another name for it?

Permanent upstream end of the reticulation sewer. Also called a dead end sewer

What does EP stand for? What is it?

Equivalent Population. It is the equivalent hypothetical residential population that would produce the same peak dry weather flow as that contributed by the area under consideration. For example, all zoning including residential commercial and industrial.

What does ET stand for?

Equivalent Tenement. It is the equivalent hypothetical residential dwellings that were produced the same peak dry weather flow as that contributed by the area under construction. For example, all zoning including residential commercial and industrial.

What is exfiltration of Sewer?

Escape of sewage from sewer into the surrounding ground.

What is a receptacle?

A container or hollow object used to hold, store or receive things

What is Froude’s Number (Fr)?

A dimensionless number defined as the ratio of a characteristic velocity to a gravitational wave velocity. For shallow water waves, like for instance a hydraulic jump, the characteristic velocity (V) is the average velocity, averaged over the cross-section perpendicular to the flow direction. The wave velocity (C) is equal to the square root of gravitational acceleration (g), times cross-sectional area (A), divided by free-surface width (B).

Is there two types of gravity sewers?

Yes

Pressurised system: Pipeline operates full

Non-pressurised system: Pipeline operates partially full

What is head?

How do you convert head to KPa?

Head is the pressure expressed in terms of the height of a column of water infiltration RDI metres.

Head is a factor of 9.81 (usually taken as 10) lower than the equivalent value in KPI

Therefore, 10 m equals 100 kPa

What is an Inclinometer? What are other words for it?

An instrument for measuring angles of slope, elevation or depression of an object with respect to gravity.

Also known as a pitch and roll gauge, tilt meter and clinometer

What does HGL stand for? What is it?

It stands for hydraulic grade line and it is a line/hydraulic profile indicating the piezometric level of flow at all points along a conduit open channel or stream.

In pipes under pressure each point on the hydraulic profile is an elevation expressed as the sum of the height associated with the pipe elevation and the pipe pressure (head).

What is a Manometer?

Manometers are Piezometers that can be used to measure pressure in Gas Pipelines as well.

What is a Manometer?

Manometers are Piezometers that can be used to measure pressure in Gas Pipelines as well.

Is Inflow an infiltration the same thing in a sewer system?

No

Infiltration is the ingress of groundwater into a solar system

Inflow is the ingress of stormwater into a sewer system

What is a inverted syphon?

A pipe where the soffit drops below the hydraulic gradient and in which the sewage flows under pressure of gravity

What is a soffit in pipework?

The highest point of the internal surface at any given cross-section

Also known as the obvert.

What is a lamphole?

A maintenance structure, typically with DN375 concrete shaft, which ceased to be constructed in the early 90s. These are no longer accepted.

Is coating and lining the same thing?

Yes

What are the three types of sewer maintenance structures?

How are they different?

1. Maintenance chamber - <DN225 base channels, shaft size from DN450 to DN900 w/ a removable cover for inspection but no entry.

2. Maintenance hole - >DN900 shaft w/ >DN600 access opening. “Manhole”

3. Maintenance shaft - <DN225 base channels, shaft size from DN225 to DN450 w/ a removable cover for inspection but no entry.

What is a manufactured bend?

A PVC bend, post-formed from solid wall PVC-U pipe complying with AS/NZS1260, with a fixed length and radius and a socket and spigot configuration.

what is nominal size (DN)?

An alpha numeric designation of size for components of a pipeline system, which is used for reference purposes; it comprises the letters DN followed by a dimensionless whole number which is indirectly related to the physical size , in millimetres, of the bore or outside diameter of the end connections, depending on pipe material. Where the code does not specify pipe material, DN shall be taken as nominal bore.

For example, DN300 may refer to DN300 uPVC or DN315 PE

What is NuSewer?

A type of Smart Sewer that comprises fully welded PE pipes fittings and maintenance shafts that is mandatory for QUU and a permitted option for Unitywater.

What is overlay?

The zone between the side support and either the trench fill or the embankment fill.