Plumbing for Retail Food Businesses
Food outlets produce waste such as cooking oil, grease and food solids every day. Waste that
is discharged directly into Flow Systems’ sewer can cause blockages, overflows and overload
the wastewater treatment plant. By correctly installing grease traps and similar devices,
plumbers can help retail food businesses manage and dispose of greasy wastewater.
Grease traps – important information about installation and maintenance
If you cook or serve hot food, Flow Systems requires you to install a grease trap and have a
trade waste agreement in place.
1. Wastewater from food preparation areas, kitchen sinks, dishwashers, floor wastes and
garbage areas should all flow to your grease trap.
2. Install grease traps as close to the source of grease as possible, to ensure that pipes
between the kitchen and the grease trap don’t get clogged with grease. If you can’t avoid
long pipe runs, such as in shopping centres, your plumber can increase the grade or use a
heat trace.
3. Grease traps should drain by gravity to the sewer. If this is not possible, the grease trap
should drain to a pump well, and wastewater should be pumped to the sewer from there.
It is important not to choose this option for convenience, since it is more difficult
and expensive to manage.
4. Potato peelings contain starch rather than grease, so wastewater from potato peeling
machines should not be directed to a grease trap.
5. The fat and oil from barbecuing must be collected for recycling. It must not drain directly to
a grease trap or the sewer.
6. Only authorised grease traps are permitted to be installed. Please refer to authorised pretreatment listings in our “Trade Waste” section on your community website.
Venting grease traps
An important requirement of the pre-treatment installation is venting the grease trap. The
venting pipework must be 100 mm diameter minimum. Your plumber is not permitted to use air
admittance valves to vent grease traps.
Inlet and outlet pipework
Inlet and outlet pipework for grease traps is covered in the applicable plumbing and drainage
codes and standards and this work is inspected by the NSW Department of Fair Trading. It is
not part of pre-treatment and does not come under the jurisdiction of Flow Systems.
Plumber’s Certificate of Compliance
When a grease trap is installed, Flow Systems requires a Certificate of Compliance for the
work. Hire a licensed plumber to install your grease traps and obtain a Certificate of
Compliance for this work.
Maintaining grease traps
Do not install other services, such as air conditioning ducts, where they will block access to the
grease trap lid. The space above the grease trap must be at least equal to the depth of the
grease trap. This allows enough space to monitor the grease trap, remove the lid, maintain it
and get it pumped out.
Preferable drainage layout for a grease trap installation
Access for grease trap waste collection tankers
To ensure that they can service grease traps easily, contractors must be able to park as near
as possible to a grease trap. Contractors do have long suction hoses to access the traps, but it
is always better to be closer.
Floor and sink waste bucket traps
In all commercial kitchens and food preparation areas, authorised in-sink and in-floor waste
bucket traps must be installed.
In-floor bucket trap
In-sink bucket trap
Fixed pump-out lines
A fixed pump-out line may be installed to enable future servicing of grease traps. Note that
these are not part of the pre-treatment and are not specified by Flow Systems. Installing a fixed
pump-out line may require council approval. Consult a grease trap waste contractor if you
intend to install a fixed pump-out line.
A fixed pump-out line must be as straight as possible. If bends are required, use long radius
bends. Lines should be a minimum diameter of 75 mm in a robust material, such as galvanised
iron. Fixed pump-out lines should terminate near the grease trap but not in it, as a flexible line
needs to be attached to ensure all of the waste is collected from inside the trap. To prevent
odours when the lines are not in use, the lines require cam-lock fittings at both ends to the
pump-out contractor’s specifications as well as caps for the cam-lock fittings.
Cleaning grease traps
To avoid spills, smells and polluted wastewater, grease traps must be pumped out regularly.
When grease traps are pumped out, the contractor will also need to clean the grease trap’s
internal surfaces, and may need to scrape the inside of the trap. There is no requirement to
completely refill the trap. Flow Systems will specify how often your grease trap needs to be
pumped out, depending on the size of your grease trap and the amount and quality of greasy
wastewater your business generates.
Flow Systems manages scheduling, collecting, transporting, and disposing of grease trap
waste.
Managing waste oil
Grease traps are designed to treat greasy wastewater and are not designed to have waste oil
tipped into them. Waste oil should never be poured down the drain or into your grease trap.
Instead, collect waste oil from deep frying and BBQs, store it in sealed containers in a properly
bunded area and request an oil recycler to collect it.
Multiple grease traps
If you manage a shopping complex or small shopping centre, you may have multiple grease
traps. Grease traps must be big enough to treat all the wastewater from all of the businesses
that use them. If not, you must upgrade.
Centralised pre-treatment for shopping centres
If you need more than 45,000 litre grease trap capacity, you must install centralised
wastewater treatment, such as dissolved air flotation (DAF). DAF separates grease and light
suspended solids from wastewater by floating them to the surface on fine air bubbles.
Boundary trap
On all retail food properties with a gravity connection to the sewer, a boundary trap must be
installed. If the property does not have a boundary trap and the customer has applied for a
trade waste permit, the customer is responsible for installing a boundary trap at the boundary
or the point of connection.
Disconnecting a grease trap
If your business process changes to one where you no longer discharge trade wastewater to
the sewer, contact Flow Systems to cancel your permit and disconnect your grease trap(s)
from the sewer.
Flow Systems will arrange for a licensed grease trap transporter to empty the trap before it is
disconnected. A licensed plumber will put a pipe through or around the grease trap (from inlet
to outlet) and fills it with sand or blue metal.
Repairing or replacing a grease trap
Grease traps tend to have a fairly long lifespan, but over time they can wear out and become
hard to clean. In certain cases they may develop holes and start to leak. It can be very difficult
to repair some materials that have contained grease for many years, and in these instances it
may be better to replace them completely.
Backflow prevention
Your plumber should ensure you have adequate backflow prevention. It is important to hire a
backflow accredited licenced plumber and arrange to install and test a backflow containment
device(s) at the property boundary adjacent to the water meter(s) servicing your property.
Your plumber must also install a tap within five metres of any pre-treatment equipment (e.g.
grease trap) and a backflow prevention device on the inlet side of the tap.
Minimum Pre-treatment requirements for Retail Food Processes
Commercial Processes
Cafeteria, Canteen (& School Hot Meals)
Take-Away Incl Fish & Chips, Hot Chicken
Wastesafe Only, Incl School Dom Science
Snack Bar - Coffee Lounge - Hot Foods
Restaurant, Food Court
Restaurant, Food Court
Restaurant, Food Court
Restaurant, Food Court
Restaurant, Food Court
Restaurant, Food Court
Kitchen - Hospital, Nurses Home
Kitchen - Hospital, Nurses Home
Kitchen - Hospital, Nurses Home
Kitchen - Hospital, Nurses Home
Kitchen - Hospital, Nurses Home
Kitchen - Hospital, Nurses Home
Kentucky Fried Chicken
McDonalds Restaurants
Pizza Hut
Function Centre
Function Centre
Function Centre
Function Centre
Function Centre
Function Centre
Red Rooster Chicken
Delicatessen With Hot Food <12kl/Day
Hungry Jacks
BBQ Wholesale
(Chicken)
Seats/Beds
1-69
70-199
200-399
400-599
600-799
800-1000
1-69
70-199
200-399
400-599
600-799
800-1000
Discuss with
Flow Systems
1-69
70-199
200-399
400-599
600-799
800-1000
Discuss with
Flow Systems
BBQ Wholesale
(Pork, Duck)
Discuss with
Flow Systems
BBQ Restaurant
Discuss with
Flow Systems
W/Sale Food<12kl/Day
Minimum
Pre-Treatment
1000 L
1000 L
1000 L
1000 L
1000 L
1500 L
2000 L
3000 L
4000 L
5000 L
1000 L
1500 L
2000 L
3000 L
4000 L
5000 L
1500 L MIN
1500 L – 3000 L
1000 L
1000 L
1500 L
2000 L
3000 L
4000 L
5000 L
1500 L
1000 L
1500 L
1500 L plus grease
removal device
upstream of grease
trap
2000 L plus grease
removal device
upstream of grease
trap
2000 L plus grease
removal device
upstream of grease
trap
1000 L
In-floor and
in-sink
Bucket Traps
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Commercial Processes
Hotel / Motel Kitchen
Hotel / Motel Kitchen
Hotel / Motel Kitchen
Hotel / Motel Kitchen
Hotel / Motel Kitchen
Hotel / Motel Kitchen
Ice Cream Parlour
Butchers - Retail
Fish (Fresh Outlets) No Cooking
Chicken (Fresh Outlets) No Cooking
Small goods <12kl/Day Maximum
Wholesale Butcher <12kl/Day Maximum
Bakery Retail – Hot Bread – Cakes
Bakery Retail – Pies – Sausage Rolls
Ice Cream Parlour
Seats/Beds
1-69
70-199
200-399
400-599
600-799
800-1000
600-799
Minimum
Pre-Treatment
1000 L
1500 L
2000 L
3000 L
4000 L
5000 L
No grease trap
1000 L
Large basket trap
with fixed screen and
removable basket
1000 L
1000 L
1000 L
No grease trap
1000 L
4000 L
In-floor and
in-sink
Bucket Traps
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes