The function of a grease trap is to reduce the presence of fat, oil and food scraps in the trade waste stream.

How a grease trap operates:

1. Wastewater enters the grease trap and over time:
   • Cools down, allowing fats and oils to rise to the top
   • Food scraps sink to the bottom
   • Wastewater clear of fats, oils and food scraps exits the grease trap into the sewer.
2. Fats, oils and food scraps collected by the grease trap need to be periodically sucked out by an EPA licenced waste transporter who also cleans the inside of the empty grease trap
3. Odourless operation because they must be air tight and only vented to free air

All fixtures in food preparation areas are required to be plumbed into the grease trap such as:

• Dishwashers
• Sinks
• Hand basins
• Floor drains
• Bin wash areas
• Cleaners sinks

Grease traps are commonly used on trade waste streams produced by food handling businesses (e.g. hot chicken sales, cafes, restaurants, function centres, food manufacturers).

Food and oil interceptor - ABOVE GROUND

Food and oil interceptor - BELOW GROUND

The function of a marble chip acid neutralising tank is to reduce the presence of an acidic trade waste stream by neutralising it. 

Marble chip acid neutralising tanks are commonly used on trade waste streams produced by small laboratories (e.g. school laboratories). 

Marble chip acid neutralising tanks are not suitable for trade waste streams containing sulphuric acid as it creates a layer of calcium sulphate on the chips which is a barrier to further neutralisation of the acid. 

YVWCD-2-6589 Marble Chip Acid Neutralising Tank

The function of a mixing tank is to reduce the concentration of each trade waste component by mixing. Mixing tanks are commonly used on small volumes of trade waste streams produced by printing processes and photographic processing.

YVWCD-2-6598 Mixing Tank

The function of a petrol and oil interceptor is to reduce the presence of petrol and petrochemical oils in the trade waste stream. Petrol and oil float after the trade waste has had sufficient time to separate inside the interceptor. Remaining wastewater is what the interceptor discharges to sewer. 

Petrol and oil interceptors are commonly used on trade waste streams produced by petrol stations, mechanical repair workshops, engine/part washing and car/truck washes.

Petrol and oil interceptors at car/truck washes usually have waste water treated by a silt pit discharging into them for further treatment prior to discharging to sewer, see “silt pit”. 

YVWCD-2-6597 Petrol and Oil Interceptor

The function of a settling tank is to reduce the presence of solid particles (e.g. silt, plaster and stone grindings) in the trade waste stream. Solid particles sink to the bottom of the tank after the trade waste has had sufficient time sitting inside the tank. Remaining wastewater is what the tank discharges to sewer.

Settling tanks are not suitable for food processing/preparation trade waste streams as the tank is likely to produce odour in that application. For food processing/preparation trade waste streams, see “grease traps”.

Settling tanks are commonly used on trade waste streams from plaster sinks, soil laboratory sinks and construction sites.

YVWCD-2-6596 Settling Tank

The function of a silt pit is to reduce the presence of solid particles such as dirt, grit, sand and broken glass in trade waste by straining and settling them out of the waste stream.

The strainer reduces the presence of solid particles in trade waste by straining them out of the waste stream. The pit reduces the presence of particles small enough to pass through the strainer by allowing them to sink to the bottom of the pit after the trade waste has had sufficient time sitting inside the pit. Remaining wastewater is what the pit discharges to sewer.

Silt pits are commonly used on trade waste streams containing significant volumes of solids (e.g. car washing, bottle washing, truck washing).

Silt pits usually discharge to a petrol and oil interceptor at car/truck washes prior to discharging to sewer, see “petrol and oil interceptor”.

Silt pits are not suitable for food processing/preparation trade waste streams as the pit is likely to produce odour in that application. For food processing/preparation trade waste streams, see “grease traps”.

The bucket and pit must be emptied of the collected solids periodically to prevent blockages.

YVWCD-2-6595 Silt Pit

The function of a silt trap is to reduce the presence of debris and silt in trade waste by straining them out of the waste stream.

Silt traps are commonly used on trade waste streams of car washes to remove debris and excessive silt prior to entering a petrol and oil interceptor.

The bucket filtering the solids must be emptied of the collected solids periodically to prevent blockages.

YVWCD-2-6594 Silt Trap

The function of a solvent and oil interceptor is to reduce the presence of solvents and oils in the trade waste stream. Solvents and oils float after the trade waste has had sufficient time to separate inside the interceptor. Remaining wastewater is what the interceptor discharges to sewer.

Where the interceptor is to be located below ground a Petrol and Oil Interceptor must be installed.

Solvent and oil interceptors are commonly used on trade waste streams from laboratory sinks, small troughs for parts degreasing, and silk screen printing.

YVWCD-2-6593 Solvent & Oil Interceptor

The function of a straining pit is to reduce the presence of solid particles such as lint and hair in trade waste by straining and settling them out of the waste stream.

The strainer reduces the presence of solid particles in trade waste by straining them out of the waste stream. The pit reduces the presence of particles small enough to pass through the strainer by allowing them to sink to the bottom or float to the top of the pit after the trade waste has had sufficient time sitting inside the pit. Remaining wastewater is what the pit discharges to sewer.

Straining pits are commonly used on trade waste streams of laundries, laundrettes and vets.

Straining pits that are used in applications where the trade waste needs to be cooled down to ensure its below 38C (such as laundries) can be sized so that the pit retains the water for a minimum of 1 hour to cool the trade waste down prior to discharging to sewer.

Straining pits are not suitable for food processing/preparation trade waste streams as the pit is likely to produce odour in that application. For food processing/preparation trade waste streams, see “grease traps”.

The bucket and pit must be emptied of the collected solids periodically to prevent blockages.

YVWCD-2-6592 Straining Pit

The function of a test sump is to facilitate trade waste sampling.

Test sumps are required where it is unfeasible for samples to be taken from the outlet of trade waste treatment equipment or an overflow grate on the disconnector gully or when otherwise required by YVW. 

YVWCD-2-6588 Test Sump