How it works
Grease arrestors are designed to keep as much fat oil and grease (FOG) as possible out of the sewerage system to minimise blockages and odours. A grease arrestor cools waste allowing FOG to separate and float to the surface of the trap. Some solids may settle at the bottom of the arrestor as sludge.
Maintenance
Clean your grease arrestor regularly by using a Cassowary Coast Regional Council-approved liquid waste contractor. There is a list of approved contractors at the bottom of this section. This will help reduce odours and prolong the life of the arrestor. A correctly-sized arrestor will need cleaning every eight to 12 weeks. Recommendations for cleaning times are listed on your Trade Waste Permit.
Keep vents, lids, frames and concrete surrounds in good order. Poorly-fitted or damaged vents, lids and frames may allow odours to escape or vermin to breed. Public safety and the infiltration of rainwater are also major concerns.
A hose tap needs to be installed within five metres of the grease trap. This hose tap needs to be used for grease trap cleaning purposes only. A backflow prevention device (double-check valve) needs to be installed immediately prior to the hose tap.
Recycle all spent cooking oils
Do not dispose of unwanted oil and grease through your arrestor. This will adversely affect the quality of effluent discharged to the sewer and you will need to service your arrestor much more frequently. Most cooking oils are suitable for recycling.
Grease arrestor requirements
Do not discharge garbage grinder or hairdresser waste through your grease trap.
Do not attempt to clean your grease arrestor yourself.
The use of solvents, enzymes, mutant bacteria, odour control units or pesticide in grease arrestor traps is prohibited unless specifically approved by the trade waste officer.
The maximum allowable capacity of an individual grease arrestor is 2000 litres. Where the capacity requirements for a premise are greater than 2000 litres, additional arrestors shall be used, with each arrestor to be a discrete installation separately treating a defined waste stream. The minimum size grease arrestor allowable in a commercial situation is 550 litres.
Grease convertors and big dippers are not allowed.
In-sink bucket trap and in-floor bucket trap
Install an authorised in-sink bucket trap and in-floor bucket trap in food preparation and handling areas.
Oil arrestors
Oily waste water can interfere with the operation of Council's sewerage system, have an impact on the wastewater discharged to the environment and affect the health of people working on the sewerage system.
In-ground triple-chamber-type oil arrestors are no longer permitted for oil and grease separation. Oil arrestors need to be the coalescing plate type, vertical gravity arrestors, hydro-cyclones or other Cassowary Coast Regional Council-approved devices.
Oil arrestor pumps
Only non–emulsifying pumps such as an electrically-driven diaphragm pump (at less than 40 cycles per minute) or a mono pump may be used to pump the wastewater to an arrestor. The pump discharge must not be greater than the capacity of the arrestor.
Any person wishing to sell an oil arrestor system which includes the pump for treatment of wastewater going to sewer must conform to these guidelines.
Bunding
The area around all treatment installations must be bunded. There must be no spillage or overflow of trade wastewater influent or effluent, sludge or treatment chemicals to the stormwater or sewerage systems (by gravity or by automated mechanical means).
Ensure that the oil separator is inside a bunded area.
Installation requirements for oil arrestors are as follows:
- Only Council-approved equipment is to be installed
- Installation must comply with relevant Council building and plumbing by-laws
- Minimum capacity: 1000 litres per hour
- Where required, pumps are to be sized so as not to exceed the capacity of the arrestor
- Only approved non-emulsifying pumps are to be used
- Sludge outlet to be fitted with a full-flow valve
- Manufacturers' recommended servicing/clean schedules must be adhered to
- Servicing records are to be kept and made available to trade waste officers
- Cleaners and detergents must be of "quick break" formulation
- Sludge container and an oil container must be placed under the sludge and oil outlet pipes.
N.B. In-ground oil arrestor grease silt traps are no longer acceptable.
A permit to undertake plumbing work must be obtained from Council prior to installation.
All work needs to be performed by a licensed plumber/drainer.