A new technology for commercial kitchens increases the efficiency of wastewater disposal and relieves pressure on wastewater treatment plants and pumping stations. Callum Fitzpatrick reports.

When it comes to commercial kitchens, many restaurants and eateries opt to install an underground grease trap to treat waste. This is usually a simple technology with a vertical baffle arrangement to separate fats, oils and grease (FOGs) from effluent wastewater.

However, these systems are often inefficient and require frequent pump-outs. If these pump-outs aren’t initiated, the FOGs travel downstream and foul critical downstream pumping stations, which results in higher maintenance costs for the local water authority.
A popular alternative is to use enzymes to ‘digest’ FOGs – a preference for many convenience stores and fast food outlets. However, enzymes are an expensive solution and often simply transfer the problem to a local river or stream.

That’s why Comcater has introduced the GreaseShield. This proactive mechanical grease trap takes advantage of waste thermal energy present in effluent being discharged from commercial kitchens to remove emulsified FOGs before they are able to solidify.

GreaseShield product specialist Con Krousoratis says the technology was introduced as a direct response to blocked pipes in commercial and industrial kitchens.

“FOGs are the main causes of blocked pipes in commercial kitchens. They’re essentially the by-products of food preparation and washing up activity, therefore the main grease generators are pre-rinse and pot washing sinks. If these are not managed efficiently they can clog the pipes (regardless of the size) just like fats can build up in your body and cause a blockage in your arteries,” Con says.

“The GreaseShield dewaters food waste and removes FOGs from the wastewater into containers that are easy to remove and empty. This means that there is no requirement for kitchen staff to access the inside of the GreaseShield.

“Without the GreaseShield in commercial kitchens, FOGs will cause blockages and foul odours if untreated, not to mention the pollution of local water resources.”

GreaseShield uses a combination of retaining baffles, reverse flow configuration and the differing specific gravities of water and FOGs which are complemented by thermal layers within the effluent. All of these factors, working in conjunction with the properties of the oleophilic and hydrophobic FOG removal aids in protecting drainage systems.

Currently, in most businesses, pre-treatment is required before it is discharged to sewerage. Each enterprise will have its own requirements for pre-treatment. Many take-away food businesses, for example, will require a grease and oil interceptor. This traps grease and oil at the source, preventing it from entering the sewerage system where it may cause blockages.

“GreaseShield works to remove and dewater organic solid matter that is typically entrained in the effluent. This prevents anaerobic foul smelling conditions brought about by biological activity, depleting dissolved oxygen present in the effluent,” Con adds.

Grey effluent is recovered from the outlet and recirculated back to the inlet of the GreaseShield. This prevents the build up of fine sedimentation in the tank and increases efficiency.

“The GreaseShield also has an automated final effluent recirculation feature that processes the final effluent three times every five minutes during the FOG removal operation. This ensures only the highest compliant effluent discharges,” Con explains.

“The final effluent recirculation feature also agitates and cleans the tank, preventing the build-up of fine sedimentation.”

The pulsing action of the final effluent recirculation feature ensures that the FOGs are directed and removed by the FOG drum ensuring a high efficiency removal and preventing FOG and creams breaking down and becoming an odour nuisance within the GreaseShield.

The automated self cleaning function eliminates the recurring need to pump grease traps, refill with clean water, and eliminates the costly use of biological agents and chemicals.

“GreaseShield does not smell in operation because it removes organic matter and FOGs typically entrained in the heated effluent that leaves a commercial kitchen, thus inhibiting the biological degradation of organic matter in effluent and eliminating the conditions under which anaerobic conditions prevail,” Con says.

Con adds that the technology also presents a sustainable method of waste removal.

“GreaseShield reduces CO2 emissions and avoids the loss of a renewable energy source caused by pumping out grease traps. It also protects the environment by protecting the drainage and watercourse systems,” Con says.

“FOGs collected from the GreaseShield should be stored in a secure bunded facility prior to being collected by authorised waste collectors with appropriate permits. The collection details, including the amount of FOGs being collected, should be recorded in a manifest record for audits by the relevant authorities. Environmental Products and Services also offer a collection service as part of our managed solutions package.”

The good news for plumbers is that installation of a GreaseShield is much quicker and simpler than more traditional solutions.

“We estimate that the installation of a GreaseShield system is around one or two hours, compared to the several days that can be expected for large in-ground grease traps which require excavation works and delays to the kitchen and business,” Con says.

“An accredited plumber is required to install the system in line with the local trade waste policy for the respective water authority and council. It also places plumbers in a strong position, enabling them to offer a cost-effective solution with a much smaller footprint.”