Why a FOGFILTER unit is required

When fog is contaminated  by detergents, dairy/ice cream/milk shakes, cleaning products with surfactive properties /surface-active materials it  can’t be efficiently separated by most good GRU /GAD technologies. Once this fog enters into suspension, it simply cannot separate in the short time it would normally pass through a GRU/GAD system. These GRU and GAD systems are designed to separate during fast flow rates , usually between 0.75 litres per second to 3.15 litres per second.

Put simply, once fog is contaminated and goes into suspension, It becomes heavier than water and rather that float on the water to be separated, it sinks and stays mixed throughout the water for 3 days or more. This is why a GRU or GAD requires a polishing filter /cartridge to catch this fog that is deep in emulsion.


Typical sources for these emulsifiers within the  FSE are :

Milk Shakes
Frozen Dairy
Hot dairy based drinks/beverages, latte coffee and others
These products have varying effects on the waste stream /waste water depending on type of dairy product. A dairy Curd can form which is separated settled or floated phase of dairy products comprised of proteins and fats which form as a result of Calcium Phosphate at ZPC pH suspended or emulsified in the waste stream. The densities float or precipitate in various measure which can affect a GRU/GAD process.

Combi Ovens:

Combi ovens are widely used to cook delicious food. These ovens require regular cleaning where detergents are used to clean them to standard. This waste stream is then usually channelled via the GRU / GAD unit with a lot of fog in suspension. This fog is then separated in the GRU/GAD and any trace fog in suspension is captured in the Fogfilter polishing unit attached to it.

Mop Drop Sink:

Many FSE’s have a Mop drop sink for the janitorial waste water from the mop bucket. Because of Health and Safety issues, most FSE’s require the use of the very best Shop/Kitchen floor degreasers. The volume of fog may be low in this waste stream but this is often very high in emulsifiers which suggests that the fog content is in deep suspension. This effluent is often high in silt picked up by the mop and this silt can cause significant disruption to any GRU /GAD. The reason for this significant disruption is that when large amounts of silt enter a typical GRU/GAD , the volume of the separation section of these units is reduced as the silt builds up within the unit. This can effectively change what is referred to as the PDI design parameters of these GRU/GAD technologies.


Dishwashers in FSE’s generally have a low but not insignificant fog contamination in the waste stream. Prior to the fogfilter invention, there was no alternative other than discharging this effluent via the GRU/GAD. This option while helping the FSE achieve their discharge consent standard, also can have a negative impact on the GRU/GAD process for the same reasons outlined throughout. Emulsified fog can cause significant disruption to any finely tuned separation process.


Some FSE’s require an inhouse washing machine for uniforms and/or cleaning cloths. These items can often be heavily contaminated and leave the washing machine in suspension. Fogfilter technology can be used on a stand alone basis to allow the clean water to discharge to the drain with the fog retained. The changing schedule of the Fogfilter cartridge will depend on the amount of fog pollutants. Some FSE’s may have minimal fog in the waste stream from the washing machine, while others may have more significant amounts. This waste is often high in surfactants from the detergents used. The benefits of Fogfilter on a washing machine is that this waste stream can also the be routed away from the GRU directly in to the drain.

Like Milk waste, the GRU /GAD technologies differ from one producer to another so it is difficult to cover the exact effect on each technology. Fogfilter takes the guessing out of this by helping the FSE to reduce the volume of silt that enters the GRU/GAD.

Fogfilter offers a simple solution. We advise the FSE to install a custom made stainless steel mesh basket within the Mop Drop sink to offer primary separation of the silt Reduce the volume of silt and surfactants that enters the GRU / GAD . This silt could be regularly scooped out of this mesh basket to prevent  it quickly clogging up a Fogfilter unit or GRU/GAD unit. It is always simpler to separate waste at source. The waste stream is then routed via the stand alone Fogfilter unit and the clean waste effluent discharged safely to the receiving drain fog free and within the FSE’s Discharge Consent.

The waste stream can either be routed through the GRU with a bolt on fogfilter unit or via a stand alone fogfilter unit with a direct discharge to the main drain . The advantage of using a stand alone fogfilter unit on a mop drop sink is that the hydraulic load is reduced to the GRU / GAD  when the mop drop waste stream is safely discharged to the main drain fog free. This will enhance the operation capabilities of the GRU / GAD.

If you would like to know more about sourcing Fogfilter technology please contact us using the enquiry form below. We look forward to building a strong network of Distributors to meet the requirements of FSE’s internationally.

The Fogfilter patented technology is designed to make it much simpler for Food Service establishments (FSE’ s) to meet and exceed their discharge consent standards.