Patent Description:
Wastewater FOG is produced, e.g., by meat fats in food scraps, cooking oil, lard, butter, gravy, and food products. Wastewater from food source and food service facilities such as restaurants, processing plants, factories, food courts and hotels are often referred to as "greywater". The terms "greywater", "wastewater" and "effluent" may be used substantially interchangeably herein.

When greywater passes through sewer systems, FOG accumulates inside the pipes, eventually restricting flow with the potential of causing untreated wastewater to back up into businesses and homes, resulting in high clean up and restoration costs and fines. When discharged into septic systems and drain fields, FOG can cause malfunctions, resulting in more frequent tank pump-outs and other expenses. Additionally, manholes can overflow into parks, yards, streets, and storm drains, allowing wastewater to contaminate local waters, including drinking water.

Exposure to untreated wastewater is a public-health hazard. Every year, communities spend significant sums unplugging or replacing grease-blocked pipes, repairing pump stations, and cleaning up costly and illegal wastewater spills. If a blockage can be attributed to a particular business, these communities may charge the business for the repair of the sewer pipes and the spill clean-up. In addition, communities often add a surcharge to wastewater bills if a business exceeds a specified discharge limit. These expenses can be significant.

In response, businesses attempt to reduce their FOG discharge through the use of, e.g., grease traps. However, it is typically not practical to pump grease traps on a continual basis. Even if a grease trap is pumped on a monthly or weekly basis, in that time, significant portions of the grease will break down and turn septic. Not only does the grease have an offensive smell, but it will sink and pass out of the grease trap adding to the BOD (Biochemical Oxygen Demand) and of COD (Chemical Oxygen Demand) at the local sewer plant or contaminate and foul sand mounds or fields of on-lot systems.

The Inventor desires a FOG collector which can be used to collect FOG from effluent.

<CIT> discloses an oil skimming apparatus for removing oil from the surface of a body of water.

<CIT> discloses a device for recovering an oily polluting liquid spread over a water surface, the liquid having a lower specific gravity than and being immiscible with water.

The invention provides a Fats, Oil and Grease (FOG) system as defined in claim <NUM>.

The FOG collector may be configured to be at least partially immersed in the effluent, in use. The floating members may be, or may include, a substantially cylindrical float compartment located in an operatively upper region of the collector.

The FOG collector may be removably insertable into the effluent containing zone. The floating arrangement may be secured to a suspending arrangement by which the collector is operatively suspended in the effluent containing zone. The suspending arrangement may include a plurality of eyelets at a top of the FOG collector.

The heaters may be configured to heat at least a surface layer of the effluent. The heaters may include heating elements depending from the floating members. The heating elements may be electrical heating elements.

The effluent containing zone may be an underground zone. The effluent containing zone may be defined by a pump station, wet well, settlement tank, commercial grease trap or sewage treatment plant.

The collecting arrangement may be configured to suck or pump the FOG and water out of the effluent containing zone, e.g. to an above ground plant. The collecting arrangement may include one or more of a funnel, suction skimmer box, a flexible hose, an inlet pipe, and a pump for removing the effluent from the effluent containing zone.

The collecting arrangement may be configured to be coupled to a FOG treatment, processing and/or separation plant, such that the collecting arrangement operatively sucks or pumps FOG waste to the plant. An outlet of the hose or inlet pipe of the collecting arrangement may operatively be coupled to an inlet of the FOG plant.

The collecting arrangement may include a funnel having an upper lip, wherein the upper lip of the funnel serves as the weir or overflow arrangement and the funnel directs the liquified FOG towards an outlet.

The FOG collector may include at least one mechanical filter. The FOG collector may include a plurality of mechanical filters. The FOG collector may include at least two mechanical filters of different grades comprising a courser filter and a finer filter arranged sequentially. The FOG collector may include a mechanical filter in the form of an outer mesh enclosure around the at least one floating member, the at least one heater, and the collecting arrangement. The FOG collector may include an inner mechanical filter in the form of a mesh or perforated wall around the collecting arrangement.

The FOG collector may include a support arrangement to support the at least one floating member relative to the collecting arrangement. The support arrangement may be in the form of an adjustable bracket, thereby to adjust a spatial relationship of the at least one floating member relative to the collecting arrangement.

The at least one heater may be supported by, and project operatively downwardly from, the at least one floating member.

The FOG treatment system may include a FOG processor in fluid flow communication with the collecting arrangement.

The invention extends to a method of collecting FOG as defined in claim <NUM>.

The collector may further include an effluent returning arrangement. The effluent returning arrangement may include a return pipe configured to discharge treated effluent from the FOG plant back into the effluent containing zone.

The invention will now be further described, by way of example, with reference to the accompanying drawings.

<FIG> illustrate a first embodiment of a FOG collector <NUM> in accordance with the invention. <FIG> illustrate the FOG collector <NUM> in isolation and will be used mainly to describe its structural features, while <FIG> illustrate the FOG collector <NUM> in use and will be used to describe more functional aspects. <FIG> illustrates a second embodiment of the FOG collector <NUM>'. Like features in the embodiments <NUM>, <NUM>' are represented by the same references numerals either not having an apostrophe (e.g., <NUM>) in the first embodiment or having an apostrophe (e.g., <NUM>') in the second embodiment.

The FOG collector <NUM> has at least one floating member <NUM>. In this example, the FOG collector <NUM> has three floating members <NUM> in the form of floats or buoyant elements. Each float <NUM> may be of a light material, e.g., polystyrene and/or of a hollow material, e.g., a sealed plastic enclosure filled with air. The floats <NUM> are less dense than effluent in which they are intended to float and, not only do they float in the effluent, but they support the remainder of the components of the FOG collector <NUM>.

The specific number and configuration of the floats <NUM> may be a design choice. In this example, there are three floats <NUM>, but there could be more or less. Instead of discrete floats <NUM>, there could be larger or connected floats, e.g., one large annular float.

The FOG collector <NUM> has at least one heating arrangement <NUM> configured to warm the effluent, thereby liquifying, at least partially, FOG in the effluent. In this example, the heating arrangement <NUM> comprises three discrete heaters <NUM>, with each heater <NUM> associated with a float. Again, the number and configuration of the heaters <NUM> may be a question of design preference. Each float <NUM> surrounds an associated heater <NUM> (see <FIG>) like an annular sleeve while each heating element <NUM> projects downwardly from the float (see <FIG>) to have direct contact with the effluent, in use. The floats <NUM> and heaters <NUM> are arranged in pairs.

In this configuration, the heaters <NUM> do not need to boil or heat the effluent significantly. The heaters <NUM> are configured to heat or merely warm the effluent to a temperature of about <NUM>-<NUM>. This temperature may vary depending on a specific type or composition of the FOG to be collected but such medium temperatures are usually sufficient to liquify most types of FOG. The heaters <NUM> may include electrical resistive elements powered by electricity to produce the heat.

The FOG collector <NUM> has a collecting arrangement <NUM> configured to draw in at least some of the warmed effluent including the liquified FOG. In this example, the collecting arrangement <NUM> is in the form of a funnel <NUM> (and further referred to as such). The funnel <NUM> has a conical or frustoconical body <NUM> which tapers operatively downwardly. The funnel <NUM> has an upper lip <NUM> at its upper end which serves as a weir or overflow permitting a top layer of the effluent (which is usually predominantly liquified FOG) to flow over the lip <NUM> into the body <NUM> of the funnel <NUM>, the effluent then being channelled by the funnel <NUM> to an outlet.

A mesh wall or sieve <NUM> is provided around the rim <NUM> of the funnel <NUM>. The mesh wall <NUM> is annular and serves as a screen or sieve for effluent overflowing the weir provided by the rim <NUM> (further described below). The mesh wall <NUM> may thus serve as a mechanical filter.

The FOG collector <NUM> has a mesh enclosure <NUM> surrounding and enclosing most of the other components including the floats <NUM>, the heaters <NUM>, and the funnel <NUM>. A shape of the mesh enclosure may be a design choice. In this example, given that there are three float and heater pairs <NUM>, <NUM>, the mesh enclosure <NUM> is a tri-lobed shape to accommodate the other components in a fairly material-efficient manner while providing good surface area and exposure of the funnel <NUM> to surrounding effluent.

A support arrangement in the form of a bracket or frame <NUM> is provided to locate and support the various components relative to each other. Elements of the frame <NUM> radiate outwardly from the funnel <NUM>, to the float/heater pairs <NUM>, <NUM> and to the mesh enclosure <NUM>. The bracket <NUM> may be adjustable, e.g., to adjust a spacing of the float/heater pairs <NUM>, <NUM> relative to the funnel <NUM>. Also, the frame <NUM> may permit dismantling of the FOG collector <NUM> for maintenance, cleaning, repair, etc. or for the interchange of components, e.g., to install a higher capacity heater.

The mesh enclosure <NUM> may have a courser grade than that of the mesh wall <NUM>. Accordingly, the FOG collector <NUM> may provide various grades or levels of screening, thereby to maximise FOG collection and minimise blockage by solids or other detritus. The mesh enclosure <NUM> and/or the mesh wall <NUM> may thus serve as mechanical filters.

The FOG collector <NUM> has an inlet <NUM> (not illustrated in <FIG>, for ease of illustration) which can be used for receiving flushing liquid. This is described in further detail in <FIG>.

<FIG> illustrate the FOG collector <NUM> in use and <FIG> illustrates a FOG system <NUM> incorporating the FOG collector <NUM>. The FOG collector <NUM> is intended to be placed in an effluent containing zone. The effluent containing zone may be a storage cavity of a large storage tank or reservoir <NUM> as illustrated in <FIG>. In an alternate embodiment, the effluent containing zone may be in inner area of a grease trap; in other words, the FOG collector <NUM> may be configured to be placed directly at a site of effluent and FOG generation.

The effluent containing zone contains, in use, general effluent <NUM> including a proportion of FOG <NUM>. The effluent may be generated from domestic or industrial processes. The effluent may be generated by food preparation, waste treatment, etc. Regardless of the source of the effluent, it contains some proportion of FOG <NUM>. The remainder of the effluent may be predominantly water (e.g., grey- or brown water) and may include solid or particulate detritus not being FOG. The FOG <NUM> is generally less dense than water and therefore tends to float in the effluent <NUM>. It is this principle that is leveraged by the present invention. (Although illustrated as a relatively thin layer atop the effluent <NUM>, the FOG <NUM> may in fact comprise a majority of the effluent <NUM>, at least initially. The better the pre-screening of the effluent <NUM>, the more FOG <NUM> will be in the effluent <NUM>.

When the FOG collector <NUM> is placed in the effluent containing zone, it tends to float due to the presence, and action, of the floats <NUM>. The FOG collector <NUM> may be configured to be slightly more than neutrally buoyant, so that it floats in the effluent, but does not project much out of the surface thereof.

Usually, at room temperature, FOG is solid or a highly viscous liquid. It may not have a sufficient degree of flowability to cooperate with a weir. Accordingly, the heaters <NUM> are energised. The FOG collector <NUM> includes an electrical system, illustrated in <FIG> as a plug and cord combination <NUM>, connected to the heaters <NUM>. Accordingly, electrical power is delivered to the heaters <NUM> and they begin to warm up, and to warm the surrounding effluent <NUM>. The electrical system may include a thermostat to control the heaters <NUM> such that the effluent <NUM> is heated to, and then maintained at, <NUM>-<NUM>. As the FOG collector <NUM> is intended to serve, at least partially, an environmentally friendly function, some or all of the electrical input power may be derived from solar panels. Heat waves are illustrated schematically radiating from one of the heaters <NUM> in <FIG>.

As the effluent <NUM> warms up, the FOG <NUM> liquifies. It may still be a relatively viscous fluid compared to water but becomes sufficiently flowable to cooperate with a weir and to flow there-over. The liquified FOG <NUM> may then flow relatively freely through the mesh enclosure <NUM>. Courser particulate detritus is screened out by the mesh enclosure <NUM>, permitting only FOG <NUM> and finer particulate detritus therethrough.

The liquified FOG <NUM> may then flow through the finer mesh wall <NUM>. The mesh wall <NUM> serves to filter out finer particulate detritus to an acceptable degree, so that only FOG <NUM> and tiny particulate detritus can flow over the rim <NUM> of the funnel <NUM>. The buoyancy of the FOG collector <NUM> is configured such that the rim <NUM> of the funnel <NUM> is below a surface of the effluent <NUM>, but above a lower boundary of the FOG <NUM>. In other words, the rim <NUM> is provided in a FOG layer.

This permits the overflow action to draw off the FOG <NUM> only, or at least predominantly, and to leave the remainder of the effluent <NUM> in the effluent containing zone. The overflowed FOG <NUM> (see <FIG>) is then directed downwardly, by gravity, by the conical body <NUM> of the funnel <NUM> and through an outlet in the form of an outlet conduit or pipe <NUM>. The solid arrows in <FIG> also illustrate this process. Additional pumping means could be provided, if desired. The outlet conduit <NUM> may direct the FOG to a FOG processing or treatment apparatus.

Another useful feature of the FOG collector <NUM> is the provision of an in-collector inlet comprising a fluid inlet pipe or conduit <NUM>. "Inlet" in this context is relative to the FOG collector <NUM> as a whole meaning that it is configured to deliver a supply of fluid into the FOG collector <NUM>. The inlet pipe <NUM> may terminate in an arrangement of ducting or nozzles <NUM> provided within the mesh wall <NUM> and directed outwardly towards the mesh wall <NUM>. The inlet pipe <NUM> may deliver a flushing liquid <NUM> towards the mesh wall <NUM> to dislodge or flush any detritus stuck to an outer surface of the mesh wall <NUM>.

Depending on a quantity of flushing liquid <NUM> provided, the flushing liquid <NUM> may also be propelled out of the FOG collector <NUM> through the mesh enclosure <NUM>, thereby also to flush any detritus stuck to an outer surface of the mesh enclosure <NUM>. The flushing liquid <NUM> would then form part of the effluent <NUM>. The flushing liquid <NUM> could be clean water but need not be. The flushing liquid <NUM> should be cleaner than the general effluent <NUM> to be effective, but may be brown or greywater, even wastewater extracted as part of a process upstream or downstream from the FOG collector <NUM>.

The provision of the flushing liquid <NUM> may be periodic. It may be provided cyclically at timed intervals, e.g., every <NUM> minutes or every hour. Instead, it may be provided in response to an event like a degree of blockage of the mesh wall <NUM> or mesh enclosure <NUM> or in response to a flow rate of the overflowed FOG <NUM> dropping below a certain threshold.

The flushing liquid <NUM> may be warm, e.g., a similar temperature to that maintained by the heaters <NUM>. This may assist in warming the effluent <NUM> and reduce power usage by the heaters <NUM>. Some of the flushing liquid <NUM> may inadvertently fall into the funnel <NUM> and be channelled via the outlet conduit <NUM>, but this is acceptable.

<FIG> illustrates the FOG system <NUM> incorporating the FOG collector <NUM>. The reservoir <NUM> has an effluent inlet pipe <NUM> configured to fill the effluent containing zone within the reservoir <NUM> with effluent. Preferably, the effluent <NUM> has been pre-screened to remove large particulate detritus. Accordingly, the FOG system <NUM> may provide three levels of mechanical filtration: (<NUM>) a pre-screening stage for filtering large particulate detritus, (<NUM>) the mesh enclosure <NUM> for filtering medium particulate detritus, and (<NUM>) the mesh wall <NUM> for filtering fine particulate detritus. The effluent inlet pipe <NUM> may be situated in the middle of the reservoir or sump <NUM> or enter in the top above the floating FOG collector <NUM>. It may depend on the level in the reservoir <NUM> when it comes to filling it.

Optionally, but usefully, the effluent may be "pressed" to remove excess water prior to delivery into the reservoir <NUM>. The Applicant is aware of screw systems (e.g., using an Archimedes screw) to press effluent to squeeze out as much water as practicable. Such a system may be employed upstream of the inlet pipe <NUM> to maximise an amount of FOG <NUM> in the effluent <NUM>.

The reservoir <NUM> may include a drainage outlet <NUM> for draining remaining effluent <NUM> from which the FOG <NUM> has been removed. This remaining effluent <NUM> may be predominantly water (e.g., FOG-free greywater). The drainage outlet <NUM> may conduct the remaining effluent <NUM> to wastewater treatment works, to greywater irrigation systems, or to a biofuel plant.

Wastewater which drained from base of an artificial sump or grease trap may consist of bio organic waste particles. When the effluent <NUM> is introduced into the reservoir <NUM>, it will consist of FOG <NUM> and suspended organic solids particles. The FOG <NUM> and these particles may float initially. Once the FOG <NUM> has heated and it and water are drawn through the mesh enclosure <NUM>, to be cycled through the system, it separates from these small organic solids and they then settle to the bottom of the reservoir <NUM>. When the reservoir <NUM> is drained, the organic solids may be separated from the water, using a screen or Archimedes drive. The screened and dewatered organic solids can then be used as feedstock for biogas production or composted.

An advancement to the system <NUM> is to add a cylindrical weir inside the sump <NUM> or use a cylindrical based sump (conical tank); this may channel all of the organic waste particles to the base of the sump <NUM>. The drainage outlet <NUM> may be provided at a bottom of the sump <NUM> and, when opening the drainage outlet <NUM>, the water pressure may "pump" out the settled organic waste first, flushing the system <NUM>. This can be automated by including a solenoid valve in the drainage outlet <NUM>.

The outlet pipe <NUM> may conduct the liquified or drained FOG <NUM> to a FOG processing or treatment apparatus (not illustrated). The inlet pipe <NUM> may provide flushing liquid obtained from the FOG processing or treatment apparatus. Accordingly, although specifics of any connected FOG processing or treatment apparatus are outside the scope of this specification, the FOG collector <NUM> may be configured to be connected to the FOG processing or treatment apparatus in a circular loop such that the FOG collector <NUM> delivers FOG <NUM> to the FOG processing or treatment apparatus and receives flushing liquid <NUM> back therefrom.

Referring now to <FIG>, a second embodiment of the FOG collector <NUM>' is illustrated. Conceptually, this second embodiment is the same as the first, but it is implemented with structural differences. For example, the floats <NUM>' are spaced further away from the collecting arrangement <NUM>'. The floats <NUM>' are mounted on upright support axles <NUM>' and are height-adjustable to configure a height that the collecting arrangement <NUM>' floats relative to a surface level of the effluent <NUM>.

The arms of the frame <NUM>' are more developed and longer. The heaters are not illustrated but operatively would be accommodated within compartments or buckets <NUM>' provided on each arm of the frame <NUM>' just radially inwardly of the floats <NUM>'. The outlet pipe <NUM>' is illustrated more as an output coupler <NUM>' to which an external hose (not illustrated) can be connected.

A more significant structural difference in the second embodiment of the FOG collector <NUM>' is the configuration of the collecting arrangement <NUM>'. While the collecting arrangement <NUM>' is still generally in the form of a funnel, it does not have a mesh wall <NUM> as in the first embodiment of the FOG collector <NUM>. Instead, it has a cover arrangement <NUM>' which comprises a cylindrical skirt and an annular top piece with three spokes. A perforated or mesh rim extension <NUM>' (best seen in <FIG>) is provided concentrically around the funnel body <NUM>' and is coupled to the funnel rim <NUM>'. The cover arrangement <NUM>' is provided on top of the funnel body <NUM>' and rim extension <NUM>' such that the skirt depends downwardly over the funnel body <NUM>'.

Also, in this second embodiment, the inlet pipe <NUM>' is slightly differently configured and can be seen more clearly, particularly in <FIG>. It comprises a central inlet pipe <NUM>' having three nozzles or branches <NUM>' directed radially outwardly. The inlet pipe <NUM>' is accommodated within a matched aperture provided in the cover arrangement <NUM>' and is held securely in place by the cover arrangement <NUM>'. The nozzles <NUM>' are directed outwardly towards the skirt of the cover arrangement <NUM>' which directs the flushing liquid <NUM>' towards the rim extension <NUM>', thereby to flush away detritus.

An aspect which should be emphasised is the medium temperature (in the region of <NUM>-<NUM>, but thus could be increased or decreased moderately depending on the specific composition of the FOG being handled) at which the FOG collector <NUM>, <NUM>' is configured to operate. This makes the FOG collector <NUM>, <NUM>' energy efficient; this is enhanced by the fact that the FOG collector <NUM>, <NUM>' is configured to float (as a floating head) in that the heat delivered by the heaters <NUM> is delivered to a top of the effluent <NUM>.

Accordingly, the Applicant has found in technical trials that the FOG collector <NUM>, <NUM>' does not actually heat the entire volume of the effluent <NUM> but merely the upper levels, or at least more so the upper levels, where the FOG <NUM> is situated, due to the location of the FOG collector <NUM>, <NUM>' and the rising action of heat. Bottom levels of the effluent <NUM> may be cooler, e.g., <NUM>-<NUM> or even room temperature. In other words, there may be a temperature gradient which forms in the effluent <NUM>, increasing from the bottom of the effluent <NUM> to the FOG <NUM> at the top.

This is even further enhanced by the introduction - or re-introduction, if the system <NUM> is configured circuitously - of warmed flushing liquid <NUM>, <NUM>' which may also be in the temperature range of <NUM>-<NUM>.

Claim 1:
A Fats, Oil and Grease (FOG) system (<NUM>) including:
a reservoir (<NUM>) defining an effluent containing zone; and
a FOG collector (<NUM>) provided in the reservoir in the effluent containing zone, the FOG collector including:
a plurality of floating members (<NUM>) which are configured operatively to float in the effluent containing zone;
a plurality of heaters (<NUM>) configured to warm effluent in the effluent containing zone, thereby liquifying, at least partially, FOG in the effluent, wherein the floating members and heaters are arranged in a plurality of groups, each group including at least one of the floating members coupled to at least one of the heaters;
a collecting arrangement (<NUM>) configured to draw in at least some of the warmed effluent including the liquified FOG out of the effluent containing zone for further treatment, processing and/or separation, wherein the collecting arrangement includes a weir or overflow arrangement to draw in the liquified FOG from the effluent containing zone; and
a fluid inlet (<NUM>) configured to direct fluid towards the collecting arrangement, wherein the fluid inlet is configured to receive warm fluid and direct the warm fluid around the collecting arrangement, thereby simultaneously to warm the effluent and liquify the FOG further and to clean or flush the collecting arrangement.