CA2272147C

CA2272147C - Device for separating grease from drain water

Info

Publication number: CA2272147C
Application number: CA 2272147
Authority: CA
Inventors: Michael S. Morrison
Original assignee: MDK Enterprises Inc
Current assignee: MDK Enterprises Inc
Priority date: 1996-11-27
Filing date: 1997-11-24
Publication date: 2005-04-12
Anticipated expiration: 2017-11-24
Also published as: EP0963349A1; US5861098A; EP0963349A4; AU726224B2; EP0963349B1; CA2272147A1; US6345657B1; DE69736128T2; DE69736128D1; AU5513398A; WO1998023537A1

Abstract

An apparatus is provided herein for separating a light liquid (e.g., grease) from a heavy liquid (e.g., water] in a mixture of such liquids. The apparatus is provided with enhanced gravitational separation of such liquids. The apparatus includes a separation chamber for receiving the mixture of liquids, the separation chamber being defined by a plurality of walls and a separation chamber bottom. The separation chamber includes an inlet section, the inlet section comprising an inlet port for introducing th e mixture of liquids into the separation chamber. The apparatus includes a level control for maintaining a pre-selected fluid level of the mixture in the separating chamber. The apparatus includes a discharge section, the discharge section comprising a first exit port for removing the light liquid from the separation chamber, the first exit port being positioned nea r the top of a wall of the chamber. The first exit port comprises a slat. An enclosure, whi ch is connected to the outside of the apparatus, encloses the slot, the enclosure being connected to a second conduit through which the light liquid is discharged. The apparatus includes a downstream section, the downstream section comprising a second exit port in a downstrea m section of the separation chamber for removing the heavy liquid from the separation chamber. The apparatus includes a heater element which is operatively-associated with the separation chamber, the heater element being capable of heating the mixture of liquids which is contained in the separation chamber. The apparatus includes a skimmer which is suspended in the separation chamber by means of a rotatable shaft which is connected t o the separation chamber. The skimmer is configured to direct the light liquid to the first exit port. The skimmer comprises at least one blade which is capable of moving th e mixture of liquids, the skimmer being positioned to rotate in substantially the same plane as the first exit port, the plane being parallel to the fluid level. In a preferred practice of an aspect of this invention, a skimmer and a series of liquid flow obstacles are also employed along the heater element to achieve optimal separation.

Description

(a) TITLE OF THE INVENTION
DEVICE FOR SEPARATING GREASE FROM DRAIN WATER
(b) TECHNICAL FIELD TO WHICH THE INVENTION RELATES
The invention relates to the separation of liquid components having different specific gravities contained in a single feed stream. More particularly, it relates to an apparatus and method for removing fats, oils, greases and the like from wastewater.
(c) BACKGROUND ART
Restaurant kitchens generate wastewater streams containing a number of components aside from water, e.g., oils, greases, and food waste solids. Such wastewater is typically not suitable for transport directly to a sewage plant because of the presence of oils and greases. Specifically, these greasy wastes interfere with the proper operation of the sewage treatment process by, for example, coating the insides of the pipes and tank walls which are used to transport and store the sludge and scum from wastewater. Further, excessive amounts of grease may plug the trickling filters or coat the biological floc which is used in the activated sludge processes of typical wastewater treatment plants. Consequently, many local waste disposal codes require the removal of oils and greases from wastewater prior to transport to the treatment plants.
Oil/grease separators are known which are capable of separating immiscible liquids having different specific gravities. In general, the separators operate by providing sufficient opportunity for gravity to separate the liquids, such that the heavier liquid sinks and the lighter liquid rises. Descriptions of known oil/grease separators follows.
U.S. Patent No. 4,102,787, issued to Geurtsen and was assigned on its face to Machinefabriek Geurtsen Deventer, B.V., and disclosed an apparatus for separating a mixture of liquids of different specific gravities (e.g., oil and water). The Geurtsen apparatus comprised a separation chamber into which a liquid mixture was introduced.
A series of filters was provided below the separation chamber which allowed for the passage of the heavier liquid, to the substantial exclusion of the lighter liquid, the heavier liquid then being collected in a chamber for disposal. The primary inventive feature of the Geurtsen apparatus was a movable-wall portion for controlling the discharge of lighter liquid therefrom. Such apparatus contained essentially no means for enhancing the separation of liquids, but rather depended solely upon gravitational forces to achieve separation.
U.S. Patent No. 5,122,280, issued to Russell et al. and was assigned on its face to Protectaire Systems, Co., and disclosed a method and apparatus for separating oil from oil/water mixtures. This patent included a holding tank that discharged to a separation tank. The outflow to the separation tank was directed underneath a surface underflow weir, after which the lighter liquid rose and was collected. Here again, the separation between the liquids was accomplished primarily on the basis of gravitational forces.
U.S. Patent No. 5,207,895, issued to Basseen et al. and was assigned on its face to Pioneer Air Systems, Inc., and disclosed an oil/water separator that included vertical columns of coalescing media to enhance separation of the two liquid phases.
Movement through the separator was effected by the incoming pressure of the air/oil/water mixture.
While the Basseen et al. apparatus purportedly effectively-removed the majority of oil from a waste stream, the amount of time which was required to pass through columns of solid media was disadvantageous. Moreover, one was faced with the task of rejuvenating the columns after use.
U.S. Patent No. 5,254,267, issued to Deskins et al., disclosed a grease separation system which had a plurality of filters through which the grease-laden liquid mixture had to pass. The filters were situated above a bed of grease-absorbing material, which discharged to a perforated pipe. The separated grease then had to be collected from the grease-absorbing material and from the filters. This method was undesirable, since one had manually to collect and handle grease following the separation process.
U.S. Patent No. 5,340,477, issued to Simon and was assigned on its face to Texaco Inc., and disclosed a separator apparatus for breaking emulsions which were formed between hydrocarbon liquid and an aqueous solution. Essentially, the apparatus included an emulsion tank which received emulsion near its bottom, such that the lighter component rose to the surface where it was collected in a trough that encircled the tank by means of a skimming weir. This apparatus did not employ any means, other than gravitational forces, for achieving the separation of the heavier liquids from the lighter liquids. Thus, this method required an extended period of time for adequate separation.
U.S. Patent No. 5,360,555, issued to Batten and was assigned on its face to Clearline Systems, Inc., and disclosed an oil/grease/water separation apparatus, in which effluent passed through a weir system into a quiescent region. The effluent resided in the quiescent region for a sufficient period of time until the oil/grease floated to the top of the water, where it was collected by a rotating oleophilic disk. Then, the cleaned water passed under a baffle into an outlet chamber. The degree of separation achieved by this apparatus was entirely-dependent upon gravitational forces.
U.S. Patent No. 5,423,986, issued to Valentin and was assigned on its face to Hans Huber GmbH & Co. KG of Berching, Germany, and disclosed an apparatus for the removal of clarified wastewater from circular tanks. The apparatus served to draw-off waste water uniformly, rather than to separate immiscible liquid phases.
U.S. Patent No. 5,445,730, issued to Pattee, disclosed a grease/oil/water separator containing three tanks to achieve separation: a first separation chamber; a trap tank; and a pump tank. The settling chamber separated out debris from the wastewater;
the trap tank separated sludge as well as grease/oil from water by means of gravitational forces encouraged by a diagonal flow path; and the pump tank pumped the grease-separated water through a sand filtering means for further cleaning. The trap tank relied solely upon gravity to achieve the separation of the water from the grease.
The cleaned water was removed by a pipe inlet which was situated near the bottom of the tank. The separator depended entirely upon gravitationally-induced separation of water and grease/oil in the trap tank.
U.S. Patent No. 5,492,619, issued to Batten and was assigned on its face to Clearline Systems, Inc., and disclosed separator system for separating water from grease.
This system included a skimmer for collecting grease, and a detector for detecting the presence of grease in the tank. A heat sink was employed to heat the grease in a grease storage container, but only to prevent solidification of the grease.
Other patents disclosed apparatuses and methods for removing one liquid from contact with another, after separation of the liquids was achieved in a separator.

Examples of such patents included L1.S. Patent Nos. 5,405,538 and 5,451,330.
U.S.
1?atent No. 5,405,538, issued to Batten and was assigned on its face to Clearline Systems, lnc. , and disclosed an apparatus for removing grease from a grease trap separator and transferring the grease to a transfer tank. Thus, the apparatus of U.S. Patent No.

5,405,538 to Batten primarily related to the transport of separated grease, not to the actual separation of grease from a grease-laden wastewater.
U.S. Patent No. 5,451,330, issued to Garrett and was assigned on its face to Advanced Waste Reduction, Inc. , and disclosed a suction skimmer for removing an upper layer of liquid from a vessel. Specifically, the skimmer was contemplated for withdrawing hydrocarbons under substantially-laminar MOW COIldltlC)IIS. The Garrett apparatus itself did not achieve separation of immiscible liquids, but simply removed the lighter liquid upon its separation.
The apparatuses and methods described above relied either solely upon gravitational forces vertically to separate immiscible liquids in a vessel according to their respective densities, or in some instances employed a weir system or a skimmer component to advance separation. None of the above-described apparatuses provided any means to hasten and/or to improve separation beyond that which was naturally-achieved with gravity, other than mechanical means of directing flow, e.g., weir systems and skimmers.
(d) DESCRIPTION OF THE INVENTION
There, thus, remains a need for an apparatus and a method for improving the degree of separation between grease and water contained in wastewater, such that a greater percentage of grease is recovered compared to the above-described apparatuses.
The apparatus and method must be efficient and reliable, and must require only a minimal amount of maintenance.
By a first broad aspect of this invention, an apparatus is provided to separate a light liquid from a heavy liquid in a mixture of these liquids, the light liquid and the heavy liquid being substantially-non-miscible in c>ne another. rfhe apparatus comprises a separation chamber for receiving the mixture, the separation chamber being defined by a plurality of walls and a separation chamber bottom. An inlet section of the separation chamber includes an inlet port for introducing the mixture into the separation chamber. A

level control is provided for maintaining a pre-selected fi7uid level of the mixture in the separating chamber. A discharge section of the separation chamber comprises a first exit port for removing the light liquid from the separation chamber, the first exit port being positioned near the top of a wall of the chamber. The first exit port includes a slot. An enclosure is connected to the outside of the apparatus encloses the slot, the enclosure being connected to a second conduit through which the light liquid is discharged. A
downstream section of the separation chamber comprises a second exit port in a downstream section of the separation chamber for removing the heavy liquid from the separation chamber. A
heater element, which is operatively-associated with the separation chamber, is capable of heating the mixture of liquids which is contained in the separation chamber. A
skimmer, which is suspended in the separation chamber by means of a rotatable shaft which is connected to the separation chamber, serves to direct the light liquid to the first exit port.
The skimmer comprises at least one blade which is capable of moving the mixture of liquids. The skimmer is positioned to rotate in substantially the same plane as the first exit port, that plane being parallel to the fluid level.
By a second broad aspect of this invention, an apparatus is provided to separate grease from water in a mixture of grease and water. The apparatus comprises a separation chamber for receiving the mixture, the separation chamber being defined by a plurality of walls and a separation chamber bottom. An inlet section of the separation chamber includes an inlet port for introducing the mixture of grease and water into the separation chamber. A level control is provided for maintaining a pre-selected liquid level of the mixture in the separation chamber. A discharge section of the separation chamber comprises a first exit port for removing the grease from the separation chamber, the first exit port being positioned near the top of a wall of the chamber. The first exit port comprises a slot. An enclosure which is connected to the outside of the apparatus encloses the slot, the enclosure being connected to a second conduit through which the grease is discharged. A downstream section of the separation chamber includes a second exit port in a downstream section of the separation chamber far removing water from the separation chamber. A heater element, which is operatively-associated with the separation chamber, is capable of heating the mixture of grease and water which is contained in the separation chamber. A skimmer, which is suspended in the separation chamber by means of a rotatable shaft which is connected to the separation chamber, serves to direct grease to the first exit port. The skimmer comprises at least one blade which is capable of moving the mixture of liduids. The skimmer is positioned to rotate in substantially the same plane as the first exit port, that plane being parallel to the fluid level.
By one variant of these two broad aspects of this invention, the separation chamber is defined by four walls, a bottom, and a top.
By a second variant of two broad aspects of this invention, and/or the above variant thereof, at least two of the first, second, and third walls are crne and the same.
By a third variant of two broad aspects of this inventior7, and/or the above variants thereof, the downstream section is separated from the inlet section by at least one fluid flow obstacle, that at least one fluid tlow cybstacle serving further to enhance the separation of the light liquid or grease, and the heavy liquid or water by increasing the amount of time which is spent by the mixture of liquids in the separation chamber.
By a first variation thereof, the at least one fluid flow obstacle includes a baffle and a false bottom of the separation chamber. The baffle is substantially-parallel to a wall of the separation chamber containing the inlet section, and the false bottom is substantially-parallel to the bottom of the separation chamber. 'fhe baftle has a bottom above the separation chamber bottom and a top above the fluid Level. The false bottom is positioned between the baffle and the wall of the separation chamber containing the inlet section and has four edges, of which three edges are adjoined to two other walls of the separation chamber and to the bottom of the baffle, with a fourth edge of the false bottom being positioned near, hut not touching, the wall containing the inlet section. This thereby defines a passageway for heavy liquid between the wall containing the inlet section and the fourth edge of the false bottom, such that the mixture of liquids must flow underneath the false bottom to reach the downstream section ftom the inlet section.
By a second variation thereof, the at least one tluid flow obstacle further comprises a weir extending upwardly from the bottom of the separation chamber to an adjustable elevation, the weir being positioned substantially-parallel to the baffle between the baffle and the second exit port.
By a fourth variant of these two broad aspects of this invention, and/or the above variants thereof, the inlet section further comprises a first conduit, the first conduit having a first end and a second end, the first end being connected to the inlet port, and the second end being configured to discharge the mixture of liquids into the internals of the separation chamber. By a first variation thereof, the conduit is curved such that the second end is configured to discharge the mixture of liquids toward the wall containing the inlet section.
By a second variation thereof, the conduit is curved such that the second end is configured to discharge the mixture of liquids towards the first wall.
By a variant of these two broad aspects of this invention, and/or the above variants thereof, the at least one blade of the skimmer is sufficiently long such that it extends through the slot, thereby being configured to push the light liquid through the slot and toward the second conduit.
By a fifth variant of these two broad aspects of this invention, and/or the above variants thereof, the apparatus further comprises an outlet trap on a wall of the separation chamber containing the second exit port, such that the heavy liquids are urged to pass through the outlet trap before discharge through the second exit port, the outlet trap being configured to limit return of the heavy liquids into the separation chamber.
By a sixth variant of these two broad aspects of this invention, and/or the above variants thereof, the apparatus further comprises an agitating blade which is suspended near the bottom of the separation chamber inside the separation chamber on a rotatable shaft which is connected to the separation chamber, the agitating blade being configured to agitate the mixture of liquids such that the mixture of liquids is urged to flow in an upward direction in the separation chamber By a third broad aspect of this invention, an apparatus is provided to separate a light liquid from a heavy liquid in a mixture of these liquids, the light liquid and the heavy liquid being substantially~non-miscible in «ne another. 'hhe apparatus comprises a separation chamber for receiving the mixture of liquids, the separation chamber being defined by four walls, a bottom, and a top. An inlet section of the separation chamber comprises an inlet port which is defined by a tirst wall of the separation chamber for introducing the mixture into the separation chamber, the inlet section further comprising a first conduit having a first end and a second end, the first end being connected to the inlet port and the second end being configured to discharge the mixture of liquids inside the sf;paration chamber. A discharge section of the separation chamber comprises a first exit port which is defined as a slot by a second wall of the separation chamber, the first exit port being positioned near the top of the second wall, wherein the first exit port is enclosed on the outside of the apparatus by an enclosure, the enclosure being connected to a second conduit through which the light liquid is urged to be discharged from the separation chamber. A downstream section of the separation chamber, comprises a second exit port which is defined by a third wall of the separation chamber for removal of the heavy liquid from the separation chamber, the downstream section also comprising an outlet trap which is connected to the third wall of the separation chamber to prevent the heavy liquids from returning to the separation chamber once reaching the second exit port. A
heater element, which is operatively-associated with the separation chamber, is capable of heating the mixture of liquids which is contained in the separation chamber. A skimmer, which is suspended in the separation chamber by means of a rotatable shaft which is connected to t:be separation chamber, is configured to direct the light liquid to the first exit port. The skimmer comprises at least one blade which is configured to move the mixture of liquids.
The skimmer is positioned to rotate in substantially the same plane as the first exit port, that plane being substantially-parallel to the fluid level. An agitating blade, which is suspended near the bottom of the separation chamber ic~:~ide the separation chamber on the rotatable shaft, is configured to agitate the mixture of liquids such that the mixture of liquids is used to flow in an upward direction in the separation chamber. A
level control is provided for controlling the liquid level in the separation chamber. A
plurality of liquid flow obstacles is provided which are configured to separate the downstream section from the inlet section. That plurality of liquid flow obstacles includes a baffle, a weir, and a false bottom of the separation charrtber.
By a fourth broad aspect of this invention, an apparatus is provided to separate a light liquid from a heavy liquid in a mixture of these liquids, the light liquid and the heavy liquid being substantially-non-miscible in one another. 'The apparatus comprises a separation chamber for receiving the mixture of liquids, the separation chamber being defined by four walls, a bottom, and a top ~ An inlet section of the separation chamber comprises an inlet port which is defined by a first wall of the separation chamber for introducing the mixture into the separation chamber, the inlet section further comprising a first conduit having a first end and a second end, the first end being connected to the inlet port and the second end being configured to discharge the mixture of liquids inside the separation chamber. A discharge section of the separation chamber comprises a first exit port which is defined as a slat by a second wall of the separation chamber, the first exit port being positioned near the tap of the sc;cond wall, the first exit port being enclosed on the outside of the apparatus by an enclosure, that enclosure being connected to a second conduit through which the light liquid is discharged from the separation chamber. A
downstream section of the separation chamber comprises a second exit port which is defined by a third wall of the separation chamber for removal of the heavy liquid from the separation chamber, the downstream section also comprising an outlet trap which is connected to the third wall of the separation chamber and which is configured to prevent the heavy liquids from returning to the separation chamber once reaching the second exit port. A heater element, which is operatively-associated with the separation chamber, is capable of heating the mixture of liquids which is contained in the separation chamber. A
skimmer, which is suspended in the separation chamber by means of a rotatable shaft vcrhich is connected to the separation chamber, is configured to direct the light liquid to the first exit port. The skimmer comprises at least one blade which is configured to move the mixture of liquids. The skimmer is positic:med to rotate in substantially the same plane as the first exit port, that plane being substantially-parallel to the t7uid level. An agitating blade, which is suspended near the bottom of the separation chamber inside the separation chamber on the rotatable shaft, is capable c>f agitating the mixture of liquids such that the mixture of liquids is urged to flow in an upward direction in the separation chamber. A
level control is provided for controlling the liquid level in the separation chamber. A
plurality of liquid flow obstacles is provided which is configured to separate the downstream section from the inlet section. The plurality of liquid flow obstacles includes a baffle, a weir, and a false bottom of the separation chamber. 'The baffle is substantially-parallel to the first wall and has a bottom above the separation chamber bottom and a top above the liquid level. The weir extends upwardly from the bottom of the separation chamber to an adjustable elevation and is positioned substantially-parallel to the baffle between the baffle and the second exit port. The false bottom is substantially-parallel to the bottom. The false bottom is positioned between the baffh; and the first wall, and has four edges, of which three edges are respectively adjoined to the second wall of the separation chamber, a fourth wall of the separation chamber and the bottom of the baffle, with a fourth edge of the false bottom being positioned near, but not touching, the first wall, thereby defining a passageway for the heavy liquid between the first wall and the f°ourth edge of the false bottom, such that the mixture is urged to flow underneath the false bottom to reach the downstream section from the inlet section. By a first variation thereof, the liquid is grease, and the heavy liquid is water.
By a fifth broad aspect of this invention, a method is provided for separating a light liquid from a heavy liquid in a mixture of these liquids, the light liquid and the heavy liquid being substantially-non-miscible in one another. 'hhe method includes the step of providing a separation chamber for holding the mixture, and defining the separation chamber by a plurality of walls and a separation chamber bottom. 'The next step involves providing an inlet port in an inlet section c>f the separation chamber, defining the inlet port by a first wall of the separation chamber, ~~nd flowing the mixture into the separation chamber via the inlet port. The next step involves controlling the amount of the mixture which is introduced into the separation chamber such that a pre-selected fluid level is maintained within the separation chamber. The next step involves enhancing separation of the substantially-non-miscible liquids by increasing the specific gravity differential therebetween, and by decreasing the viscosity of the light liquid, by the step of heating the mixture in the separation chamber. 'Che next step involves providing a discharge section with a first exit port, defining the first exit port by a second wall of the separation chamber for removing of the light liquid from the separation chamber, positioning the first exit port near the top of the second wall, enclosing the slot by an enclosure which is connected to the outside of the apparatus, providing a second conduit through which the light liquid is discharged, and collecting the light liquid which is floating on top of the heavy liquid in a discharge section of the separation chamber. 'The next step involves collecting the heavy liquid in a downstream section of the separation chamber', the downstream section including a second exit port in a downstream section of the separation chamber, and defining the second exit port by a third wall of the separation chamber for removing the heavy liquid from the separation chamber. Immediately prior to step e, skimming the light liquid floating on top of the heavy liquid in the separation chamber using a skimmer which is suspended in the separation chamber by means of a rotating shaft which is connected to said separation chamber, the skimmer comprising at least one blade and which, in operation, is caused to rotate in substantially the same plane as the first exit port, the plane being parallel to the fluid level, thereby directing the light liquid to said first exit port for collection in step e.
By a sixth broad aspect of this invention, a method is provided for separating a light liquid from a heavy liquid in a mixture of these liquids, the light liquid and the heavy liquid being substantially-non-miscible in one another. The method includes the step of providing a separation chamber for holding the mixture, and defining the separation chamber by a plurality of walls and a separation chamber bottom. The next step involves providing an inlet port in an inlet section cof the separation chamber, and flowing the mixture into the separation chamber via an inlet port. The next step involves controlling the amount of the mixture which is introduced into the separation chamber such that a pre-selected fluid level is maintained within the separation chamber. The next step involves enhancing separation of the substantially-non-miscible liquids by increasing the specific gravity differential therebetween, and by decreasing the viscosity of the light liquid by the step of heating the mixture in the separation chamber. The next step involves providing a discharge section including a first exit port. for removing the light liquid from the separation chamber, providing the first exit port near the top of a wall, providing the first exit port as a slot, and providing an enclosure which is connected to the outside of the apparatus to enclose the slot, connecting the enclosure to a second conduit through which the light liquid is discharged, and collecting the light liquid which is floating on top of the heavy liquid in a discharge section of the separation chamber. The next step involves providing a downstream section including a second exit port in a downstream section of the separation chamber for removing the heavy liquid from the separation chamber, and collecting the heavy liquid in a downstream section of the separation chamber.
The next step involves suspending a skimmer in the separation chamber, providing the skimmer with a rotatable shaft which is connected to the separation chamber, providing the skimmer with ax least one blade, positioning the blade to rotate on the c~otatable shaft in substantially the same plane as the first exit port, the plane being parallel to the t7uid level, and immediately prior to the light liquid collecting step, skimming the light liquid which is floating on top of the heavy liquid in the separation chamber, by means of rotation of the blade of the ~?
skimmer, thereby directing the light liquid to the first exit port for collection in the light liquid collection step.
By one variant of these fifth and sixth broad aspects of this invention, the method heating step is provided by a heater element which is contained within the separation chamber, thereby heating the separation chamber using the heater.
By a second variant of these fifth and sixth broad aspects of this invention, and/or the above variant thereof, the method comprises the additional step of separating light liquid or grease from heavy liquid or water.
By a third variant of these fifth and sixth broad aspects of this invention, and/or the above variants thereof, the method comprises the step of defining the separation chamber by four walls, a bottom, and a top.
By a fourth variant of these fifth and sixth broad aspects of this invention, and/or the above variants thereof, the method further comprises the further step of separating the downstream section from the inlet section by providing at least one liquid flow obstacle, thereby increasing the amount of time the heavy liquid resides in the separation chamber prior to prior collections.
By a first variation thereof, the method comprises the steps of providing the at least one fluid flow obstacle as a baffle and a false bottom of the separation chamber, providing the baffle in an orientation which is substantially-parallel to the wall of the separation chamber containing the inlet section. The method comprises the next step of providing the false bottom in an orientation which is substantially-parallel to the bottom of the separation chamber. The method comprises the next step of providing a bottom of the baffle above the separation chamber bottom, providing a top of the baffle above the liquid level. The rx~ethod comprises the next step of positioning the false bottom between the baffle and the wall of the separation chamber containing the inlet section. The method comprises the next step of providing the false bottom with four edges, of which three edges are adjoined to two other walls of the separation chamber to the bottom of the baffle. The method comprises the final step of positioning a fourth edge of the false bottom near, but not touching, the wall containing the inet section, thereby defining a passageway for the heavy liquid between the wall containing the inlet section and the fourth edge of the false bottom, l) and causing the heavy liquid to flow underneath the false bottom to reach the downstream section from the inlet section.
By a second variation thereof, the method comprises the additional step of providing at least one liquid flow obstacle with a weir extending upwardly from the bottom of the separation chamber to an adjustable elevation, and positioning the weir substantially-parallel to the baffle between the baffle and the second exit port.
By a fifth variant of these fifth and sixth broad aspects of this invention, and/or the above variants thereof, the method comprises the steps of prcwiding a first conduit with a first end and, with a second end, connecting the first end to the inlet port, flowing the mixture into the separation chamber by means of a first conduit, and discharging the mixture of liquids into the internals of the separation chamber by way of the second end.
By a first variation thereof, the method comprises the steps of providing the conduit as a curved conduit, and discharging the mixture of liquids from the second end toward the first wall. By a second variation thereof, the method comprises the steps of providing the conduit as a curved conduit, and discharging the mixture of liquids from the second end toward the wall containing the inlet section.
By a sixth variant of these fifth and sixth broad aspects of this invention, and/or the above variants thereof, the method comprises the step ot~ providing the blade of the slimmer as a significantly long blade, and then pushing the light liquid through the slot and toward the second conduit by extending the at least one sufficiently long blade of the slimmer through the slot.
By a seventh variant of these fifth and sixth broad aspects of this invention, and/or the above variants thereof, the method comprises the further step of providing an outlet trap which is connected to the interior of tine separation chamber on the third wall, thereby preventing the heavy liquid from returning to the separation chamber once reaching the second exit port.
By an eighth variant of these fifth and sixth broad aspects of this invention, and/or the above variants thereof, the method comprises the further step of providing an outlet tt~ap which is connected to the interior of the separation chamber on a wall containing the second exit port, thereby preventing the heavy liquid from returning to the separation chamber once reaching the second exit port. By a first variation thereof, the method comprises the step of providing at least two of the first, second, and third walls as one and t:he same wall.
By a ninth variant of these fifth and sixth broad aspects of this invention, and/or the above variants thereof, the method comprises the further steps of suspending an agitating blade near the bottom of the separation chamber, agitating the mixture in the separation chamber by means of the agitating blade which is secured to a rotating shaft which is provided within the separation chamber, and directing flow c>f the mixture upwardly in the separation chamber by means of the blade. This thereby further increases the time the heavy liquid resides in the separation chamber.
Accordingly, aspects of the present invention generally provide an apparatus and a method for separating a light liquid from a heavy liquid in a mixture of these liquids which enhance the gravitational separation of such liquids by heating the mixture.
Specifically, the apparatus includes a separation chamber far receiving the liquid mixture, with the separation chamber being defined by a plurality of walls and a bottom. An inlet section of the separation chamber includes an inlet port which is defined by a first wall of the separation chamber for introducing the liquid mixture into the separation chamber. A level control is provided for maintaining a pre-selected fluid level of the liquid mixture in the separation chamber. A discharge section of the separation chamber includes a first exit port which is defined by a second wall of the separation chamber for removing the light liquid from the separation chamber, the first exit port being positioned near the top of the second wall. A downstream section of the separation chamber includes a second exit port which is defined by a third wall of the separation chamber for remaviu~g the heavy liquid from the separation chamber. A heater element is associated with the separation chamber, the heater element being capable of heating the mixture which is contained in the separation chamber.
The heater element serves to heat the entire liquid mixture residing in the separation chamber. By heating the mixture, the separation of the light and heavy liquids is believed to be enhanced in two ways. Firstly, the viscosity of the light liquid is decreased so that it more readily migrates to the surface of the mixture, and is mane easily discharged through the first exit port. Secondly, heating the mixture will typically decrease the density of the light liquid more than it decreases the density of the heavy liquid, such that physical separation by gravity is made more effective by increasing the density differential.

l5 It is contemplated that various aspects of the present apparatus and method will be employed, among other uses, for separating fats, oils, grease, and other high molecular-weight fatty acids from water, e.g., wastewater which is drained from restaurant sinks. An aspect of the present method is sufficiently effective in that the water so-cleaned may be directly discharged to conventional sewers in an environmentally-safe manner, and in compliance with typical local waste disposal codes.
The oil and grease which is removed from the wastewater is held in a convenient storage vessel for ultimate disposal.
In addition to improved efficiency in separating oil and grease from wastewater, the apparatus of aspects of the present invention advantageously requires minimal maintenance and handling during operation. Thus, aspects of the apparatus and method of the present invention offer improved efficiency without sacrificing the simplicity of a gravity-based separation system.
The present apparatus and the present method, in their various aspects, are useful for the improved separation of a liquid having a lighter specific gravity from a second liquid having a higher specific gravity. Herein, the term "liquid" is used in its normal sense to encompass non-solid materials and includes relatively-viscous materials, e.g., oils of various types, dissolved or suspended greases, and the like. It is specifically contemplated that various aspects of the invention will be useful in achieving the separation of grease from water with regard to wastewater issuing from commercial kitchen sinks. However, it will be apparent to those skilled in the art that various aspects of the apparatus and method described herein are equally applicable to separating other types of mixtures of light liquids and heavy liquids besides oil and water, e.g., a mixture of two mutually-immiscible organic chemicals having sufficiently different specific gravities.
The basic premise of the method of a broad aspect of the present invention is the enhancement of gravitational separation by heating the mixture and, optionally and preferably, providing skimming and increasing residence time in the settling tank. The gravitational separation of immiscible liquids of different densities is known, and has been capitalized upon, in the prior art apparatuses described above.
Essentially, when two immiscible liquids of different densities are present in a holding tank or separation chamber, the lighter liquid "floats" on top of the heavier, denser, liquid.
Accordingly, when a mixture of grease and water has sufficient residence time in a tank, the grease, as the lighter liquid, will form a layer on top of the water. Such has been the premise of many apparatuses in the prior art. As used herein, the term "grease"
encompasses oil and other lighter-than-water liquids.
Here, the improved apparatus incorporates a heater element into the settling chamber to enhance the separation achieved by gravity alone. Without subscribing to any particular theory, it is believed that, by heating the mixture of liquids, one effects two desirable consequences in the separation thereof: (1) the viscosity of the light liquid is decreased, better enabling it to migrate to the surface where it can be removed; and (2) the density of grease is decreased to a greater extent than is the density of water, thereby enhancing the differential in densities to the benefit of gravitational separation.
Regardless of the correctness of these theories, the separation which is achieved by apparatus of aspects of the present invention is superior to that in the prior art.
In addition to the heater component, the apparatus of aspects of the present invention, preferably employs a skimmer component and fluid flow obstacles to improve separation, with the latter increasing residency time in the settling tank.
(e) DESCRIPTION OF THE FIGURES
In the accompanying drawings, FIG. 1 is a schematic perspective view of an embodiment of an aspect of an apparatus within the scope of the invention, illustrating various embodiments thereof;
FIG. lA is an elevational view of the bottom blade in cross-section, taken across the line A'-A' as indicated in FIGS. 1 and 2;
FIG. 2 is a top plan schematic view of the fluid flow for the apparatus of FIG.
1;
FIG. 3 is a front elevational schematic view of the fluid flow apparatus of the preceding figures;
FIG. 4 is a front elevational view of the apparatus of the preceding figures as it is contemplated for commercial installation in a restaurant kitchen; and FIGS. 5 and 6 are schematic side elevational and top plan views, respectively, of a prior art grease trap which is described in the Example below.

(f) AT LEAST ONE MODE FOR CARRYING OUT THE INVENTION
Referring now to the drawings, in which like numbers represent like parts throughout the several views, FIG. 1 is a perspective view of a separator apparatus 10 for separating grease from water. The separation chamber 12 of this embodiment of an aspect of this invention contains the mixture of at least two liquids (e. g. , grease and water), providing the residence time for the grease to rise to the top of the mixture for collection. While the separation chamber 12 of this embodiment of an aspect of this invention as illustrated in the Figures has a generally-rectangular form, other configurations may be employed.
The mixture of liquids is introduced into the separation chamber 12 by means of an inlet port 14. Once the mixture of liquids is introduced into the separation chamber 12, the heavier liquid sinks to the bottom of the mixture of liquids while the lighter fluid migrates to the surface of the mixture of liquids, all by the natural force of gravity. The separation of the lighter liquid from the heavier liquid is enhanced by heating the mixture of liquids during its residence time in the separation chamber 12. The mixture of liquids is heated using a heater element 16, which is contemplated to be an immersion water heater within the separation chamber 12. The heater element 16 is connected to an electric heater 17. An example of a suitable commercially-available immersion heater is the heater which is known by the trade-mark CHROMALOXTM Type CJ Automatic Water Heater. It is contemplated that, in the case of separating grease from water, the temperature of the mixture is, optimally, kept above 92°F
(33°C), typically at 110°F
(43°C). However, for maximum efficiency, the heater settings should be changed for different installation grease consistencies.
The lighter liquid that collects at the surface of the mixture of liquids in the separation chamber 12 is collected via a discharge port 18. The discharge port 18 is positioned such that it coincides with the top of the liquid level of the mixture of liquids in the separation chamber 12. Preferably, the discharge port 18 is in the shape of a slot, and an enclosure 20 is provided for the discharge port 18 on the outside of the separator apparatus 10. The enclosure 20 directs the collected light liquid to a discharge conduit 22, through which the light liquid flows for disposal.

The heavy liquid that sinks to the bottom of the separator chamber 12 is allowed to flow out of the separation chamber 12 through a heavy liquid, e.g., water, outlet port 24. The separation which is achieved in the practice of aspects of the present invention is sufficient such that the heavy liquid, e.g., water, that was formerly laden with grease, may be discharged directly to sewage lines upon emerging from the separator apparatus 10.
In one embodiment of an aspect of the present invention, a skimmer 26 is employed to sweep, in the direction of the discharge port 18, the top layer of grease or light liquid, that migrates to the top of the mixture of liquids. The skimmer 26 is contemplated to be in the form of a slow-moving, rotating blade (or blades, two co-linear ones being preferred) that rotates in the top portion of the liquid level of the mixture of liquids in the separation chamber 12. The length of the blades is, preferably, pre-selected such that their tips actually protrude through the discharge port 18, which is preferably a slot, as described above.
It would be desirable to introduce the mixture of liquids into the separation chamber 12 in such a way that creates additional turbulence in the liquid flow patter which is established by the skimmer 26, as opposed to introducing a mixture of liquids, such that it is swept along with the skimmed grease directly toward the discharge port 18 before having time to separate. Therefore, it is preferable to provide an inlet conduit 30 to introduce the mixture of liquids at an optimal point within the internals of the separation chamber 12. In order to produce turbulence, assuming a counter-clockwise rotation of the skimmer 26, the inlet conduit 30 would be curved as depicted in FIG. 2, with the discharge end/inlet conduit discharge 32 of the conduit 30 positioned to release incoming mixture of liquids against the direction of the liquid flow path which is created by the skimmer 26. FIG. 3 illustrates the preferred elevational position of the discharge end/inlet conduit discharge 32 in relation to the skimmer 26.
It is contemplated that the skimmer 26 will be connected to a central shaft 28 that will rotate the skimmer 26. The central shaft 28 is powered by a motor and fan assembly (not shown) which is contained in housing 35, as shown in FIG. 3. An example of a suitable motor that is commercially-available is that known by the trade-mark MAXI-TORQUETM Gearmotor, of Dayton, although the motor is not so limited.
A second bottom blade or blades 34 is, preferably, attached to the central shaft 28 to rotate at the bottom of the mixture of liquids, with the speed of rotation 5 contemplated to be 3rpm to l2rpm. The second bottom blade or blades 34 serves to stir up any solids that may have settled near the bottom of the mixture of liquids, so that such solids are retained in the heavy liquid, and, thus, similarly-discharged through the heavy liquid, e.g., water outlet port 24. Therefore, the second bottom blade or blades 34 will have been bevelled as illustrated in FIG. lA to achieve turbulence and upward liquid 10 flow in the mixture of liquids.
With further regard to solids, a strainer (not shown) is, preferably, employed to filter relatively large solid particles out of the mixture of liquids before it is introduced into the separator apparatus 10. In an embodiment of an aspect of the present invention, the strainer would be installed in front of the inlet port 14, with the strainer having a 15 metal mesh design with 1/8-inch perforations.
The separator apparatus 10 is designed such that a constant liquid level is maintained, such that the skimmer 26 continuously sweeps the top layer of the mixture of liquids toward the discharge port 18. A flow control fixture 36 is employed to try to maintain a constant liquid level by adjusting the opening of the inlet port 14 to meet the 20 discharge requirements of the drainage system to which the separator apparatus 10 is connected. Essentially, the flow control fixture 36 consists of a valve 37 in the inlet conduit 30 either to open, or to close, depending on whether more mixture of liquids is required to maintain a pre-selected fluid level in line with the position of the skimmer 26 and the discharge port 18. The liquid level control system employed in the practice of an aspect of the present invention is not limited to any particular type. A
pump (not shown) operated in conjunction with the valve 37, when open, to pump water into the separation chamber 12 may be used, if necessary, or the apparatus may be connected directly to the discharge of a drainage system. A liquid-level switch, not shown in the Figures, may be used to turn-off the pump (and the electric heater 17) when the level of the liquid in the separation chamber 12 is below a predetermined height.

In order further to improve the liquid separation which is achieved in the practice of aspects of the present invention, the separation chamber 12 is provided with a tortuous flow path for the heavy liquid to follow before being discharged through the heavy liquid, e. g. , water outlet port 24. Specifically, a series of liquid flow obstacles is provided in an embodiment of an aspect of the present invention, to increase the residence time of the mixture of liquids in the separation chamber 12 to allow more complete separation of the liquids.
In one preferred embodiment of the present invention which is illustrated in FIG.
3, the liquid flow obstacles which are employed include a false bottom 40, a baffle 42, and a weir 44, which preferably is adjustable although the specific design, or the combination, of the liquid flow obstacles is not so limited. The flow characteristics of the mixture of liquids in the practice of an aspect of the present invention are illustrated in FIG. 4 by the dashed arrows.
In one embodiment of an aspect of the present invention, the baffle 42 spans the entire width of the separation chamber 12 and extends from the false bottom 40 to above the liquid level. The false bottom 40 is, preferably, positioned to meet the baffle 42 at a 90° angle, thereby preventing the flow of the mixture of liquids directly from the inlet port 14 or discharge end/inlet conduit discharge 32 to the heavy liquid, e. g.
, water outlet port 24. Rather, the false bottom 40 defines an opening 46 between the edge of the false bottom 40 and the wall containing the inlet port 14 that leads to a passageway 48 beneath the false bottom 40 for the heavy liquid, e.g., water.
Once the heavy liquid, e.g., water, advances through the passageway 48, the heavy liquid, e. g. , water, must span the weir 44 before reaching the heavy liquid, e. g. , water outlet port 24. The weir 44, is adjusted in accordance with the liquid level in the separation chamber 12. In an embodiment of an aspect of the present invention, the heavy liquid, e. g. , water, which successfully-spans the weir 44 is then discharged through the heavy liquid, e.g., water outlet port 24. An outlet trap 50 is provided at the heavy liquid, e.g., water outlet port 24 to prevent the heavy liquid, e.g., water, from back-flowing into the separation chamber 12. Thus, the heavy liquid, e. g. , water, is able to leave the separation chamber 12 only after flowing laterally through the false bottom 40, then upwardly past the baffle 42, then downwardly past the weir 44, and finally through an outlet trap 50 in order to reach the heavy liquid, e. g. , water outlet port 24.
The heavy liquid, e.g., water, so-discharged after separation, in the separator apparatus 10, are sufficiently-clean enough to be disposed into the sewer lines.
The separator apparatus 10, of an aspect of the present invention, is contemplated to clean 24 to 36 gallons per minute of wastewater from a commercial kitchen environment. It is noted that, in order to achieve optimal separation capabilities, the separation chamber 12 must be sized appropriately. In a preferred embodiment, the separation chamber 12 is made of 304 STAINLESS STEEL,.M and is sized to hold 9 gallons of liquid, and the water outlet port 24 is 4 inches below the discharge port 18 (at skimmer level) .
The separator apparatus 10 is contemplated to be used in commercial kitchens to remove grease and oils from sink wastewater. FIG. 4 illustrates how the separator apparatus 10 may be installed in a commercial kitchen setting. Specifically, a pipe 52 is run from the kitchen sink 54 to the inlet port 14, thereby delivering grey water containing grease and oils to the separator apparatus 10 for cleaning prior to disposal into the sewer lines. The grease and oils are collected in a grease container 56, which may be conveniently emptied and the contents disposed of in accordance with local hazardous waste disposal regulations. Alternatively, the grease container 56 may be a sealable drum that is itself disposable in accordance with local hazardous waste disposal regulations.
At any rate, the separator apparatus 10 of an aspect of the present invention does not require workers manually to collect grease from filters, nor does it require extensive maintenance. Rather, it is contemplated that the separator apparatus 10 of an aspect of the present invention requires only routine flushing with clean water.
The benefits achieved in the practice of aspects of this invention are illustrated in the Example below.
EXAMPLE
A comparison was made between the effectiveness of a prior art grease trap and the apparatus of an aspect of the present invention in cleaning grease-laden water from a working restaurant kitchen sink delivered at a rate of 32 gallons per minute. The wastewater from the kitchen sink, later connected to the grease trap and the present apparatus, had an untreated oil and grease concentration of 2,500 mg/L to 3,000 mg/L, which was measured gravimetrically. When necessary, the grease content was controlled by adding grease previously-separated from the same source.
A schematic view of the elevational view and top plan view of the prior art grease trap 70 are presented as FIGS. 5 and 6, respectively. Essentially, the prior art grease trap employed in this example consisted of a series of baffles 72 in which grease was collected as the wastewater flowed through the trap. It is noted that, in the operation of such a grease trap 70, the grease must be periodically and routinely collected from the grease trap by hand; if the grease is allowed to build-up in such a grease trap, it is thereafter unable effectively to remove grease from wastewater.
To illustrate the effectiveness of the apparatus of an aspect of the present invention in removing grease from kitchen wastewater, a conventional grease trap 70 (40-lb capacity) and the apparatus of an aspect of the present invention were alternatively connected to the same kitchen sink (not shown) in a working restaurant.
Specifically, the apparatus of an aspect of the present invention as depicted in FIG. 1 was connected to the kitchen sink in a similar fashion to that depicted in FIG. 4. As measured gravimetrically, the following results were obtained:
Table 1~ Comparison of the Effectiveness of a Grease Trap and the Annaratus of an Aspect of the Present Invention in Removing Oil and Grease Restaurant Wastewater.
Apparatus mg/L, before mg/L, after treatment treatment Prior Art Grease Trap 2,650 620 Apparatus of an Aspect of the Present Invention 2, 650 15 Therefore, it has been demonstrated that an apparatus within the scope of aspects of the present invention is much more effective in removing oils and greases from wastewater than a prior art grease trap. Further, the apparatus of an aspect of the present invention is superior to the prior art grease trap in convenience, since it does not require manual scooping of collected grease.
As understood by one skilled in the art, the material which is trapped from water drains consists of various grades of grease that are utilized according to their quality and toxicity. In decreasing order of usefulness, the top grade is used in the manufacture of soaps and perfumes, followed by pet-food additives, and lubricants. The lowest-grade grease is discarded because it is considered too toxic for any commercial use.
Inasmuch as grease, which is trapped in conventional grease traps, deteriorates as it builds-up prior to its removal, the apparatus of an aspect of the present invention also provides a means for improving the quality of the material separated from drain water because of its continuous operation. In general, the grease which is obtained from the operation of the apparatus of an aspect of the present invention is all top grade and is suitable for the most productive applications.
Thus, there has been disclosed herein various aspects of an apparatus and a method for separating and removing oils, greases, and the like, from water.

Claims

1. An apparatus to separate a light liquid from a heavy liquid in a mixture of said liquids, said light liquid and said heavy liquid being substantially-non-miscible in one another, said apparatus comprising:
a) a separation chamber for receiving said mixture of liquids, said separation chamber being defined by a plurality of walls and a separation chamber bottom;
b) an inlet section of said separation chamber, said inlet section comprising an inlet port for introducing said mixture of liquids into said separation chamber;
c) a level control for maintaining a pre-selected fluid level of said mixture in said separating chamber;
d) a discharge section of said separation chamber, said discharge section comprising a first exit port for removing said light liquid from said separation chamber, said first exit port being positioned near the top of a wall of the chamber, said first exit port comprising a slot, and wherein an enclosure which is connected to the outside of said apparatus encloses said slot, said enclosure being connected to a second conduit through which said light liquid is discharged;
e) a downstream section of said separation chamber, said downstream section comprising a second exit port in a downstream section of said separation chamber for removing said heavy liquid from said separation chamber;
f) a heater element which is operatively-associated with said separation chamber, said heater element being capable of heating said mixture of liquids which is contained in said separation chamber; and g) a skimmer which is suspended in said separation chamber by means of a rotatable shaft which is connected to said separation chamber, said skimmer serving to direct said light liquid to said first exit port, said skimmer comprising at least one blade which is capable of moving said mixture of liquids, said skimmer being positioned to rotate in substantially the same plane as said first exit port, said plane being parallel to said fluid level.

2. An apparatus to separate grease from water in a mixture of grease and water, said apparatus comprising:

a) a separation chamber for receiving said mixture of grease and water, said separation chamber being defined by a plurality of walls and a separation chamber bottom;
b) an inlet section of said separation chamber, said inlet section comprising an inlet port for introducing said mixture of grease and water into said separation chamber;
c) a level control for maintaining a pre-selected liquid level of said mixture of grease and water in said separation chamber;
d) a discharge section of said separation chamber, said discharge section comprising a first exit port for removing said grease from said separation chamber, said first exit port being positioned near the top of a wall of the chamber, said first exit port comprising a slot, and wherein an enclosure which is connected to the outside of said apparatus encloses said slot, said enclosure being connected to a second conduit through which said grease is discharged;
e) a downstream section of said separation chamber, said downstream section comprising a second exit port in a downstream section of said separation chamber for removing water from said separation chamber;
f) a heater element which is operatively-associated with said separation chamber, said heater element being capable of heating said mixture of grease and water which is contained in said separation chamber; and g) a skimmer which is suspended in said separation chamber by means of a rotatable shaft which is connected to said separation chamber, said skimmer serving to direct grease to said first exit port, said skimmer comprising at least one blade which is capable of moving said mixture of liquids, said skimmer being positioned to rotate in substantially the same plane as said first exit port, said plane being substantially-parallel to said liquid level.

3. The apparatus of claim for claim 2, wherein said separation chamber is defined by four walls, a bottom, and a top.

4. The apparatus of claim 1, claim 2 or claim 3, wherein at least two of said first, second, and third walls are one and the same.

5. The apparatus of any one of claims 1 to 5, wherein said downstream section is separated from said inlet section by at least one liquid flow obstacle, said at least one liquid flow obstacle serving further to enhance the separation of said light liquid or grease and said heavy liquid or water by increasing the amount of time which is spent by said mixture of liquids in said separation chamber.

6. The apparatus of claim 5, wherein said at least one liquid flow obstacle comprises a baffle and a false bottom of said separation chamber, said baffle being substantially-parallel to a wall of said separation chamber containing said inlet section, and said false bottom being substantially-parallel to said bottom of said separation chamber, said baffle having a bottom above said bottom of said separation chamber and a top above said liquid level, said false bottom being positioned between said baffle and said wall of said separation chamber containing said inlet section and having four edges, of which three edges are adjoined to two other walls of said separation chamber and to said bottom of said baffle, with a fourth edge of said false bottom being positioned near, but not touching, said wall containing said inlet section, thereby defining a passageway for said heavy liquid between said wall containing said inlet section and said fourth edge of said false bottom, such that said mixture of liquids must flow underneath said false bottom to reach said downstream section from said inlet section.

7. The apparatus of claim 6, wherein said at least one liquid flow obstacle further comprises a weir extending upwardly from said bottom of said separation chamber to an adjustable elevation, said weir being positioned substantially-parallel to said baffle between said baffle and said second exit port.

8. The apparatus of any one of claims 1 to 7, wherein said inlet section further comprises a first conduit, said first conduit having a first end and a second end, said first end being connected to said inlet port, and said second end being configured to discharge said mixture of liquids into the internals of said separation chamber.

9. The apparatus of claim 8, wherein said conduit is curved, such that said second end is configured to discharge said mixture of liquids toward said wall containing the inlet section.

10. The apparatus of claim 8, wherein said conduit is curved, such that said second end is configured to discharge said mixture of liquids toward said first wall.

11. The apparatus of any one of claims 1 to 10, wherein said at least one blade of said skimmer is sufficiently long such that it extends through said slot, thereby being configured to push said light liquid through said slot and toward said second conduit.

12. The apparatus of any one of claims 1 to 11, wherein said apparatus further comprises an outlet trap on a wall of said separation chamber containing the second exit port, such that said heavy liquid is urged to pass through said outlet trap before discharge through said second exit port, said outlet trap being configured to limit return of said heavy liquid into said separation chamber.

13. The apparatus of any one of claims 1 to 12, wherein said apparatus further comprises an agitating blade which is suspended near said bottom of said separation chamber inside said separation chamber on a rotatable shaft which is connected to said separation chamber, said agitating blade being configured to agitate said mixture of liquids such that said mixture of liquids is urged to flow in an upward direction in said separation chamber.

14. An apparatus to separate a light liquid from a heavy liquid in a mixture of said liquids, said light liquid and said heavy liquid being substantially-non-miscible in one another, said apparatus comprising:
a. a separation chamber for receiving said mixture of liquids, said separation chamber being defined by four walls, a bottom, and a tap;
b. an inlet section of said separation chamber, said inlet section comprising an inlet port which is defined by a first wall of said separation chamber for introducing said mixture of liquids into said separation chamber, said inlet section further comprising a first conduit having a first end and a second end, said first end being connected to said inlet port and said second end being configured to discharge said mixture of liquids inside said separation chamber;
c. a discharge section of said separation chamber, said discharge section comprising a first exit port which is defined as a slot by a second wall of said separation chamber, said first exit port being positioned near the top of said second wall, wherein said first exit port is enclosed on the outside of said apparatus by an enclosure, said enclosure being connected to a second conduit through which said light liquid is urged to be discharged from said separation chamber;
d. a downstream section of said separation chamber, said downstream section comprising a second exit port which is defined by a third wall of said separation chamber for removal of said heavy liquid from said separation chamber, said downstream section also comprising an outlet trap which is connected to said third wall of said separation chamber and which is configured to prevent said heavy liquid from returning to said separation chamber once reaching said second exit port:
e. a heater element, which is operatively-associated with said separation chamber, said heater element being capable of heating said mixture of liquids which is contained in said separation chamber;
f. a skimmer which is suspended in said separation chamber by means of a rotatable shaft which is connected to said separation chamber, said skimmer being configured to direct light liquid to said first exit port, said skimmer comprising at least one blade which is configured to move said mixture of liquids, said skimmer being positioned to rotate in substantially the same plane as said first exit port, said plane being substantially-parallel to said fluid level;
g. an agitating blade which is suspended near said bottom of said separation chamber inside said separation chamber on said rotatable shaft, said agitating blade being configured to agitate said mixture of liquids such that said mixture of liquids is urged to flow in an upward direction in said separation chamber;
h. a level control for controlling the liquid level in said separation chamber; and i. a plurality of liquid flow obstacles which are configured to separate said downstream section from said inlet section, said plurality of liquid flow obstacles comprising a baffle, a weir, and a false bottom of said separation chamber.

15. An apparatus to separate a light liquid from a heavy liquid in a mixture of said liquids, said light liquid and said heavy liquid being substantially-non-miscible in one another, said apparatus comprising:
a. a separation chamber for receiving said mixture of liquids, said separation chamber being defined by four walls, a bottom, and a top;
b. an inlet section of said separation chamber, said inlet section comprising an inlet port which is defined by a first wall of said separation chamber for introducing said mixture of liquids into said separation chamber, said inlet section further comprising a first conduit having a first end and a second end, said first end being connected to said inlet port and said second end being configured to discharge said mixture of liquids inside said separation chamber;
c. a discharge section of said separation chamber, said discharge section comprising a first exit port which is defined as a slot by a second wall of said separation chamber, said first exit port being positioned near the top of said second wall, wherein said first exit port is enclosed on the outside of said apparatus by an enclosure, said enclosure being connected to a second conduit through which said light liquid is discharged from said separation chamber;
d. a downstream section of said separation chamber, said downstream section comprising a second exit port which is defined by a third wall of said separation chamber for removal of said heavy liquid from said separation chamber, said downstream section also comprising an outlet trap which is connected to said third wall of said separation chamber and which is configured to prevent said heavy liquid from returning to said separation chamber once reaching said second exit port;
e. a heater element which is operatively-associated with said separation chamber, said heater element being capable of heating said mixture of liquids which is contained in said separation chamber;

f. a skimmer which is suspended in said separation chamber by means of a rotatable shaft which is connected to said separation chamber, said skimmer being configured to direct light liquid to said first exit port, said skimmer comprising at least one blade which is configured to move said mixture of liquids, said skimmer being positioned to rotate in substantially the same plane as said first exit port, said plane being substantially-parallel to said fluid level;
g. an agitating blade which is suspended near said bottom of said separation chamber inside said separation chamber on said rotatable shaft, said agitating blade being configured to agitate said mixture of liquids such that said mixture of liquids is urged to flow in an upward direction in said separation chamber;
h. a level control for controlling the liquid level in said separation chamber; and i. a plurality of liquid flaw obstacles which is configured to separate said downstream section from said inlet section, said plurality of liquid flow obstacles comprising a baffle, a weir, and a false bottom of said separation chamber;
wherein said baffle is substantially-parallel to said first wail and has a bottom above said separation chamber bottom and a top above said liquid level;
said weir extends upwardly from said bottom of said separation chamber to an adjustable elevation and is positioned substantially-parallel to said baffle between said baffle and said second exit port; and said false bottom is substantially-parallel to said bottom, said false bottom being positioned between said baffle and said first wall, and has four edges, of which three edges are respectively adjoined to said second wall of said separation chamber, a fourth wall of said separation chamber and said bottom of said baffle, with a fourth edge of said false bottom being positioned near, but not touching, said first wall, thereby defining a passageway for said heavy liquid between said first wall and said fourth edge of said false bottom, such that said mixture of liquids is urged to flow underneath said false bottom to reach said downstream section from said inlet section.

16. The apparatus of claim 14 or claim 15 wherein said light liquid is grease, and wherein said heavy liquid is water.

17. A method for separating a light liquid from a heavy liquid in a mixture of said liquids, said light liquid and said heavy liquid being substantially-non-miscible in one another, said method comprising the steps of:
a. providing a separation chamber for holding said mixture of liquids, and defining said separation chamber by a plurality of walls and a separation chamber bottom;
b. providing an inlet port in an inlet section of said separation chamber, defining said inlet port by a first wall of said separation chamber, and flowing said mixture of liquids into said separation chamber via said inlet port;
c. controlling the amount of said mixture of liquids which is introduced into said separation chamber such that a pre-selected liquid level is maintained within said separation chamber;
d. enhancing separation of said substantially-non-miscible liquids by increasing the specific gravity differential therebetween, and by decreasing the viscosity of said light liquid, by the step of heating said mixture of liquids in said separation chamber;
e. providing a discharge section with a first exit part, defining said first exit port by a second wall of said separation chamber for removing of said light liquid from said separation chamber, positioning said first exit part near the top of said second wall enclosing said slot by an enclosure which is connected to the outside of said apparatus, providing a second conduit through which said light liquid is discharged, and collecting said light liquid which is floating on top of said heavy liquid in said discharge section of said separation chamber;
f. providing said downstream section with a second exit port in a downstream section of said separation chamber, defining said second exit port by a third wall of said separation chamber for removing said heavy liquid from said separation chamber, and collecting said heavy liquid in a downstream section of said separation chamber; and g. immediately prior to step e, skimming said light liquid floating on top of said heavy liquid in said separation chamber using a skimmer which is suspended in said separation chamber by means of a rotating shaft which is connected to said separation chamber, said skimmer comprising at least one blade and which, in operation, is caused to rotate in substantially the same plane as said first exit port, said plane being parallel to said fluid level, thereby directing said light liquid to said first exit part for collection in step e.

18. A method for separating a light liquid from a heavy liquid in a mixture of said liquids, said light liquid and said heavy liquid being substantially-non-miscible in one another, said method comprising the steps of:
a. providing a separation chamber for holding said mixture of liquids, and defining said separation chamber by a plurality of walls and a separation chamber bottom;
b. providing an inlet port in an inlet section of said separation chamber, and flowing said mixture into said separation chamber via said inlet port;
c. controlling the amount of said mixture of liquids which is introduced into said separation chamber such that a pre-selected liquid level is maintained within said separation chamber;
d. enhancing separation of said substantially-non-miscible liquids by increasing the specific gravity differential therebetween, and by decreasing the viscosity of said light liquid, by the step of heating said mixture of liquids in said separation chamber;
e. providing a discharge section comprising a first exit port for removing said light liquid from said separation chamber, providing said first exit port near the top of a wall, collecting said light liquid floating on top of said heavy liquid in said discharge section of said separation chamber, providing said first exit port as a slot, providing an enclosure which is connected to the outside of said apparatus to enclose said slot, and connecting said enclosure to a second conduit through which said light liquid is discharged;
f. providing a downstream section comprising a second exit port in a downstream section of said separation chamber for removing said heavy liquid from said separation chamber, and collecting said heavy liquid in a downstream section of said separation chamber; and g. suspending a skimmer in said separation chamber, providing said skimmer with a rotatable shaft which is connected to said separation chamber, providing said skimmer with at least one blade, positioning said blade on said rotatable shaft in substantially the same plane as said first exit port, said plane being substantially-parallel to said liquid level, and immediately prior to step e, skimming said light liquid which is floating on top of said heavy liquid in said separation chamber by means of rotation of said blade of said skimmer, thereby directing said light liquid to said first exit port for collection in step e.

19. The method of claim 17 or claim 18, comprising the steps of providing a heater element contained within said separation chamber, and beating said separation chamber using said heater.

20. The method of any one of claims 17 to 19, comprising the additional step of separating said light liquid or grease from said heavy liquid or water.

21. The method of any one of claims 17 to 20, comprising the further step of defining said separation chamber by four walls, a bottom, and a top.

22. The method of any one of claims 17 to 21, comprising the further step of separating said downstream section from said inlet section by providing at least one liquid flow obstacle, thereby increasing the amount of time said heavy liquid resides in said separation chamber prior to collection in step f.

23. The method of claim 22, comprising the steps of:
providing said at least one liquid flow obstacle as a baffle and a false bottom of said separation chamber;
providing said baffle in an orientation which is substantially-parallel to said wall of said separation chamber containing said inlet section;
providing said false bottom in an orientation which is substantially-parallel to said bottom of said separation chamber;
providing a bottom of said baffle above said separation chamber bottom;
providing a top of said baffle above said liquid level;
positioning said false bottom between said baffle and said wall of said separation chamber containing the inlet section;
providing said false bottom with four edges, of which three edges, are adjoined to two other walls of said separation chamber to said bottom of said baffle;
positioning a fourth edge of said false bottom near, but not touching, said wall containing said inlet section, thereby defining a passageway for said heavy liquid between said wall containing the inlet section and said fourth edge of said false bottom; and causing said heavy liquid to flow underneath said false bottom to reach said downstream section from said inlet section.

24. The method of claim 23, comprising the additional steps of:
providing said at least one liquid flow obstacle with a weir extending upwardly from said bottom of said separation chamber to an adjustable elevation; and positioning said weir substantially-parallel to said baffle between said baffle and said second exit port.

25. The method of claim 23, comprising the additional steps of:
providing a first conduit with a first end and a second end;
connecting said first end to said inlet port;
flowing said mixture into said separation chamber by means of said first conduit; and discharging said mixture of liquids into the internals of said separation chamber by way of said second end.

26. The method of claim 25, comprising the additional steps of:
providing said conduit as a curved conduit; and discharging said mixture of liquids from said second end toward said first wall.

27. The method of claim 26, comprising the additional steps of:
providing said conduit as a curved conduit; and discharging said mixture of liquids from said second end toward said wall containing the inlet section.

28. The method of any one of claims 17 to 27, comprising the step of providing said blade of said skimmer as a significantly long blade and then pushing said light liquid through said slot and toward said second conduit by extending said at least one sufficiently long blade of said skimmer through said slot.

29. The method of any one of claims 17 to 28, comprising the further step of providing an outlet trap which is connected to the interior of said separation chamber on said third wall, thereby preventing said heavy liquid from returning to said separation chamber once reaching said second exit port.

30. The method of any one of claims 17 to 28 comprising the further step of providing an outlet trap which is connected to the interior of said separation chamber on a wall containing said second exit port, thereby preventing said heavy liquid from returning to said separation chamber once reaching said second exit port.

31. The method of any one of claims 17 to 30, comprising the step of providing at least two of said first, second, and third walls as one and the same wall.

32. The method of any one of claims 17 to 31, comprising the further steps of:
suspending an agitating blade near said bottom of said separation chamber;
agitating said mixture in said separation chamber by means of said agitating blade which is connected to a rotating shaft which is provided within said separation chamber;
and directing flow of said mixture upwardly in said separation chamber by means of said agitating blade, thereby further increasing the time said heavy liquid resides in said separation chamber.