[0001] This application claims priority benefits to United States Provisional Application No. 61/344,587, the contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION

[0002] In one of its aspects, the present invention relates to a transfer apparatus and system for transfer or contacting of a chemical species between a higher density fluid and a lower density fluid. In another of its aspects, the present invention relates to an improved process for the transfer or contacting of a chemical species between a higher density fluid and a lower density fluid using the transfer apparatus and system described herein.

DESCRIPTION OF THE PRIOR ART

[0003] Many processes require a gas/liquid system that includes a large surface area in order to facilitate a reaction or physical-chemical process, referred to generally herein as "transfer". The transfer of a chemical species between two fluids may be necessary for a number of applications; for example, transfer may be carried out for the purpose of removing a gas from a liquid (stripping), removing a gas from a combined gas flow in order to purify the flow (separation, absorption or scrubbing), or transferring a gas chemical species to a liquid in order to promote a chemical reaction. In another application, a gas or liquid containing one or more chemical species may be passed over a catalyst in order to promote a chemical reaction.

[0004] A number of devices and arrangements to facilitate the desired contact between a gas and a surface of a liquid are known. Such devices include, for example, packed columns, spray columns, and cross flow contactors. In known devices, high specific surface area per unit of volume (A/V ) ratios are generally desired, but are limited by physical constraints. One such constraint is the nature of the media; whereas smaller media produces higher A/V ratios, reducing media size increases the risk of plugging and the associated liquid hold up, and gas flow head loss increase.

[0005] One gas/liquid process that requires a large transfer surface area is ammonia stripping or absorbing (scrubbing). Existing ammonia stripping devices encounter efficiency and operational problems at ambient temperatures when the pH of the ammonia bearing liquid falls below about 10. Consequently, excess base is added in order to maintain stripping efficiencies and, on completion of stripping, it is generally required that the pH be adjusted downward by adding an acid prior to discharging the water. Alternatives to raising the pH such as elevating the temperature of the ammonia bearing water, and or reduce the pressure of the atmosphere above the water surface have been explored, but encounter problems at commercial scale.

[0006] Water containing high ammonia concentrations is often wastewater that evolves from digested organic wastes, or urine. This ammonia is often at high concentration(500mg N/L - 5000 mg N/L). Removing the ammonia by biological processes (nitrification and denitrification) is problematic due to the limitations inherent in the microbes that facilitate this process. Consequentially large tanks, and considerable electrical power is required.

[0007] Removing the ammonia by stripping and adsorbing has been attempted on many occasions and has been reported to be problematic when employing conventional mass transfer technology. Problems of plugging, scale accumulation, and excessive electrical power consumption have been reported, and it is generally held that these solutions are not economically viable.

[0008] There is a need in the art for an apparatus for ammonia stripping that allows the liquid to be stripped to lower concentrations than existing devices and with a final pH between 7 and 9, with overall energy consumption less than required for biological removal, and without the requirement for, and expense of, addition of chemicals for pH adjustment and/or readjustment of the liquid. [0009] There is a need in the art for an apparatus for ammonia stripping and adsorption that is not highly susceptible to accumulation of solids, scale and process failure due to excessive power requirements, scale accumulation, or plugging.

SUMMARY OF THE INVENTION

[0010] It is an object of the present invention to obviate or mitigate at least one of the above- mentioned disadvantages of the prior art.

[0011] It is an object of the present invention to provide a novel transfer apparatus for facilitating transfer between a higher density fluid and a lower density fluid.

[0012] Other objects of the present invention will be apparent to those of skill in the art having in hand the present specification.

[0013] In one of its aspects, the present invention provides a transfer apparatus for facilitating transfer between a higher density fluid and a lower density fluid, the apparatus comprising: a transfer chamber having a higher density fluid zone for receiving the higher density fluid and a lower density fluid zone for receiving the lower density fluid, wherein the higher density fluid zone and the lower density fluid zone are adjacent each other; a contactor mounted in the transfer chamber, at least a portion of which is moveable between the higher density fluid zone and the lower density fluid zone to allow for controlled exposure of the surface of the contactor to the higher density fluid; a current generator connected to the transfer chamber for generating a first current in the lower density fluid zone; a fluid control mechanism for generating a second current in the higher density fluid zone.

[0014] In another aspect, the transfer apparatus further comprises at least one fluid distribution device to allow for controlled distribution of the higher density fluid onto the exposed surface of the contactor.

[0015] In another of its aspects, the present invention provides a transfer system for facilitating transfer between a higher density fluid and a lower density fluid, the system comprising: a plurality of apparatus in fluid communication with one another, each apparatus comprising: a transfer chamber having a higher density fluid zone for receiving the higher density fluid and a lower density fluid zone for receiving the lower density fluid; the higher density fluid zone having a higher density fluid inlet and a higher density fluid outlet and the lower density fluid zone having a lower density fluid inlet and a lower density fluid outlet; a contactor mounted in the transfer chamber, at least a portion of which is moveable within the lower density fluid zone; at least one fluid distribution device fluidly connected to the higher density flulid zone and operable to transfer the higher density fluid from the higher density fluid zone to the at least one contactor; and a current generator connected to the transfer chamber for generating a current in the lower density fluid zone.

[0016] In yet another of its aspects, the present invention provides the use of the present transfer system to strip and/or strip and recover a chemical species, such as ammonia, from a wastewater stream.

[0017] In yet another of its aspects, the present invention provides the use of a transfer system of the invention to ozonate a wastewater stream.

[0018] In yet another of its aspects, the present invention provides a reactor comprising: a chamber for receiving a fluid to be reacted; and a moveable contactor mounted within the chamber and coated with a catalyst for catalysing the reaction of the fluid.

[0019] In a further aspect, the present invention provides a transfer apparatus for facilitating transfer between a higher density fluid located in a high density fluid zone and a lower density fluid located in a low density fluid zone, the apparatus comprising: a contactor, at least a portion of which is moveable between the higher density fluid zone and the lower density fluid zone to allow for controlled exposure of the surface of the contactor to the higher density fluid; and a current generator for generating a first current in the low density fluid zone; and a fluid control mechanism for generating a second current in the higher density fluid zone.

[0020] In yet another aspect, the present invention provides a transfer apparatus for facilitating transfer between a higher density fluid and a lower density fluid, the apparatus comprising: a transfer chamber having a higher density fluid zone for receiving the higher density fluid and a lower density fluid zone for receiving the lower density fluid, wherein the higher density fluid zone and the lower density fluid zone are adjacent each other; a contactor rotatably mounted in the transfer chamber, at least a portion of which is moveable between the higher density fluid zone and the lower density fluid zone to allow for controlled exposure of the surface of the contactor to the higher density fluid, the contactor comprising a central core portion operable to allow for the passage of fluid therethrough and including a sheet of inert material wrapped around the outer surface thereof to form a spiral, the inert material being at least partially penetrable by at least one of the lower density fluid and the higher density fluid; a fan connected to the transfer chamber for generating a first current in the lower density fluid zone; and a motor for generating a second current in the higher density fluid zone.

[0021] In another aspect, the present invention provides a process for the transfer of a chemical species between a higher density fluid and a lower density fluid comprising the steps of (i) providing a higher density fluid and a lower density fluid; (ii) providing a contactor at least a portion of which is moveable between the higher and lower density fluids and at least a portion of which is partially penetrable by at least one of the higher and lower density fluid; (iii) generating a first current in the lower density fluid; (iv) generating a second current in the higher density fluid, the second current being in the opposite direction to the first current; and (v) moving the contactor between the higher and lower density fluids such that exposure of the contactor to the higher density fluid is controlled.

[0022] In another aspect, the present invention provides a process for the transfer of a chemical species between a higher density fluid and a lower density fluid comprising the steps of (i) providing a higher density fluid and a lower density fluid; (ii) providing a contactor at least a portion of which is moveable between the higher and lower density fluids and at least a portion of which is partially penetrable by at least one of the higher and lower density fluid; (iii) generating a first current in the lower density fluid; (iv) generating a second current in the higher density fluid, the second current being in the opposite direction to the first current; (v) moving the contactor between the higher and lower density fluids such that exposure of the contactor to the higher density fluid is controlled; (vi) spraying the exposed surface of the contactor with a pre-determined amount of additional higher density fluid for a pre-determined amount of time. [0023] In yet another aspect, the present invention provides a transfer apparatus for facilitating transfer between a higher density fluid and a lower density fluid, the apparatus comprising: a transfer chamber having a higher density fluid zone for receiving the higher density fluid and a lower density fluid zone for receiving the lower density fluid, wherein the higher density fluid zone and the lower density fluid zone are adjacent each other; a series of contactors rotatably mounted in the transfer chamber, at least a portion of the surface of each contactor being moveable between the higher density fluid zone and the lower density fluid zone, and at least partially penetrable by at least one of the lower density fluid and the higher density fluid to allow for controlled exposure of the surface of the contactor to the higher density fluid; a fan connected to the transfer chamber for generating a first current in the lower density fluid zone; and a means for generating a second current in the higher density fluid zone.

[0024] The present inventor has conceived of a transfer apparatus for facilitating transfer of a chemical species between a higher density fluid and a lower density fluid. The apparatus comprises rotating or partially rotatable media (contactor) that is subject to the application of a flow of higher density fluid applied in a manner so as to cover the surface of the rotating contactor. This is preferably achieved by means of a flow distribution device comprising at least one pipe or tube located more or less radially to the rotation axis of the media, and containing one or more holes accompanied by a deflector located such that the higher density fluid forms a fan shaped flow, or spray, that impinges on, and penetrates the rotating contactor. A gas flowing across the contactor contacts the whetted contactor surface permitting transfer of a chemical species between the gas and the liquid, or the liquid and the gas. The contactor may consist of conventional random or structured packing mounted in suitable restraining containers, or specialized structured packing such as 3XR's SpiraFlow™ media. The orientation of the device and rotation axis of the contactor may be vertical, horizontal, or some intermediate angle. In most applications a plurality of contactors will be employed in a series arrangement on a common rotating axis.

[0025] The present transfer apparatus is particularly well suited for use in applications where there is the possibility of accumulation of foreign materials on or in the contactor. In order to periodically dislodge and remove the foreign material the contactors are separated by several centimetres, and a device to conduct a high velocity jet of high density fluid is installed between the contactors. The device is moveable so that the high velocity jet may travel in a radial direction so as to cover all of the rotating contactor surfaces. Where convenient the high velocity jet may flow in two directions so as to apply a cleaning flow to adjacent rotating contactors at a single pass. Depending on the application, the high velocity jet comprising the high density fluid may be composed of any combination of: the high density fluid flowing through the contactor, clean water, a chemical species that promotes the release of the accumulated foreign material. Depending on the application, the high velocity jet may be applied contemporaneously with the continued operation of the device, or the flow of the high density fluid and/or the low density fluid may cease during the high velocity jet application. Depending on the application, the high velocity jet may be a continuous flow or may be pulsating or structured to be of varying configurations as required to achieve an effective cleaning.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Embodiments of the present invention will be described with reference to the accompanying drawings, wherein like reference numerals denote like parts, and in which:

Figure 1 illustrates a cross sectional side view of one embodiment of the present transfer apparatus taken along the length of the transfer apparatus;

Figure 2 illustrates a cross sectional view of the embodiment of Figure 1 ;

Figure 3 illustrates a cross section of a device similar to Figure 1, except that the central pipe serves only a structural purpose and the low density fluid flows in a duct within the perimeter cavities (in all other significant respects the operation of the device shown in Figure 3 is the same as that of Figure 2); and

Figure 4 illustrates a cross section of a device similar to Figure 1, except that it is arranged in a vertical rather than a horizontal orientation and rotates about a vertical axis.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0027] While the system of the present invention is suitable for reacting a higher density fluid with a lower density fluid, most typically it will be used to react a liquid with a gas and, consequently, the preferred embodiments of the invention will be described in these terms for clarity purposes.

[0028] The general operation and use of the system described herein is as described in International Publication Number WO2007/030924 (Haggerty et. al.) with the following modifications to the mechanism of exposure of the contactor, to the fluid within the transfer apparatus, described below. In addition, the transfer apparatus described herein includes at least one pump and fluid distribution device to allow for the controlled exposure of the contactor to the fluid, as described further below. Whereas Haggerty et. al. describes a situation where the media is partially immersed in the liquid, this need not be the case with the device described herein. Partial immersion of the contactor is optional. In general the preferred configuration is that the media not be immersed. The non-immersed application will be described.

[0029] There is provided an improved transfer apparatus, system and method that allows for controlled exposure of the contactor to a higher density fluid. There is provided an improved transfer apparatus, system and method that is configured differently than the arrangements described in Haggerty et. al.. Additionally there is provided a means of dislodging and removing foreign materials that may accumulate on and in the contactor or contactors.

[0030] With reference to Figure 1, there is shown an apparatus 110 of the present invention. Generally, apparatus 110 comprises a transfer chamber 112 containing a higher density fluid zone 114 coupled to a high density fluid distribution device 120, and a lower density fluid zone 116 positioned within and between the contactors. In use, higher density fluid zone 114 will contain or receive a higher density fluid to be treated, while lower density fluid zone 116 will contain or receive a lower density fluid to be treated. In the context of the present application, "treated" will be understood to mean having been passed through the operating transfer apparatus or system such as to allow the desired transfer (e.g., of chemical species) to have occurred. One or more moveable (e.g., rotating) contactors 118 is housed in transfer chamber 1 12, and at least a portion of rotating contactor 1 18 is rotatable across the lower density fluid zone 1 16. As can be seen, in the embodiment illustrated, the transfer chamber includes a series of spaced contactors 118. In the embodiment shown, the contactors 118 form an 8 compartment stripping section 130 at one end of the transfer chamber and a 3 compartment scrubbing section 150 at the other end. In a preferred embodiment, the contactor 118 comprises a spiral sheet that is wound about a central core transfer pipe 162, as described in Haggerty et. al., referred to above.

[0031] The central core is operable to rotate and is driven by rotation drive 170. The central core may consist of a pipe that serves the dual purpose of a torsional/structural media support and a gas transfer duct 160, as shown in Figure 1 and 2. Alternatively, the central core may be separated from the low density fluid transfer duct 160 and may be a smaller shaft 164 that only serves a torsional/structural function, as is shown in Figure 3. In the arrangement shown in Figure 3 the low density fluid (gas) transfer duct 162 may be positioned externally relative to the transfer chamber 112, or it may be incorporated into one or more corners of the apparatus 110. There may be more than one low density fluid transfer duct 162, e.g. there may be two ducts, each located in a corner of the apparatus 110. A current generator or fan 160, shown in Figure 1, is connected to transfer chamber 112 to generate a first current (shown by arrows in Figure 1) in lower density fluid zone 116. While fan 160 is shown inside the transfer chamber 1 12, as will be evident to a person skilled in the art, it could be positioned outside the transfer chamber 112.

[0032] Figure 2 is a cross sectional view of one embodiment of the transfer chamber 112, viewed from the side of the transfer chamber 112 showing a contactor 118 and two fluid distribution devices 120.

[0033] Located between each contactor 118 is at least one fluid distribution device 120, also referred to herein as a media loading header and nozzles 120, which will be described in further detail below. The fluid distribution device 120 is connected to a media loading pump 121 which is configured to feed high density fluid from the high density fluid zone 1 14 into the pump 121 and subsequently into the fluid distribution device 120.

[0034] The depth of the higher density liquid is preferably maintained at a level in the collector below the contactor 118, at a level that enables feeding of the high density liquid into the media loading pump 121 to allow for controlled distribution of the high density liquid onto the contactor while also allowing for exposure of the surface of the contactor 118 to the circulating gas. The surface of the rotating contactor 118 is continuously whetted using the fluid distribution device 120.

[0035] As can be seen in Figures 1 and 2, the fluid distribution device 120 is positioned between adjacent contactors 118 and is positioned so that the nozzles, identified at numeral 123 are directed onto a surface of at least one of the contactors that the fluid distribution device 120 is positioned next to. The radial orientation shown in figure 2 is for illustrative purposes. The positioning, angle and number of fluid distribution devices will vary depending on the nature of the fluid being directed. It will be understood that the fluid distribution device 120 is operable to be configured to distribute high density liquid on one surface of one contactor or may be positioned to distribute high density liquid on the surface of both adjacent contactors, i.e. in two directions. As can be seen in Figure 2, in the illustrated embodiment there are two fluid distribution devices located between adjacent contactors, however, it will be understood that only one may be used or more than two may be used depending on the characteristics of the high density fluid, the size of the nozzles 123 and the capacity of the fluid distribution device 120 to distribute liquid onto the contactor surface relative to the amount of liquid required to be loaded on the contactor surface, and the rotational rate of the contactor.

[0036] The fluid distribution device 120 is supplied by a header 125. As can be seen in the Figures, the header 125 is external to the transfer chamber. However, different configurations may be employed whereby a portion or all of the header is located within the transfer device and allow for wetting by the nozzles 123 of the contactor surface. The number of jets or nozzles whetting the contactor is determined by the volume and flow pattern of the nozzles. In general it is desired to apply a flow to the contactor that is varied along the radius such that there is a more or less equal specific quantity of flow applied to the contactor surface across the radial distribution of the contactor.

[0037] The number of flow distribution devices will vary depending on the characteristics of the fluid being applied. For example when stripping ammonia at 40°C, a single distribution device was shown to be as effective as two distribution devices, whereas at 50°C, two distribution devices produced improved performance from that with a single device. The improvement described herein provides for more efficient wetting of the contactor surface, and the availability of the full cross section of the contactor surface to gas flow and mass transfer activity, which increases the capacity of the transfer apparatus. The ability to control the wetting of the contactor surface through the controlled distribution of higher density fluid, using the fluid distribution device(s) allows for more efficient distribution of the higher density fluid which also allows for more efficient mass transfer activity on the surface of the contactor. This improvement is further enhanced by the configuration in Figure 3 in which most of the cross section previously occupied by the transfer pipe 162 is made available for mass transfer. The low density fluid transfer pipe 162 is located outside the transfer chamber. In addition, the fluid distribution device 120 allows for continual fluid replenishing, as required. Fluid replenishment is not limited to the rotational position of the contactor relative to a pool of higher density fluid, as per Haggerty et. al.. In the apparatus described herein, higher density fluid may be provided by the fluid distribution device at any time and at any position during rotation of the contactor.

[0038] In use, a higher density fluid, typically liquid, and most typically waste water containing a high ammonia concentration, is fed into transfer chamber 112. For the sake of clarity, the higher density fluid will, in this description, be referred to as liquid, while lower density fluid will be referred to as gas. However, it should be made clear that this is merely a preferred embodiment of how the present apparatus may be used and there may be situations where other combinations of liquid-liquid, gas-liquid and gas-gas may be treated in the present apparatus. In a typical use, the liquid may be untreated drinking water, municipal, residential, agricultural, or industrial wastewater or storm water.

[0039] As shown in Figure 2, a cleaning device to conduct a high velocity jet of high density fluid 132 may be installed between the contactors. The device is moveable so that the high velocity jet may travel in a radial direction so as to be applied intermittently to all of the rotating contactor surfaces. The timing of the high velocity cleaning jet activity will vary depending on the propensity of foreign material to accumulate in or on the contactor. This device may be automated, or operated manually as dictated by economic considerations.

[0040] The nature of rotating contactor 118 is not particularly restricted, and the selection thereof is within the purview of a person skilled in the art. Rotating contactor 118 is preferably gas penetrable in that gas can cover and/or pass through a large portion of the contactor surface with low head loss. Further, at least a portion of one or more surfaces of the rotating contactor 118 are partially penetrable by the lower density fluid. The term partially penetrable is used herein to include a situation where at least a portion of the surface is penetrable by the lower density fluid and/or a situation where at least a portion of the surface is periodically penetrable by the lower density fluid, i.e. lower density fluid periodically penetrates a portion of the surface of the contactor. Further, one or more (preferably all) surfaces of rotating contactor 118 are preferably fluid permeable.

[0041] In a preferred embodiment, the contactor 118 comprises a spiral sheet that is wound about a central core transfer pipe 162, as described in Haggerty et. al.. In yet another embodiment, rotating contactor 118 is a member formed of foamed, extruded, cast, or expanded media, which has a relatively low resistance to gas flow, and provides a large surface area. It will be understood that the contactor 118 may be formed from any inert material and may be provided in any form that includes a surface area that is operable to contact the fluid. It will therefore be understood that the embodiments described above are not meant to be limiting in any way but serve as examples for different types of contactors that may be used. As an example, the spiral sheet may be formed as described in International Application Publication Number WO/2008/089578 (Haggerty).

[0042] The surface of the contactor 118 that is at least partly penetrable by the lower density fluid and that receives higher density fluid from the fluid distribution device 120 facilitates direct chemical transfer between the lower and higher density fluids when in contact with both. The mass transfer occurs at the interface between the higher and lower density fluids that is defined by the surface of the contactor 118. The loading of the higher density fluid onto the surface of the contactor, through the use of the fluid distribution device 120, provides for a more efficient overall distribution of the higher density fluid which improves the efficiency of the mass transfer between the two fluids.

[0043] Gas is fed into transfer chamber 112 via a gas inlet, not shown. As discussed above current generator 120 creates a current within the gas. Current generator 120 is preferably a blower or fan. Transfer chamber 112 also includes a gas outlet, not shown, as described in Haggerty et al.. It will be apparent to persons skilled in the art that these ports may have dual or multiple functions; an inlet, for example, may be valved so as to operate intermittently as an inlet for one fluid and an outlet for another.

[0044] In use, the high density liquid is fed into the transfer chamber 112 into high density fluid zone 114. As described herein, and in Haggerty et al., the transfer device 110 may include a series of transfer chambers 1 12 through which liquid flows. The progression of the liquid through the transfer chambers is described in Haggerty et al..

[0045] Once high density liquid enters the transfer chamber 112, the pump 121 is operable to pump the liquid into fluid distribution device 120, and in particular through header 125 and out of nozzles 123. The fluid is then transferred directly onto the surface of the rotating contactor 1 18.

[0046] In the embodiment described herein, the movement of the contactor 118 is described as being a rotational movement. In the illustrated embodiments, and the description provided, the contactor is operable to rotate a complete 360°. However, it will be understood that the contactor, in the embodiments described herein, need not be operable to rotate a complete 360° or may be operable rotate 360° but in actual operation may only rotate a portion of the full rotational capacity. It will be understood that the rotational movement of the contactor should allow for movement of the contactor to allow at least a portion of the surface to contact the low density fluid and to receive the high density fluid from the fluid distribution device 120. Partial rotation of the contactor may allow for sufficient fluid to contact the surface of the contactor, through the fluid distribution device 120, and therefore complete rotation may not be required.

[0047] The kinetics of mass transfer allow for some variations on the general operation described herein. Several applications of the transfer apparatus and system described herein are discussed in International Publication Number WO2008/089578 [Haggerty].

[0048] It will be understood that in the case of liquid catalysis, gas flow is optimal as determined by the reaction chemistry desired. Alternatively, a gas may be passed through the coated spiral and a catalytic reaction produced and liquid flow is optional depending on reaction requirements. When the underside of the spiral surface is coated with a catalyst and the gas is catalysed as it passes over this surface, the catalysed gas may then react with the liquid being pumped onto and through the spiral contactor by the spray device and via the contactor rotation.

[0049] In each of the above devices the low density fluid may serve as a stripping fluid which may be either wasted or may pass through a separate contacting device for regeneration so that the low density fluid recirculates and a closed system is produced with respect to the low density fluid. Alternatively in instances where the high density fluid acts as an adsorber it may subsequently pass through a re-generator and be recirculated as determined by the optimal process conditions.

[0050] One further advantage of the device of the present invention is that it allows for the processing of the dense fluid in time rather than space. This gives the designer/operator significant flexibility in controlling the inputs and the outputs of the device which are not easily obtained from a conventional approach. For example when employed for ammonia stripping the retention time and the pH may be adjusted such that the pH of the water leaving the device is within normal release limits without requiring additional processes to adjust the pH downward after stripping. With conventional stripping processes achieving this is often problematic.

[0051] A preferred use of the system of this embodiment of the invention is for stripping and recovering ammonia from a wastewater stream, as discussed in more detail in Haggerty et al..

[0052] Refering to Figure 4 where the axis is vertical, it will be evident to a person skilled in the art that the application of the high density fluid by means of a fluid distribution device applied to the rotating contactor offers advantages over the arrangements of Figures 1 , 2 and 3 where the gas liquid reactions are such that the process objective may be obtained in the time it takes the high density fluid to reach the bottom of the last contactor (this time is controlled by gravity for any given liquid). The advantages are that a single pump is required and in many instances the liquid loading can be higher. The device shown in Figure 4 is an integrated stripper/scrubber. It will be understood that there will be instances where there will be advantages to separating the stripper from the scrubber and interconnecting them by means of ducting. It will also be understood that the center pipe need not serve as a duct, but may be solid. [0053] It will be apparent to a person knowledgeable in reaction kinetics that the flow rates of the different streams and the size of the reaction compartments can be tailored to fit any given set of concentrations and volumes. It is also a feature of this device that it is possible to control the reactor design and operation and the equivalents of base added to the ammonia containing liquids so that the pH within the reactor is adequate for stripping and the pH of the effluent leaving the reactor is between 7 and 9 and does not require the addition of acids for pH adjustment of the effluent prior to further treatment or discharge.

[0054] Insulating the apparatus or system of the present invention can eliminate temperature effects from cold surroundings or mitigate heat losses where operating temperatures are above ambient. Recirculation of the stripping gas also mitigates the negative effects of low temperatures.

[0055] The example of ammonia stripping and acid absorption can be thought of as contacting with no reaction and contacting with a fast reaction. A number of other processes, also described in Haggerty et al., are possible using the system of the present invention, in addition to those specific processes already described.

[0056] As will be clearly understood from the above description, the present invention provides a device that will allow for ammonia stripping from many waste waters without the usual requirement of the addition of chemicals for pH adjustment. This provides the additional benefit of not requiring such additional chemicals, thereby reducing the chemicals used in the process and the cost.

[0057] Further treatment devices may form part of system 110 before or after the series of transfer chambers 112. For example, in the treatment of wastewater, the water may be anaerobically and/or aerobically treated in a reactor (not shown) prior to passing through the series of transfer chambers 112. The wastewater may also be treated upon leaving the last chamber.

[0058] The present invention further provides the use of the transfer apparatus described herein for facilitating transfer of at least one of carbon dioxide, naturally occurring gasses and weak acids from an aqueous wastewater solution into a carrier gas as a means of adjusting the pH. The carbon dioxide may be removed from the gas flow by means of reacting it with a strong base such as sodium hydroxide in a side stream process, or in a scrubbing section within the device. Alternatively a portion of the carbon dioxide containing gas may be vented and the vented gas replaced with fresh gas. Economics will deterimine the method selected. The pH is preferably adjusted to between about 7 and about 10. The pH may be adjusted by the methods described above or by the addition of pH adjusting chemicals.

[0059] As shown in Figures 1 and 4, the transfer apparatus may also include one or more demisters, section 172, located between the different compartments where it is desirable to prevent air born droplets or mist from being transfered, referred herein as the scrubbing section and the stripping section.

[0060] As can be seen in Figures 1, 2 and 3, the transfer apparatus may be mounted on a skid or other means that allows for support of the transfer apparatus.

[0061] While this invention has been described with reference to illustrative embodiments and examples, the description is not intended to be construed in a limiting sense. Thus, various modifications of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to this description. It is therefore contemplated that the appended claims will cover any such modifications or embodiments.

[0062] All publications, patents and patent applications referred to herein are incorporated by reference in their entirety to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference in its entirety.