Abstract:
A batch treatment system that provides wastewater treatment one batch at a time, rather than a continuous flow process. In a basic embodiment, the batch treatment system incorporates two zones: (1) a solids separation zone, and (2) an advanced oxidation zone. More advanced embodiments add a filtration zone after separation and before advanced oxidation. The batch treatment system is particularly useful in applications such as ships because (1) reduced size and weight requirements, (2) the reduction of sludge and organic solids saves space and energy and disposal costs, and (3) the reduction of odors permits shipboard treatment rather than holding in tanks for later discharge.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     The present application claims priority to co-pending U.S. provisional patent application entitled “Method and Apparatus for Advanced Oxidation Sequence Batch Process for Wastewater Treatment,” having Ser. No. 60/757,659, filed on Jan. 10, 2006, which is entirely incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates generally to wastewater treatment systems, and more particularly wastewater treatment systems where holding large volumes of sludge for later disposal is difficult. As such, this invention particularly relates to waste water treatment for ships, off-shore structures and platforms other large transportation vehicles, mobile/portable treatment systems (i.e., military support, disaster relief, etc.), remote treatment systems (i.e. highway rest stops, campgrounds, etc.), industrial wastewater treatment, food processing, dairy and other light industrial wastewater treatment applications.  
         [0004]     2. Discussion of the Related Art  
         [0005]     Land-based wastewater treatment solutions tend to occupy relatively large spaces to effectuate wastewater treatment. Space, however, is a premium on transportation vehicles (like cruise ships), mobile treatment systems (such as used in military support), and remote treatment systems (like campgrounds), as well as other similarly situated treatment scenarios.  
         [0006]     Wastewater treatment systems have been disclosed in the following United States or foreign patents: U.S. Pat. No. 3,822,786 (Marschall), U.S. Pat. No. 3,945,918 (Kirk), U.S. Pat. No. 4,053,399 (Donnelly et al.), U.S. Pat. No. 4,072,613 (Alig), U.S. Pat. No. 4,156,648 U.S. Pat. No. (Kuepper), U.S. Pat. No. 4,197,300 (Alig), U.S. Pat. No. 4,214,887 (van Gelder), U.S. Pat. No. 4,233,152 (Hill et al.), U.S. Pat. No. 4,255,262 (O&#39;Cheskey et al.), U.S. Pat. No. 4,961,857 (Ottengraf et al.), U.S. Pat. No. 5,053,140 (Hurst), U.S. Pat. No. 5,178,755 (LaCrosse), U.S. Pat. No. 5,180,499 (Hinson et al.), U.S. Pat. No. 5,256,299 (Wang et al.), U.S. Pat. No. 5,308,480 (Hinson et al.), U.S. Pat. No. 6,811,705 (Puetter), EPO 261822 (Garrett), WO 93/24413 (Hinson) and U.S. Pat. No. 6,195,825 (Jones). None of these references, however, disclose the aspects of the current invention.  
       SUMMARY OF THE INVENTION  
       [0007]     The invention is summarized below only for purposes of introducing embodiments of the invention. The ultimate scope of the invention is to be limited only to the claims that follow the specification.  
         [0008]     Generally, the present invention is incorporated in a batch treatment system for use in a wastewater treatment process (referred to herein as the “batch treatment system”). In a basic embodiment, the batch treatment system incorporates a solids separation zone and an advanced oxidation zone. The solids separation zone includes a clarifier, a flocculator, and an ozone infusing subsystem and is in periodic fluid communication with the advanced oxidation zone. The advanced oxidation zone includes a reactor housing fluidized media and a recirculation subsystem that incorporates the use of ultraviolet light and ozone. Other embodiments include the use of filtration and ultrafiltration. In operation, wastewater does not continuously flow through the solids separation zone or the advanced oxidation zone but is treated one batch at a time before passing to the next zone.  
         [0009]     One advantage of the batch treatment system is that it requires virtually no chemical additions and no chlorine.  
         [0010]     Another advantage of the batch treatment system is no biological sludge production.  
         [0011]     Another advantage of the batch treatment system is that it can be configured for a small footprint.  
         [0012]     Another advantage of the batch treatment system is that it can be configured for use in small vessels (i.e., 1 to 150 people).  
         [0013]     Another advantage of the batch treatment system is that it produces treated effluent minutes after start-up.  
         [0014]     Another advantage of the batch treatment system is that it can be configured to be compact in size, simple in design, inexpensive to operate, skid mounted, operate in a marine environment, and is hatchable through most common ship passages.  
         [0015]     Another advantage of the batch treatment system is that it permits real-time effluent monitoring.  
         [0016]     Another advantage of the batch treatment system is that it is simple to operate as well as it has low operating and maintenance costs.  
         [0017]     Another advantage of the batch treatment system is that is can treat blackwater and graywater wastewater to legally dischargeable environmental standard.  
         [0018]     Another advantage of the batch treatment system is that is can be used use in the marine environment aboard ships and offshore structures,  
         [0019]     Another advantage of the batch treatment system is that it is equally useful in land based stationary and mobile applications (i.e. truck or trailer mounted).  
         [0020]     The description of the invention that follows, together with the accompanying drawings, should not be construed as limiting the invention to the example shown and described, because those skilled in the art to which this invention pertains will be able to devise other forms thereof within the ambit of the appended claims. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]      FIG. 1  illustrates a preferred flow diagram for a batch treatment system embodiment.  
         [0022]      FIG. 2  illustrates a front elevation of a batch treatment system embodiment.  
         [0023]      FIG. 3  illustrates a basic embodiment of the system (i.e., no filtration).  
         [0024]      FIG. 4  illustrates a medium treatment embodiment of the system with filtration  
         [0025]      FIG. 5  illustrates an advanced treatment embodiment of the system using ultrafiltration.  
         [0026]      FIG. 6  illustrates a preferred stirred advanced oxidation batch reactor. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0027]     The descriptions below are merely illustrative of the presently preferred embodiments of the invention and no limitations are intended to the detail of construction or design herein shown other than as defined in the appended claims. In this specification, the term “advanced oxidation” refers to a process that typically involves the generation and use of the hydroxyl free radical (OH − ) as a strong oxidant to destroy compounds that cannot be oxidized by conventional oxidants such as oxygen, ozone, and chlorine.  
         [0028]     The batch treatment system can be embodied in at least three different levels of treatment. A basic system embodiment  100  would comprise a solids separation zone  110  and an advanced oxidation zone  140 . A medium treatment embodiment  150  would comprise a solids separation zone  110 , a filtration zone  120 , and an advanced oxidation zone  140 . An advanced treatment embodiment  160  would comprise a solids separation zone  110 , a filtration zone  120  that includes an ultrafiltration unit  130 , and an advanced oxidation zone  140 . Embodiment selection is based upon quality of treated water desired. For example, the basic system embodiment  100  provides minimal regulatory compliance for discharge into the environment, and the advanced treatment embodiment  160  provides a high quality effluent suitable for reuse as technical water (wash down, laundry, flushing systems).  
         [0029]     The batch treatment system processes wastewater using a sequenced batch process. In a sequence batch process, flow is neither continuously entering nor leaving the system (i.e. flow enters, is treated, and then is discharged to the next step).  FIG. 1  provides a functional diagram of an embodiment of the batch treatment system. Batch processes are used in the solids separation zone  110  and advanced oxidation zone  140 . The filtration zone  120  is a flow through process moving wastewater from one batch treatment process to the next. The filtration zone  120  is only used in the medium treatment embodiment  150  and the advanced treatment embodiment  160 . A filtration zone  120  it is not used in the basic system embodiment  100 .  
         [0030]     As shown in  FIG. 3 , the basic batch treatment system  100  treats wastewater as follows. Wastewater is initially held in a storage tank  10 . From the storage tank  10 , wastewater is transferred to a solids separation zone  110 . There are multiple ways to separate solids. For the batch treatment system, however, it is preferred that the solids separation zone  110  comprises a pump  14 , a flocculator  26 , a clarifier  30 , and an ozone infusing subsystem  28  in fluid communication with each other. The preferred ozone infusing subsystem  28  would include a gas dissolving pump  30  and an ozone generator  34 .  
         [0031]     The pump  14 , preferably a macerating grinder pump, transfers the wastewater from the storage tank  10  to the flocculator  26 . In doing so, the pump  14  can homogenize the wastewater to an optimum particle size compatible with the clarifier  30  and fills the clarifier  30  to a predefined level. An example of a macerator pump  26  for a 5-gpm system is manufactured by Barnes, model number DGV2042L.  
         [0032]     Just prior to the clarifier, a small mixture of ozone gas and air  32  is streamed into the wastewater as it passes through the flocculator  26  by the gas-dissolving pump  30 . An ozone generator  34  can be utilized to provide the ozone. An example of a gas-dissolving pump  30  is made by Nikuni, model M25NPD-15Z. This step facilitates separation since the air will adhere to particles suspended in the wastewater, causing them to become positively buoyant. Alternatively a coagulant, preferred is a solution of aluminum chlorohydrate, may be added by dosing pump or other means to attain an optimum concentration (roughly 30-ppm) to assist flocculation and coagulation of solids.  
         [0033]     While many types of clarifiers are available, the preferred clarifier is a stainless steel hydraulic-lift dissolved air flotation device having a cone-shaped top, which is referred to in this specification as a solids separator  40 . Effluent from the flocculator  26  flows into the solids separator  40  at the inlet  42 .  
         [0034]     In the solids separator  40 , some of the solids in the wastewater entering inlet  42  have an initial positive buoyancy causing them to float to the top, while the balance is maintained in solution and those that higher density begin to fall to the bottom of the solids separator  40 . A stream of wastewater is removed from the solids separator  40  at a side outlet  46 , infused with ozone gas by the gas-dissolving pump  30 , recirculated to the flocculator  14 , and then back into the solids separator  40  at inlet  42 . This continual addition of ozone reacts the organic solids material in the solids separator  40  increasing its density while decreasing the total weight of solids material.  
         [0035]     Alternatively, this action may be augmented by introducing recirculated water with dissolved ozone directed into pipe diffusers  45  (source of this water is same as for the flocculator  26 ) near the bottom of the solids separator  40 . When released from the pipe diffusers, dissolved ozone forms very fine bubbles that move upwards, imparting an upward velocity to the fluid. As ozone contacts solid material it tends to agglomerate onto its surface imparting a slight positive buoyant force and begins to oxidize organic material. This combination of upward fluid velocity and positive buoyancy floats solids to the surface.  
         [0036]     Continual addition of aerated and ozonated recirculated water into the solids separator  40  through the flocculator  26 , and alternatively the pipe diffusers  45 , continuously mixes the material within the solids separator  40  continually oxidizing and reacting the organic material. At periodic intervals the recirculation stream is stopped and the solids separator  40  enters a period of quiescence. During this time the reacted solids tend to sink to the bottom of the device leaving a small blanket of floating solids and foam at the top and a well defined clarified liquor zone in the middle. Experiments have shown that between 70 and 80% of the wastewater may be decanted as clarified liquor when using this method. The clarified liquid is decanted from the solids separator  40  from a side outlet  46  and directed for further treatment.  
         [0037]     The remaining solids and floating material in the solids separator  40  is either retained within the solids separator  40  for further processing, or pumped via bottom outlet  44  to storage tanks for subsequent disposal. In the case of a 5-gpm system (nominal, flow averaged over a twenty four hour period) an example of a solids separator  40  is a two-foot diameter 316 stainless steel tank having a volume of approximately 118-gallons with a design hydraulic residence time of 23 minutes available from Navalis Environmental Systems as part number TK24-004-01.  
         [0038]     In the basic system embodiment  100 , wastewater (clarified liquor  48 ) is pumped from the solids separation zone  110  to the advanced oxidation zone  140 . In the medium treatment embodiment  150 , wastewater (clarified liquor  48 ) is pumped from the solids separation zone  110  through the filtration zone  120  before being directed to the advanced oxidation zone  140  as shown in  FIG. 4 . In the advanced treatment embodiment  160 , wastewater (clarified liquor  48 ) is pumped from the solids separation zone  110  through the filtration zone  120 , which includes an ultrafiltration unit  130 , before being directed to the advanced oxidation zone  140  as shown in  FIG. 5 .  
         [0039]     After the clarified liquor  48  empties from the solids separator  40 , the hydraulic separator  40  is then refilled from the storage tank  10  as described above and the batch process begins again.  
         [0040]     For the medium treatment embodiment  150 , the preferred filtration zone  120  comprises an ozone resistant tubular backwashable filter  122 , such as model AQM 30 manufactured by Wastewater Resources Incorporated. For the advanced treatment embodiment  160 , it is preferred that filtration zone  120  additionally comprise an ultrafiltration unit  130  and a permeate flush tank  132 . It is preferred that the ultrafiltration unit  130  be pressure fed ozone resistant tubular ceramic ultrafiltration membranes, such as the Kerasep Series manufactured by Novasep Orelis. System capacity may be increased by adding additional modules. The ultrafiltration unit  130  should be periodically flushed with water produced by the ultrafiltration unit  130  and stored in the permeate flush tank  132 .  
         [0041]     The preferred advanced oxidation zone  140  comprises a reactor vessel  50 , an ultraviolet (UV) unit  52 , and an ozone dissolving pump  54 . Within the reactor vessel  50  are neutrally buoyant media  310 . The purpose of the media  310  is to provide sufficient surface area for the interaction and oxidation of dissolved ozone and soluble and insoluble organic material.  
         [0042]      FIG. 6  illustrates a preferred reactor vessel  50 , a stirred reactor  300 . Referring to  FIG. 6 , the stirred reactor  300  comprises two cylindrically shaped chambers: a cylindrical acceleration chamber  302  and a fluidized media chamber  304 . The two chambers are mounted coaxially with respect to each other (i.e., one inside the other). Two washer-shaped perforated plates  306  on either end cap the fluidized media chamber  304 . One perforated plate is mounted near the top of the stirred reactor  300  and the other near the bottom. The volume between the perforated plates  306  houses fluidized media  310 . These upper and lower perforated plates  306  hold the fluidized media  310  in place and away from inlet and outlet ports. It is preferred that the perforations be sized to allow maximum flow while retaining the fluidized media  310  between perforated plates  306 .  
         [0043]     The cylindrical acceleration chamber  302  is smaller in cross section and mounted between the perforated plates  306 . The preferred stirred reactor  300  has inlet ports  308  and outlet ports  309  for admitting and exhausting the liquid. At the top of the stirred reactor  300 , a mixer  312  with a shaft  314  containing multiple blades  316  passes down though the cylindrical acceleration chamber  302 . The mixer  312  moves fluid in the cylindrical acceleration chamber  302  down and out to the fluidized media chamber  304  through the bottom perforated plate  306 . After passing through the bottom perforated plate  306 , water moves up through the fluidized media chamber  304  and then back into the top of cylindrical acceleration chamber  302  to begin the process again.  
         [0044]     Ozone enriched fluids react with dissolved ozone and tiny, outgassed ozone bubbles which have formed on the fluidized bed, walls of the chamber, and float freely within the chamber. This enhanced batch oxidation reactor allows for advanced treatment in a small space. The stirred reactor  300  can be used alone, in series or in parallel. When connected in series, the outlet port  309  of one stirred reactor  300  can be connected to the series inlet port  308  if the second stirred reactor  300 . A suitable example of a preferred stirred reactor  300  for a 5-gpm unit is a two-foot diameter 316 stainless steel tank having a volume of approximately 118-gallons with a design hydraulic residence time of 23 minutes available from Navalis Environmental Systems as part number TK24-003-01.  
         [0045]     Water is continuously pumped out of the stirred reactor  300  and through an ultraviolet light disinfection unit, or UV unit  52 . A medium pressure, high intensity unit produces polychromatic light, which destroys residual organic material, and further disinfects the wastewater. The UV unit  52  preferably features an automatic cleaning wiper (as controlled by a PLC). Light produced by the UV unit also enhances the advanced oxidation reaction by transforming any residual ozone into fast reacting species, such as hydrogen peroxide and hydroxyl radicals further consuming any residual organic material. In the preferred 5-gpm variant of this system, an example of a suitable UV unit  52  is manufactured by Hyde Marine, part number InLine 20.  
         [0046]     Following the UV unit  52 , water is directed to a gas dissolving pump  54  where ozone gas is dissolved in the water and it is directed back into the stirred reactor  300 . This recirculation loop  64  for advanced oxidation zone  140  is continuous throughout the batch process.  
         [0047]     After the design hydraulic residence time has been reached, a discharge valve  66  is opened draining the stirred reactor  300 . An alternate embodiment would control the discharge cycle through automatic measurement of effluent quality by comparison of oxidation-reduction potential and fluid turbidity. Treated water is then either pumped directly overboard, or pumped to onboard ship storage tanks for eventual discharge. After the stirred reactor  300  is emptied, the batch being treated in the solids separator  40  is pumped into the stirred reactor  300  to begin the process anew.  
         [0048]     An ozone generator  34  produces gaseous ozone. For the 5-gpm preferred embodiment, Pacific Ozone Model SGA24 with a rating of sixty grams/hour is used. If available, the preferred source of air to the ozone generator is from ship service oil free compressed air. However, if not available, a self-contained air compressor can be provided as an integral part of the ozone generator.  
         [0049]     An ozone gas destruction system  60  is provided to decompose residual ozone gas to oxygen through catalytic action. Using a blower  61  this system draws a slight vacuum from the top of tanks  40  and  300  and draws the gases through an ozone destruct device  62  before discharging into an installed ventilation system.  
         [0050]     Although the invention has been described in detail with reference to one or more particular preferred embodiments, persons possessing ordinary skill in the art to which this invention pertains will appreciate that various modifications and enhancements may be made without departing from the spirit and scope of the claims that follow.