Patent Publication Number: US-2007102354-A1

Title: System for treating wastewater and a media usable therein

Description:
This application claims the benefit of U.S. Provisional Application No. 60/730,488, filed Oct. 26, 2005. 
    
    
      In the accompanying drawings: 
    
    
       FIG. 1  is a diagram illustrating a wastewater treatment system according to an aspect of the present invention;  
       FIG. 2  is a diagram illustrating, among other things, an example of a biological reactor according to an aspect of the present invention and usable with a wastewater treatment system of  FIG. 1 ;  
       FIG. 3  is a diagram illustrating, among other things, a top view of the biological reactor of  FIG. 2  according to an aspect of the present invention and usable with a wastewater treatment system of  FIG. 1 ;  
       FIG. 4  is a diagram illustrating a wastewater treatment system according to another aspect of the present invention;  
       FIG. 5  is a diagram illustrating, among other things, an example of a biological reactor according to an aspect of the present invention and usable with a wastewater treatment system of  FIG. 4 ;  
       FIG. 6  is a diagram illustrating, among other things, a top view of the biological reactor of  FIG. 5  according to an aspect of the present invention and usable with a wastewater treatment system of  FIG. 4 ;  
       FIG. 7  is a diagram illustrating a cross-section of media for supporting a growth biology within a biological reactor and usable with a biological reactor of  FIG. 1 ,  FIG. 2 ,  FIG. 3 ,  FIG. 4 ,  FIG. 5 ,  FIG. 6 , or any combination of any of the preceding;  
       FIG. 8  is a diagram illustrating a plurality of media for supporting a growth biology within a biological reactor and usable with a biological reactor of  FIG. 1 ,  FIG. 2 ,  FIG. 3 ,  FIG. 4 ,  FIG. 5 ,  FIG. 6 ,  FIG. 7 , or any combination of any of the preceding;  
       FIG. 9  is a diagram illustrating an example of a control algorithm usable with the biological reactor of  FIGS. 1, 2 , and  3  and/or the biological reactor including controlled-reaction-volume modules of  FIGS. 4, 5 , and  6 , either including a media, such as, for example, that shown in  FIGS. 7 and 8 , for supporting a supporting a growth biology;  
       FIG. 10  is a diagram illustrating a cross-section of a prior art media; and  
       FIG. 11  is a diagram illustrating a cross-section of a prior art media. 
    
    
      The present invention is directed towards a number of aspects and/or embodiments connected with a wastewater treatment system and/or a biological reactor usable in a wastewater treatment system and/or a media for supporting a growth biology including, without limitation, any one of a wastewater treatment system, a biological reactor usable in a wastewater treatment system, a media for supporting a growth biology, a method for treating wastewater, a method for supporting a growth biology, or any combination of any of the preceding.  
      Applicant includes the following scenario to provide an understanding of the present invention. It should be understood that the present invention may apply to any one of a wastewater treatment system, a biological reactor usable in a wastewater treatment system, a media for supporting a growth biology, a method for treating wastewater, a method for supporting a growth biology, or any combination of any of the preceding and is not limited to the following scenario.  
      Wastewater treatment is driven by the desire to renovate wastewater before it re-enters a body of water, is applied to the land, is reused, or any combination of any of the preceding to prevent pollution of lakes, rivers, and/or streams. Too many organics, which act as food for a growth biology, and/or too many nutrients, which feed growth biology, in lakes, rivers, and/or streams are able to support growth biology. In turn, growth biology is able to consume available oxygen to, in effect, suffocate wildlife normally found in the in lakes, rivers, and/or streams. Wastewater treatment seeks to reduce this food (organics) and/or these nutrients prior to discharging to levels that permit available oxygen in lakes, rivers, and/or streams to be at levels that support wildlife. Also, wastewater treatment seeks to disinfect (usually with chlorine) to prevent the spread of human pathogens (typically virus and bacteria).  
      Organics are the carbon-hydrogen compounds predominately formed as the result of biological activity. These compounds come in a wide variety of forms. To provide a measure of the amount of organic compounds, the industry has settled on the use of “Biochemical Oxygen Demand” or BOD (normally referred to as five-day BOD, or BOD5), which simply means the quantity of oxygen consumed by a sample spiked with growth biology over a five-day period. It is an indirect measure of the organic content.  
      Nutrients of interest are similar to those used to fertilize a lawn: phosphorus (P) and nitrogen (N). Nitrogen is typically present in the form of ammonia (NH 3 ), which is broken down under aerobic conditions to nitrite and nitrate (NO 2  and NO 3 ). These in turn may be reduced to elemental nitrogen by treating under conditions without oxygen (called anoxic when NO 3  is present). Normally, wastewater is treated under oxic conditions, although certain high strength wastes (typically industrial) are most efficiently treated in the absence of any source of oxygen (air or NO 3 ), a condition called anaerobic. Also, wastewater may be treated in the absence of oxygen in its elemental form, but with NO 2  and/or NO 3  present to provide a source of oxygen, a condition called anoxic.  
      Thus, the goal of wastewater treatment may be summarized as:  
                                       Offending               Constituent   Measured as   Treated by                  Solids   TSS (Total   Settling out in a clarifier           Suspended Solids)       Organics   BOD   Biological oxic (Anaerobic               for high strength)       Phosphorus   P   Biological or by use of               chemicals       Ammonia   NH 3     Biological oxic (reduced to               NO 2 /NO 3 )       Nitrates/Nitrites   NO 2 /NO 3     Biological anoxic       Pathogens   —   Chlorine, Ultraviolet, Ozone                  
 
 The means of treatment is to provide food (BOD), nutrients (P &amp; N, both normally present in sufficient quantities for cell growth), and oxygen for growth biology that does the bulk of the treatment. Wastewater treatment may be thought of as creating a comfortable home for the growth of beneficial growth biology to treat the wastes. To accomplish this end, a wastewater treatment system that typically looks similar to that shown in  FIG. 1  is built to include a biological reactor. 
 
      Sewage is the wastewater released by residences, businesses, and industries in a community. Typical municipal wastewater is about 99.94 percent water, with only about 0.06 percent of the wastewater dissolved and suspended solid material. Industrial wastewater may be considerably higher. Cloudiness of sewage is caused by suspended particles which, in untreated municipal sewage, typically range between about 100 milligrams per liter (mg/l) and 350 mg/l. As noted above, a measure of the strength of the wastewater is BOD (normally referred to as 5 day BOD, or BOD5) that measures the amount of oxygen microorganisms (growth biology) require in five days to break down sewage. Untreated municipal sewage typically has a BOD ranging between about 100 mg/l and 300 mg/l. Pathogens or disease-causing organisms are present in municipal sewage. Coliform bacteria are used as an indicator of disease-causing organisms. Sewage also contains nutrients (such as ammonia and phosphorus), minerals, and metals. Ammonia can range between about 12 mg/l and 50 mg/l, and phosphorus can range between about 6 mg/l and 20 mg/l in untreated sewage.  
      Referring now to  FIG. 1 , wastewater treatment is a multi-stage process (e.g., including preliminary treatment, primary treatment, secondary treatment, final treatment, and, optionally, advanced treatment) to renovate wastewater before it re-enters a body of water, is applied to the land, is reused, or any combination of any of the preceding. The goal is to reduce or remove organic matter, solids, nutrients, disease-causing organisms, and other pollutants from wastewater. Each receiving body of water has limits to the amount of pollutants it can receive without degradation. Each municipal wastewater treatment plant holds a permit listing the allowable levels of BOD, suspended solids, coliform bacteria, and other pollutants. The discharge permits are called NPDES permits, which stands for the National Pollutant Discharge Elimination System. Industrial wastewater treatment plants that have direct stream discharges also have NPDES permits. Industrial plants that discharge into municipal plants have site-specific pretreatment limits.  
      Preliminary Treatment: Preliminary treatment to screen out, grind up, or separate debris is usually the first step in wastewater treatment. Sticks, rags, large food particles, sand, gravel, toys, etc., are removed at this stage to protect the pumping and other equipment in the treatment plant. Treatment equipment such as bar screens, comminutors (a large version of a garbage disposal), and grit chambers are commonly used as the wastewater first enters a treatment plant. The collected debris is usually disposed of in a landfill.  
      Primary Treatment: Primary treatment is usually the second step in treatment and separates suspended solids and greases from wastewater. Wastewater is held in a quiet tank for several hours, allowing the particles to settle to the bottom and the greases to float to the top. The solids drawn off the bottom and skimmed off the top receive further treatment as sludge. The clarified wastewater flows on to the next stage of wastewater treatment. Clarifiers and septic tanks are usually used to provide primary treatment.  
      Secondary Treatment: Secondary treatment is a biological treatment process to remove dissolved organic matter, and often, nutrients from wastewater. Sewage microorganisms (growth biology) are cultivated and added to the wastewater. The microorganisms (growth biology) absorb organic matter from sewage as their food supply. Three approaches are predominately used to accomplish secondary treatment: fixed film, suspended film growth, and lagoon systems.  
      Fixed Film Systems: Fixed film systems grow microorganisms (growth biology) on substrates such as rocks, sand, or plastic. The wastewater is spread over the substrate, allowing the wastewater to flow past the film of microorganisms (growth biology) fixed to the substrate. As organic matter and nutrients are absorbed from the wastewater, the film of microorganisms (growth biology) grows and thickens. Trickling filters, rotating biological contactors, and sand filters are examples of fixed film systems.  
      Suspended Film Growth Systems: Suspended film growth systems stir and suspend microorganisms (growth biology) in wastewater. As the microorganisms (growth biology) absorb organic matter and nutrients from the wastewater, they grow in size and number. After the microorganisms (growth biology) have been suspended in the wastewater for several hours, they are settled out as a sludge. Some of the sludge is pumped back into the incoming wastewater to provide “seed” microorganisms (growth biology). The remainder is wasted and sent on to a sludge treatment process. Activated sludge, extended aeration, oxidation ditch, and sequential batch reactor systems are all examples of suspended film systems.  
      Lagoon Systems: Lagoon systems are normally large, relatively shallow basins that hold the wastewater for a few days to several months to allow for the natural degradation of sewage. These systems may be aerated artificially or take advantage of natural aeration and microorganisms (growth biology) in the wastewater to renovate sewage.  
      Integrated Fixed-Film/Activated Sludge (IFAS) System: IFAS systems combine suspended microorganisms (growth biology) with fixed microorganisms (growth biology). A media of the present invention may be used as a carrier for the fixed microorganisms (growth biology) portion of an IFAS systems.  
      Final Treatment: Final treatment focuses on removal of disease-causing organisms from wastewater. Treated wastewater can be disinfected by adding chlorine or by using ultraviolet light. High levels of chlorine may be harmful to aquatic life in receiving streams. Treatment systems often add a chlorine-neutralizing chemical to the treated wastewater before stream discharge.  
      Advanced Treatment: Advanced treatment is necessary in some treatment systems to remove nutrients from wastewater. Chemicals are sometimes added during the treatment process to help settle out or strip out phosphorus or nitrogen. Some examples of nutrient removal systems include coagulant addition for phosphorus removal and air stripping for ammonia removal.  
      Sludges: Sludges are generated through the wastewater treatment process. Primary sludges, material that settles out during primary treatment, often have a strong odor and require treatment prior to disposal. Secondary sludges are predominately the extra microorganisms (growth biology) from the biological treatment processes. The goals of sludge treatment are to stabilize the sludge and reduce odors, remove some of the water and reduce volume, decompose some of the organic matter and reduce volume, kill disease causing organisms, and disinfect the sludge.  
      Untreated sludges are about 97 percent water. Settling the sludge and decanting off the separated liquid removes some of the water and reduces the sludge volume. Settling can result in a sludge with between about 96 to 92 percent water. More water can be removed from sludge by using sand-drying beds, vacuum filters, filter presses, and centrifuges resulting in sludges with between about 80 to 50 percent water. This dried sludge is called a sludge cake. Aerobic and anaerobic digestion are used to decompose organic matter to reduce volume. Digestion also stabilizes the sludge to reduce odors. Caustic chemicals can be added to sludge, or it may be heat-treated to kill disease-causing organisms. Following treatment, liquid and cake sludges are taken to landfills or usually spread on fields, returning organic matter and nutrients to the soil.  
      Wastewater treatment processes require careful management to ensure the protection of the water body that receives the discharge. Trained and certified treatment plant operators measure and monitor the incoming sewage, the treatment process, and the final effluent.  
      In the following description, like reference characters designate like or corresponding parts throughout the several views. Also in the following description, it is to be understood that such terms as “forward,” “rearward,” “left,” “right,” “upwardly,” “downwardly,” and the like are words of convenience and are not to be construed as limiting terms.  
      Referring now to the drawings in general, and  FIGS. 1 and 4  in particular, it will be understood that the illustrations are for the purpose of describing one or more aspects and/or embodiments of the invention and are not intended to limit the invention thereto. As seen in  FIGS. 1 and 4 , a wastewater treatment system, generally designated  10 , is shown according to the present invention. The wastewater treatment system  10  includes a biological reactor  12 . A number of a media  14  for supporting growth biology are located in the biological reactor  12 . As may be seen in  FIGS. 7 and 8 , each media  14  includes a tubular cross-section  16  and a perturbated outer perimeter  20 . As may be seen in  FIG. 8 , the perturbated outer perimeter  20  may be non-nesting. Also as seen in  FIGS. 7 and 8 , the perturbated outer perimeter  20  may include a stepwise perturbation or a unit stepwise perturbation. The perturbated outer perimeter  20  creates a protected outer surface area  22  for supporting growth biology.  
      Although not necessarily shown in  FIGS. 7 and 8 , in an aspect of the present invention, a tubular cross-section  16  may include any one of an oval cross-section, an elliptical cross-section, a polygonal cross-section, or any combination of any of the preceding. Nonlimiting examples of an oval cross-section may include any one of an egg cross-section, a track cross-section, or any combination of any of the preceding. Nonlimiting examples of an elliptical cross-section include a circular cross-section. Nonlimiting examples of an polygonal cross-section may include any one of a simple polygonal cross-section, complex polygonal cross-section, a convex polygonal cross-section, a concave polygonal cross-section, a concyclic or cyclic polygonal cross-section, a regular polygonal cross-section (e.g., triangle, rectangle, pentagon, hexagon, heptagon, . . . etc. may refer to either regular or non-regular polygons), or any combination of any of the preceding.  
      Turning again to  FIGS. 7 and 8 , in an aspect of the present invention, a media  14  further may include an interior structure  24  capable of creating an interior surface area  26  for supporting growth biology. At least a portion of the interior surface area  26  may include a potion of the perturbated outer perimeter  20 . Also, portions of an interior structure  24  may provide support to the outer perimeter  20 .  
      In an aspect of the present invention, an interior structure  24  may include a distribution within the outer perimeter  20  so as to substantially avoid a bridging of growth biology in a space  34  defined by an interior structure  24  and/or the outer perimeter  20 . Also, portions of the interior surface area  26  may include interior perturbated surface area  32 . Also, an interior perturbated surface area  32  may include a distribution so as to substantially avoid a bridging of growth biology in a space  34 ′ defined by an interior structure  24  and/or the outer perimeter  20 .  
      In another aspect, a perturbated outer perimeter  20  may facilitate a mixing of the media  14 . A mixing of the media  14  may include any one of a tumbling of the media  14 , a rotating of the media  14 , or a tumbling and a rotating of the media  14 . In yet another aspect, a media  14  may include an aspect ratio (nominal length to nominal diameter ratio) of between about 0.3 and about 1. Also, media  14  may be made to any size that would facilitate growth biology, such as, for example, a nominal diameter ranging between about 0.3 inch and about 1.5 inches.  
      Once again turning to  FIGS. 7 and 8 , in an aspect of the present invention, a protected outer surface area  22  for supporting growth biology may include between about 30 to about 70 percent of the exterior surface area of the media  14 . In another aspect, the protected outer surface area  22  for supporting growth biology may include between about 40 to about 60 percent of the exterior surface area. Further, an exterior surface may include an arrangement so as to substantially avoid a bridging of growth biology in a space  34 ′ defined by the perturbated outer perimeter  20 .  
      In an aspect of the present invention, a media  14  is substantially neutrally buoyant in the wastewater being treated. A manner of achieving such neutral buoyancy may be by manufacturing a media  14  so as to have a specific gravity of between about 0.8 and about 1.2. To that end, a media  14  may be manufactured using a polymer, such as, for example, any one of polyolefin, such as, for example, any one of a polyethylene, a polypropylene, a polyvinylchloride, or any combination of any of the preceding. A media  14  may be manufactured by any one of injection molding, extrusion, or the like.  
      Turning now to a biological reactor  12 , as shown in  FIGS. 1, 2 ,  3 ,  4 ,  5 , and  6 , it may further include at least one screen  30  sized so as to facilitate retention of the number of media  14  therewithin. Such screen  30  may be sized with openings smaller than the smaller dimension of a media  14 . For example, an opening of the screen  30  may be about ⅔ of the smaller dimension of a media  14 . A screen  30  may be constructed using a material possessing corrosion resistance, such as, for example, stainless steel. Also, a screen  30  may be constructed of any one of a wedgewire, a round wire, a perforated and expanded metal, or any combination of any of the preceding.  
      A wastewater treatment system  10 , in addition to at least one biological reactor  12 , may further include any one of a chemical supply  38 , one or more clarifier(s)  46  and  50 , a headworks  52 , a filter  48 , a disinfector  54 , an aerator  56 , or any combination of any of the preceding. As shown in  FIGS. 1 and 4 , one clarifier  46  may be upstream from the biological reactor  12  while an additional clarifier  50  may be downstream. A headworks  52  may be upstream from the biological reactor  12  while a filter  48  may be downstream. Also downstream from the biological reactor  12  may be a disinfector  54  and/or an aerator  56 .  
      Applicant contemplates that a wastewater treatment system  10  of the present invention may be any one of a municipal wastewater treatment facility, an industrial wastewater treatment facility, a commercial wastewater treatment facility, a ship wastewater treatment facility, an agricultural wastewater treatment facility, or any combination of any of the preceding.  
      Again turning to a biological reactor  12  as shown in  FIGS. 1, 2 ,  3 ,  4 ,  5 , and  6 , it may further include any one of a mixing device  28 , a controller  40 , a sensor  44 , a controlled-reaction-volume module  60  (e.g., see  FIGS. 4, 5 , and  6 ), a pump, a gas supply  80 , or any combination of any of the preceding.  
      As  FIGS. 1 and 3  are a block diagram of a typical wastewater treatment system  10 , specific unit operations that are not shown may be present.  FIGS. 1 through 8  are not to be encompassing of all options, but for example purposes. The headworks  52  may include screening and grit removal that takes large materials and grit (sand and gravel) out of the wastewater for disposal typically in landfills. Screens typically are metal structures with restricted opening that retain materials over a certain size and that have mechanisms for removing the solids from the surface of the screen. Grit removal is typically controlling velocity to cause the heavier grit (rapidly settling) particles to separate from the main wastewater flow. Some systems bypass this step and go directly on to subsequent unit operations. Lagoon systems are often without headworks, as well as without clarifiers  46  and  50 , that are included in the broad scope of this invention applied to wastewater treatment system  10  in general.  
      Primary clarifier  46  may be any one of a circular tank, a rectangular tank, or any combination of the preceding, which may include one or more bottom scraper mechanisms. The wastewater from the headworks  52  enters the clarifier  46  where relatively quiescent conditions allow slower settling particles to fall to the tank bottom and be removed from the main wastewater flow. These solids typically require further treatment for stabilization prior to ultimate disposal.  
      Wastewater then flows to the biological reactor  12  that may be any one of a tank, basin, a lagoon, or any combination of any of the preceding where biological activity consumes organics and nutrients in the wastewater are accomplishing a major removal function of the wastewater treatment system  10 . These reactors may be aerobic, anoxic, or anaerobic. In an aspect of the present invention, one or more controlled reaction-volume module(s)  60  may be located in a biological reactor  12 .  
      Secondary clarifier  50  receives the effluent from the biological reactor  12  and may be any one of a circular tank, a rectangular tank, or any combination of the preceding, which may include one or more bottom scraper mechanisms. The wastewater from the biological reactor  12  enters the clarifier  34 , where relatively quiescent conditions allow the growth biology grown in the biological reactor  12  and other settleable particles to fall to the tank bottom and be removed from the main wastewater flow. The majority of these settled solids may be returned to the biological reactor  12 . A portion of these solids are wasted from the main wastewater flow and typically require further treatment for stabilization prior to ultimate disposal. Lagoon systems typically eliminate this step.  
      The wastewater proceeds on to an optional filter  48  where the liquid is passed through sand, fabric, or other fine media to remove small remaining suspended solids from the wastewater flow.  
      Due to the pathogens present in domestic wastewater, a disinfector  54  may be provided where oxidizing agents, ultraviolet light, or other bacterial/viral inactivation agents are applied.  
      Re-aerator  56  is another optional unit that may be embodied by aerators in a basin or hydraulic jumps in an effluent structure to promote the increase in dissolved oxygen level in the treated wastewater. The treated wastewater typically then goes to a receiving natural body of water or, in the case of many industrial pretreatment plants, into a receiving sewer.  
      In operation, wastewater containing solids, inorganic and organic components, and/or nutrients enter a wastewater treatment system  10  through headworks  52  that does an initial conditioning step to remove readily separated solids and sand and gravel from the wastewater flow. This simplifies the work required of subsequent unit operations and minimizes equipment wear. The clarifier  46  removes additional settleable solids further reducing the load on subsequent unit operations.  
      The biological reactor  12  may be any one of a tank, a basin, a lagoon, or any combination of any of the preceding, which is either covered or uncovered. Biological conversion is predominately done by microorganisms (growth biology). These reactors may be aerobic where aeration devices are typically used to provide mixing and dissolved oxygen to support the life cycle of the microorganisms (growth biology). Alternatively, these reactors may be anaerobic, where mixing is provided without oxygen. The byproducts of aerobic biological conversion are typically CO 2 , water, and additional cell mass. The byproducts of anaerobic conversion are typically methane, carbon dioxide, water, and additional cell mass. Other biological conversion processes are anoxic, where nitrates and/or nitrites supplant oxygen as the electron donor for metabolic activity and the byproducts are (for nitrified wastewaters) nitrogen gas, water, and additional cell mass and nutrient conversion steps where intermediate reactions take place converting compounds to more environmentally friendly states.  
      The secondary clarifier  50  settles and returns the microorganisms (growth biology) grown in the biological reactor  10  back to the biological reactor  10  to increase the concentration of microorganisms (growth biology) and thereby allow more biological conversion to take place in the biological reactor  12  improving the efficiency and cost effectiveness of the wastewater treatment process.  
      Filters  48  may be used to polish the effluent to further remove the small remain suspended solids and related organics to provide a highly purified effluent. This effluent goes through a disinfector  54  where microorganisms (growth biology)/pathogens are inactivated to provide further protection to the health of the receiving body of water. In some systems, re-aeration  56  is employed to increase the dissolved oxygen level of the wastewater treatment plants effluent to further enhance the health of the receiving body of water  
      Turning now to  FIGS. 2 and 4 , there are shown elevation views of a biological reactor  12 . As noted earlier, a biological reactor  12  may be any one of a tank, a basin, a lagoon, or any combination of any of the preceding. Also, a biological reactor  12  may be any one of covered, uncovered, aerated, not aerated; have natural mixing, induced mixing, or any combination of any of the preceding. The biological reactor  12  is to provide an environment to promote the biological consumption or conversion of pollutants to less harmful states.  
      Contained in a biological reactor  12  is one or more controlled reaction-volume module(s)  60 . These modules  60  may be placed, positioned, and supported in a biological reactor  12  by a variety of mechanisms including any one of floats, side of reactor attachments/supports, bottom of reactor attachments/supports, or any combination of any of the preceding.  
      Biological reactor  12  and/or one or more controlled reaction-volume module(s)  60  include a number of media  14  as described above. Mixing devices  28  are positioned below and/or above of the media  14 . Mixing devices  28  provide the function of controlling the mixing and/or aeration within a biological reactor  12  and/or one or more controlled reaction-volume module(s)  60 . The mixing devices  28  may be individual units or multiple units and may be manifolded-together systems that may incorporate control valving to allow for controlled operation on an independent or group basis.  
      The mixing devices  28  may be a gas or air (pneumatic) mix (See e.g., U.S. Pat. No. 4,595,296 issued Jun. 17, 1986 entitled Method And Apparatus For Gas Induced Mixing And Blending), may be a liquid (hydraulic) mix, or combinations thereof. The mixing device  28  may be powered by a gas supply  80 , which could be a compressor or blower, or powered by pumps or combinations of the two. The source of the gas may be atmospheric air, may be methane from biological activity, or may be from other commercially available gases including nitrogen. The liquid source may be from within the biological reactor  12 ; it may be nitrified effluent, return sludge or external.  
      Optionally, control sensors  44  may be incorporated into a biological reactor  12  and/or one or more controlled reaction-volume module(s)  60 . Control sensors  44  may be used for overall biological reactor  12  and/or one or more controlled reaction-volume module(s)  60  control. A sensor  44  may be of a variety of types including manual in the case of removal sections of media  14  or remote process sensors for such parameters as pH, or time, or temperature, or ammonia, or nitrates, or ORP, or dissolved oxygen, or oxygen uptake rates. Information from sensors  44  may be processed automatically or manually in a controller  20 . The controller  40  processes sensor inputs and controls biological reactor  12  and/or one or more controlled reaction-volume module(s)  60  function by outputs to any one of controls valves, a pneumatic power supply with a control interface, a hydraulic supply with control interface, or any combination of any of the preceding.  
      In operation, wastewater coming into the biological reactor  12  exhibits various characteristics and has various process demands on the treatment system to allow the system to perform as designed. A factor in optimizing the effectiveness of a biological reactor  12  may be to concentrate as many beneficial microorganisms (growth biology) as possible in the space available and to keep them performing at optimum rates. A biological reactor  12  and/or one or more controlled reaction-volume module(s)  60  may provide a controlled environment for a fixed growth high-density biological population. For effectiveness, this population may have a controlled environment. Control parameters include any one of food supply, oxygen, mixing, or any combination of any of the preceding. Controlling these parameters impact other biological variables, including the type of biology the biological reactor  12  and/or one or more controlled reaction-volume module(s)  60  may optimize.  
      By purposely controlling the mixing within a biological reactor  12  and/or one or more controlled reaction-volume module(s)  60 , growth biology thickness may be controlled as well as control of the transport of substrate (food) and oxygen or nitrate (for aerobic or anoxic systems, respectively) within the module. Individual areas of a biological reactor  12  and/or one or more controlled reaction-volume module(s)  60  may be independently and/or periodically highly mixed/aerated to remove older and/or excess growth and provide a thinner new grow biological environment to optimize the biological reactor  12  and/or the performance of one or more controlled reaction-volume module(s)  60 .  
      Worm predation is also an important variable to control in optimizing biological reactor performance where fixed film medias are employed. Reducing the dissolved oxygen level in the media to levels below that supporting worm populations and doing so for a controlled time frame, typically provides worm control. Individual and/or controlled grouping of biological reactor  12  and/or one or more controlled reaction-volume module(s)  60  may operate in this reduced dissolved oxygen mode while the overall biological reactor continues in full functional dissolved oxygen level biological mode. This is opposed to having to take an entire basin to very low to no dissolved oxygen (DO) for extended time frames that could have a negative impact on overall wastewater treatment plant effectiveness. The controllability allows for continual automatic online work control as part of the basic wastewater treatment system  10  operating rationale.  
       FIG. 3  is a plan view showing a biological reactor  12 .  FIG. 6  is a plan view showing four (4) controlled reaction-volume module(s)  60  manifolded together with the provision for valve isolation. Each controlled reaction-volume module  60  contains mixing devices  28  and provision for control sensors  44 . Mixing and/or aeration are provided from pneumatic sources  80  or pumping sources or any combination thereof.  
      Provision may be made to provide commercially available specialized bacteria (and food—wastewater or synthetic) into the module  12  (See e.g., U.S. Pat. No. 5,863,128 issued Jan. 26, 1999 and entitled Mixer-Injectors With Twisting And Straightening Vanes). This may be referred to as bioaugmentation. Some example of products for municipal wastewater treatment and related areas available from Novozymes Biologicals Inc. Salem, Va., USA that may be used include:  
                                   BI-CHEM ® 2000 series   Target                  BI-CHEM ® 2000GL   Fats, oils, and grease       BI-CHEM ® 2003MS   Cold weather BOD       BI-CHEM ® 2006RG   Surfactant assisted for severe grease       BI-CHEM ® 2008AN   Anaerobic digester grease       BI-CHEM ® 2009GT   Anaerobic lift stations       BI-CHEM ® 2010XL   Treatment plant optimization       BI-CHEM ® 1010   Nitrification       BI-CHEM ® Odor Controller   Non-sulfide odors       BI-CHEM ® Nitraid ™   Sulfide control                  
 
      Some example of products for industrial wastewater treatment and related areas available from Novozymes Biologicals Inc. Salem, Va., USA that may be used include:  
                                   BI-CHEM ® 1000 series   Target                  BI-CHEM ® 1000DL   Industrial drain lines       BI-CHEM ® 1002CG   Phenolics and related compounds       BI-CHEM ® 1003 FG   Food processing       BI-CHEM ® 1004TX   Surfactants       BI-CHEM ® 1005PP   Pulp and paper       BI-CHEM ® 1006KT   Acetone and related ketones       BI-CHEM ® 1008CB   General chemical       BI-CHEM ® 1738CW   Cold weather BOD       BI-CHEM ® ABR Hydrocarbon   Petroleum hydrocarbons       BI-CHEM ® 1010N   Nitrification       BI-CHEM ® Odor Controller   Non-sulfide odors       BI-CHEM ® Nitraid ™   Alternate electron acceptor       BI-CHEM ® MicroTrace   Biological tracer                  
 
 This bioaugmentation may be used, for example, in lagoons where it is difficult to concentrate microorganisms or for enhancing nitrification or removal of other target compounds. 
 
      In an aspect as shown in  FIGS. 1, 2 ,  3 ,  4 ,  5 , and  6 , a controller  40 , in conjunction with a pump and/or a aeration mechanism  80 , is configured to be capable of creating an environment within the any one of a portion of a biological reactor  12  and/or one controlled-reaction-volume module  60  that may be alternated among any one of aerobic, anoxic, anaerobic, or any combination of any of the preceding. In another aspect as shown in  FIGS. 1, 2 ,  3 ,  4 ,  5 , and  6 , a controller  40  communicates with the at least one mixing device  28 . For example, a controller  40  may be capable of controlling a dissolved oxygen concentration within a biological reactor  12 .  
      Examples of a suitable controller  40  may include any one of a mechanical controller, operated manually controller, a electromechanical controller, an electronic controller, or any combination of any of the preceding. In an aspect of the invention, a controller  40  may capable of facilitating control of at least one growth-biology predator if a predator may be an issue.  
      Any of a number of type or kind of controllers  40  may be used such as, for example, programmable logic controllers (PLCs), manually operated controllers, time controllers, electrical controllers, mechanical controllers, electro-mechanical controllers, pneumatic controllers, or any combination of any of the preceding. Also, a controller may be integrated into a main and/or sub plant controller without a local panel. In this manner, rather than buying a controller  40 , an integration of the control of the operation of a biological reactor  12  and/or a controlled-reaction-volume module  60  into the main and/or sub plant controller may be accomplished.  
      When present, the at least one controller  40  may communicate at least with the at least one mixing device  28 . Also, the controller  40  may communicate with valves (e.g., actuated pneumatically, electrically, mechanically, hydraulically, electro-mechanically, and combinations thereof) such as solenoid valves, and/or pumps and/or sensors either located within and/or without a biological reactor  12  and/or a controlled-reaction-volume module  60 .  
      A biological reactor  12  may include at least one and, optionally, more sensors  44 . One example of a suitable sensor  44  is one capable of measuring biological activity. Another example of a suitable sensor  44  is one capable of measuring pH. Yet another example of a suitable sensor  44  is one capable of measuring dissolved oxygen (DO). Still another example of a suitable sensor  44  is one capable of measuring at least one enzyme level, such as, for example, any one of adenosine triphosphate (ATP), adenosine diphosphate (ADP), oxidation-reduction potential (ORP) ammonia, nitrates, nitrites, or any combination of any of the preceding. If appropriate, a sensor  44  may be capable of indicating a presence of a growth-biology predator, such as, for example, a worm. In an aspect, a sensor  44  may be as simple as a coupon.  
      Now turning to  FIGS. 4, 5 , and  6 , which show a biological reactor  12  further including a controlled-reaction-volume module  60  and a number of a media  14  for supporting a growth biology within the controlled-reaction-volume module  60  within the biological reactor  12 . Such a biological reactor  12  further may include at least one mixing device  28  capable of communicating a fluid to the at least one controlled-reaction-volume module  60 . In an aspect, a mixing device  28  (e.g., high momentum mixer) communicates a fluid to a controlled-reaction-volume module  60 . It will be appreciated that one controlled-reaction-volume module  60  channels or may be capable of directing a flow of fluid in the vertical direction. A controlled-reaction-volume module  60  may include a partially vertically enclosed partition  62 . Alternatively, a controlled-reaction-volume module  60  may include a substantially completely vertically enclosed partition  62 . In either case, a controlled-reaction-volume module  60  further may include a flow director  64  that may extend at least a portion of a partition  62  beyond the media  14 . As with a screen  30 , a controlled-reaction-volume module  60  may be sized with openings smaller than the smaller dimension of a media  14 . For example, an opening of the controlled-reaction-volume module  60  may be about ⅔ of the smaller dimension of a media  14 . A controlled-reaction-volume module  60  may be constructed using a material possessing corrosion resistance, such as, for example, stainless steel. Also, controlled-reaction-volume module  60  may be constructed of any one of a wedgewire, a round wire, a perforated and expanded metal, or any combination of any of the preceding.  
      It will be appreciated that an environment within a controlled-reaction-volume module  60  may be controlled to be any one of one aerobic, anoxic, anaerobic, or any combination of any of the preceding. Further, such environment may be alternated among any one of aerobic, anoxic, anaerobic, or any combination of any of the preceding.  
      In a biological reactor  12 , a controlled-reaction-volume module  60  further may include a support mechanism  66 , such as, for example, any one of a flotation mechanism, a floor stand, a suspension mechanism, or any combination of the preceding. For example, a suspension mechanism may be any one of within the biological reactor  12 , from a top of the biological reactor  12 , or any combination of the preceding.  
      Returning to  FIGS. 4 and 5 , a biological reactor  12  further may include at least one additional controlled-reaction-volume module  60 ′. In such a case, each of the at least two controlled-reaction-volume modules ( 60  and  60 ′) may be capable of being alternated among any one of aerobic, anoxic, anaerobic, or any combination of the preceding. Such alternating among any one of aerobic, anoxic, anaerobic, or any combination of the preceding may be done independently for each of the at least two controlled-reaction-volume modules  60 . Thus, it will be appreciated that a biological reactor  12  may include a plurality of controlled-reaction-volume modules  60 ,  60 ′,  60 ″, etc. Again, the plurality controlled-reaction-volume modules  60 ,  60 ′,  60 ″, . . . etc. may be capable of being alternated among any one of aerobic, anoxic, anaerobic, or any combination of the preceding. Once again, such alternating among any one of aerobic, anoxic, anaerobic, or any combination of the preceding may be independent for each of the plurality of controlled-reaction-volume modules  60 ,  60 ′,  60 ″, . . . etc.  
      Turning now to growth biology, in an aspect, a thickness of growth biology may be such that it encourages autotrophic organisms. For example, a thickness of growth biology may be such that there is a preponderance of aerobic organisms versus anaerobic organisms. Alternatively, a thickness of growth biology may be such that it is capable of substantially maintaining a surface area of the media  14 .  
      Returning to the mixing device  28  of  FIGS. 1, 2 ,  3 ,  4 ,  5 , and  6 , it may be a bubble generator including any one of a large coarse bubble generator, a medium bubble generator, a fine bubble generator, or any combination of any of the preceding. In an aspect, a mixing device  28  may be a high momentum including any one of a jet mixer, a jet aerator, a mechanical mixer, a pump, or any combination of any of the preceding.  
      In another aspect as depicted in  FIGS. 2, 3 ,  5 , and  6 , a biological reactor  12  further may include an aeration mechanism  80 , such as, for example, a bubble generator.  
      In operation, wastewater enters the biological reactor  12  for treatment and flow onto the next unit operation. Suspended growth microorganisms (growth biology) grow, are concentrated by returning underflow from the secondary clarifier  34 , and consume pollutants. In order to enhance the removal characteristics of the biological reactor  12 , fixed film media is added to the biological reactor  12  to increase the biological effectiveness and provide enhanced biology and control of biology. Without limitation, typical applications may include: anoxic, aerobic, heterotrophic growth, and nitrifying organisms.  
      Anoxic: Biological reactor  12  and/or controlled-reaction-volume module  60  have flow induced without the introduction of dissolved oxygen. An enhanced function is for returned nitrified effluent to be returned directly into the biological reactor  12  and/or controlled-reaction-volume module  60  to both facilitate mixing and biological conversion.  
      Aerobic: Aeration is conducted in the basin by conventional means including diffused aeration and surface mechanical aeration. Media  14  of biological reactor  12  and/or controlled-reaction-volume module  60  grows high densities of desirable microorganisms (growth biology). Flow is induced through the biological reactor  12  and/or controlled-reaction-volume module  60  by the mixing device  28 . Due to the high rate of microbial activity, high growth rates may occur, resulting in thick film growth on the fixed film media. By controlling the mixing intensities within the biological reactor  12  and/or controlled-reaction-volume module  60  through control of the mixing device  28 , the film thickness and resultant biological effectiveness may be controlled and optimized.  
      Biological reactor  12  and/or controlled-reaction-volume module  60  may have high-rate mixing cycles independently or in groups programmed into the controller  40  based upon sensor  44  to purge excess growth to maintain overall operational maximum efficiencies.  
      Biological reactor  12  and/or controlled-reaction-volume module  60  may also individually or in groups be subjected to low to no dissolved oxygen environments by stopping mixing devices  28 . This condition promotes the worm cure environment on a module-specific basis. The worms will release and exit the module. Excessive worm growth may be especially detrimental to modules specifically dedicated to nitrification.  
      Biological reactor  12  and/or controlled-reaction-volume module  60  may also individually or in groups be subjected to low to no dissolved oxygen environments by stopping mixing devices  28 . This condition may be utilized to force bacteria to use the ammonia converted during aerobic operation into nitrites/nitrates as the electron donor, thereby further reducing nitrogen compounds for more complete treatment.  
      Heterotrophic growth: Heterotrophic growth is very fast-growing and typically focused on consumption of organics quantified as BOD (Biochemical Oxygen Demand). Worms for media  14  of the present invention in heterotrophic applications typically are not a problem and may actually be beneficial due to their reduction in net waste sludge.  
      Nitrifying organisms: Nitrifying organisms are autotrophic and necessary for many current advanced wastewater treatment applications. Nitrifiers are relatively slow-growing, and the predation on them by worms can adversely affect population densities needed for effective treatment.  
      The ability of biological reactor  12  and/or controlled-reaction-volume module  60  to control the reactor environment (dissolved oxygen content in this case) provides for controlling the worm population independent of entire basin environment, and thereby optimizes efficiencies of basin utilization and bacterial diversity.  
      For example, in a logic sequence for biological reactor  12  and/or controlled-reaction-volume module  60  operation, one module is in “worm cure mode”. This module may have no mixing. Dissolve oxygen level are “none non-detect”. The timer puts this mode into effect for 18 hours. The timer also reinitiates this mode again in 12 days to capture the inactivation of the reproductive life cycle of the undesired organism.  
      The controller  40  initiates these cycles to individual modules or groups of modules to minimize the number of modules that are off aerobic line at any one time.  
      Based upon sensor  44  inputs, mixing is periodically significantly increased to promote removal of excessive biological growth and maintain optimum reactor effectiveness. Controller  40  maintains continuity, hierarchy of operations, and control by operations.  
       FIG. 10  represents the logic pathway of the controller  40  and sensors  44 . The logic pathway is initiated at  400 . A signal passes from  410  to  402  and then to  404 . Boxes  402  and  404  represent sensors that can detect settings such as biological activity, pH, dissolved oxygen, enzymes, ATP, ADP, Ammonia, Nitrates, ORP, or predator presence in order to vary the activity of the mixing device  28  through the controller  40 . Box  406  is a decision point. If a sensor  44  is triggered, then the signal moves to Box  408  and eventually loops to Box  402 . Box  408  changes the speed of the mixing device  28  from off to maximum depending on the value the sensors represented by  402  and  404  detected. The signal then loops back through to  402  to detect if a sensor has been triggered again.  
      Accordingly, one aspect of the present invention is to provide a wastewater treatment system including a biological reactor. A number of a media for supporting growth biology are located in the biological reactor. Each media includes a tubular cross-section and a perturbated outer perimeter. The perturbated outer perimeter creates a protected outer surface area for supporting growth biology.  
      Another aspect of the present invention is to provide a biological reactor including a number of a media located in the biological reactor and for supporting a growth biology. Each media includes a tubular cross-section and a non-nesting perturbated outer perimeter. The non-nesting perturbated outer perimeter creates a protected outer surface area for supporting a growth biology.  
      Still another aspect of the present invention is to provide a wastewater treatment system including a biological reactor. A number of a media for supporting a growth biology are located in the biological reactor. Each media includes a tubular cross-section and a non-nesting perturbated outer perimeter. The non-nesting perturbated outer perimeter creates a protected outer surface area for supporting a growth biology. At least one screen sized so as to facilitate retention of the number of media within the biological reactor may also be provided.  
      Turning now to  FIG. 8  that shows a number of media  14  of the present invention and that outer surface area  22  of each media  14  is protected from collisions. Further,  FIG. 8  shows that a media  14  of the present invention may include a non-nesting perturbated outer perimeter  20 . The media  14  of  FIG. 8  can be contrasted with the prior art media shown in  FIGS. 10 and 11  because all outer surfaces may come into contact with other outer surfaces and, thus, are kept free from growth biology through growth biology wear. Furthermore, the media  14  of the present invention have a design allowing a good transfer of oxygen and organic matter to growth biology.  
      Certain modifications and improvements will occur to those skilled in the art upon a reading of the foregoing description. By way of example, a radial section connecting a perimeter  20  to the outer surface area  22  may be angled in a manner offset from the centerline of a media  14  to create a larger outer surface area  22  than would occur if the forgoing radial section were in a line intersecting the centerline of the media  14  as shown in  FIG. 7 . Also, a perturbated outer perimeter  20  may be perturbed as a spiral form or spiral structure or helix to create a protected outer surface area  22  for supporting growth biology that lies on a surface of the media  14 , so that its angle to a plane perpendicular to the axis of the media  14  is substantially constant. In this manner, surface area and/or mixing may be increased. It should be understood that all such modifications and improvements have been deleted herein for the sake of conciseness and readability but are properly within the scope of the following claims.