Abstract:
In a process for treating effluent water, a stream of effluent water is fed to a porous ceramic media filled reactor. Organic and inorganic impurities are absorbed and/or oxidized from the effluent water into the media and/or off-gases. The remainder of the effluent water stream is dispensed from the reactor in an outlet stream suitable for direct discharge to the sea or for recycling without incurring the disadvantages of generating a solid sludge. The reactor includes a chamber containing activated media, such as pellets of porous ceramic material. The pellets are stored in a vertical stacks of sub chambers defined by horizontal perforated trays and/or in a horizontal chains of sub chambers defined by vertical perforated baffles.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to waste water treatment and more particularly concerns the treatment of hazardous waste waters such as the effluent water discharged from hydrocarbon processing facilities, general industrial facilities or contaminated municipal water supplies. 
     The effluent water discharging from a hydrocarbon processing facility contains oil components, phenols, gas components such as H 2 S and NH 3 . Similarly, chemical and industrial processes use water in their operations for cooling, quenching, pH adjustment and washing of various hydrocarbon streams, usually resulting in the creation of an effluent water stream containing inorganic and organic contaminants. Tank farm operations, marine facilities and ships contain effluent water and soil and ground water reservoirs are occasionally contaminated by oil and chemical spills. 
     The Federal Resource Conservation and Recovery Act (RCRA) of 1976 has focused the attention of both industry and government on the problems of land and water way disposal of untreated hazardous waste from industrial facilities, including hydrocarbon processing facilities and oil and gas operating facilities, and encouraged the development of alternative hazardous waste treatment technologies to immobilize and/or destroy the waste either in situ, in previously disposed waste or at the waste generation site. More recent federal legislation, such as the Comprehensive Environmental Response Compensation and Liability Act (CERCLA) of 1980, encourages the development and adoption of hazardous waste treatment and destruction processes that would eventually eliminate the need for land disposal of hazardous waste including water effluent from hydrocarbon processing facilities, except for the disposal residues from treatment operations. Despite the focused attention on the problems, various studies estimate such hazardous waste is generated by the petroleum refining industry at a rate of more than one million tons per year. 
     The biological treatment of waste streams is based on the ability of a mixed population of microorganisms to utilize organic contaminants as nutrients. The two major classes of known biological treatments are aerobic with oxygen and anaerobic without oxygen. Because biological systems contain living organisms, they require specific ratios of carbon and nutrients. Most organisms function within a relatively neutral pH range between 6.0 and 8.0. High concentrations of toxic and organic substances such as cyanide, arsenic, and heavy metal ions and solutions such as copper, lead and zinc inhibit enzyme formation in the microorganisms and eventually kill them. Consequently, some waste streams are not treatable by known biological treatment processes. 
     Wet air oxidation, generally considered to be a pre-treatment process, is used to economically treat aqueous wastes containing both organic and inorganic toxics in waste streams too dilute to incinerate and too toxic to biotreat. The process alters chemical structure by low temperature oxidation of the waste so that toxic compounds become nontoxic. In known wet air oxidation processes, depending on the waste, the off gas may have to be scrubbed or otherwise treated to remove any low molecular weight hydrocarbons present. If an ionic catalyst must be added to the reactor to improve conversion efficiency, a catalyst regenerator must be added to the process. Elevated temperatures ranging from 175-325° C. and residence times ranging from 60-120 minutes are typically required for oxidation of the waste. Most problematic is that process pressure must be maintained between 300-3000 psig to prevent excessive evaporation of liquid. And the typical construction materials appropriate for wet air oxidation reactors are stainless steel, nickel and titanium alloys. 
     Chemical oxidation has been found to be effective in the treatment of certain industrial and domestic wastewater and is one of the few processes for removing odor, color and various potentially toxic organic substances such as phenolics, pesticides and industrial solvents. It also disinfects tranquil water by killing or inactivating pathogenic microorganisms that may be present. The chemical oxidants employed include chlorine, chlorine dioxide, ozone and hydrogen peroxide. Known chemical oxidation processes involve a relatively high operating cost and the chemicals used are consumed in the process. 
     It is, therefore, an object of this invention to provide a process and apparatus useful to treat effluent from hydrocarbon processing facilities. It is also an object of this invention to provide a process and apparatus useful to permit the effluent water discharging from a hydrocarbon processing facility to be recycled or reused. A further object of this invention is to provide a process and apparatus useful to permit the effluent water discharging from a hydrocarbon processing facility to be recycled without treatment at a wastewater disposal plant. Still another object of this invention is to provide a process and apparatus useful to treat effluent from a hydrocarbon processing facility at the facility. Another object of this invention is to provide a process and apparatus useful to treat hazardous wastes that have already entered the water table or landfills. Yet another object of this invention is to provide a process and apparatus useful to immobilize and/or destroy previously disposed waste in situ. An additional object of this invention is to provide a process and apparatus useful to reduce the need for land disposal of hazardous waste other than the disposal residues from treatment operations. It is also an object of this invention to provide a process and apparatus useful to treating a wide range of waste streams. A further object of this invention is to provide a process and apparatus characterized by economically feasible pressure, temperature and residence time requirements in hazardous waste treatment applications. And it is an object of this invention is to provide a process and apparatus characterized by optimized rates of chemical and energy consumption in the treatment of hazardous waste. 
     SUMMARY OF THE INVENTION 
     In accordance with the invention, a process and apparatus are provided for treating effluent water from oil field and industrial facilities with activated media such as porous ceramics so as to reduce residues requiring disposal from treatment operations sufficiently to allow discharge of the effluent water to the sea directly or to recycle the effluent water for other purposes without incurring the disadvantage of generating a solid sludge. 
     The process and apparatus for treating effluent water includes use of a primary separator for removing oil components from the effluent water stream, a secondary separator for removing emulsion type oil components from the effluent water stream and a reactor for absorbing and/or oxidizing organic and/or inorganic impurities such as phenols and BTX and MTBE from the effluent water using the activated media. An air supply device is used to mix the effluent water and activated media. In addition, an agitator may be used to physically mix the effluent water and the activated media in the reaction tank. Sieve trays, structured packing, baffles, or other internals may be used in the configuration of the reactor, depending upon the specific application, the nature and composition of the impurities and desired level of contaminant reduction. 
     In the effluent water treatment process, a stream of effluent water is fed to a reactor filled with porous ceramic media. Organic and inorganic impurities are absorbed from the effluent water into, and/or oxidized by, the porous ceramic media. The remainder of the effluent water stream exits the reactor in an outlet stream. Insoluble oil components may be separated from the effluent water stream prior to feeding the stream to the media filled reactor. Emulsion oil components may also be separated from the effluent water stream prior to feeding the stream to the media filled reactor. The total organic content and the suspended solids content of the feed stream upstream of the reactor may be monitored and the reactor automatically by-passed in response to a determination that either is less than a predetermined standard. The monitored total organic content and the total suspended solids content of the feed stream upstream of the reactor and the reactor feed rate may also be used to automatically calculate the air flow rate and feed stream residence time in the reactor. Flow of the feed stream to the reactor may be automatically terminated in response to a determination that the total organic content or the total suspended solids content of the feed stream upstream of the reactor is greater than a predetermined maximum. The total organic content of the effluent stream downstream of the reactor may be monitored and the effluent stream may be automatically returned to the upstream feed stream in response to determination that the total organic content of the effluent downstream of the reactor is more than a predetermined maximum. 
     The reactor has a chamber which contains pellets of porous ceramic media. A first inlet port receives the effluent water into the chamber. A second inlet port admits an oxidizing agent into the chamber. A first outlet port discharges air and combustion products from the chamber. A second outlet port discharges the remainder of the effluent water from the chamber. The pellets may be stored in vertical stacks of sub chambers defined by horizontal perforated trays, in a horizontal chain of sub chambers defined by at least one vertical perforated baffle or in a combination of vertical and horizontal sub-chambers. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which: 
         FIG. 1  is a block diagram illustrating the process and apparatus for treating effluent water in accordance with the present invention; 
         FIG. 2  is a schematic diagram illustrating the instruments and controls associated with the feed surge of the water treatment system; 
         FIG. 3  is a schematic diagram illustrating the instruments and controls associated with the primary separator of the water treatment system; 
         FIG. 4  is a schematic diagram illustrating the instruments and controls associated with the secondary separator of the water treatment system; 
         FIG. 5  is a schematic diagram illustrating the first of two sets of instruments and controls associated with the reactor of the water treatment system; 
         FIG. 6  is a schematic diagram illustrating the second of two sets of instruments and controls associated with the reactor of the water treatment system; 
         FIG. 7  is a cross-sectional view illustrating an embodiment of the media filled reactor; 
         FIG. 8  is a schematic diagram illustrating embodiments of a by-pass system, a backflush system and an exhaust blower system for use with reactor; 
         FIG. 9  is a schematic diagram illustrating an embodiment of the air flow system of the reactor; 
         FIG. 10  is a schematic diagram illustrating the post-reactor instruments and controls of the water treatment system; and 
         FIG. 11  is a control schematic logic diagram for the water treatment system. 
     
    
    
     While the invention will be described in connection with preferred embodiments thereof, it will be understood that it is not intended to limit the invention to those embodiments or to the details of the construction or arrangement of parts or of the process steps illustrated in the accompanying drawings. 
     DETAILED DESCRIPTION 
     In the description, some flow lines connect system components which are illustrated in different Figures. Such flow lines have been identified by one or more capital letters with a superscripted asterisk and a subscript number. Each letter with superscripted asterisk indicates a particular flow line. The subscript indicates the other Figure associated with the flow line. For example, looking at  FIG. 2 , the identifier H 10 * is used with respect to the flow path from the output of a valve  29 . Turning to  FIG. 10 , as indicated by the subscript in  FIG. 2 , the identifier H 2 * continues the H* flow path to the output of another valve  142 . Conversely, continuing to look at  FIG. 10 , the subscript of the identifier H 2 * indicates that the other end of the flow line H* will be found in  FIG. 2 . 
     The System 
     Turning first to  FIG. 1 , a system for treating effluent water W discharged from oil field and industrial facilities includes a primary separator  30  for removing insoluble oil components and suspended solids I from the effluent water W, a secondary separator  50  for removing emulsion type oil components E from the effluent water W and a reactor  90  filled with porous ceramic media for reacting organic and/or inorganic impurities R such as BTX, phenols, methanol and MTBE from the effluent water W. As hereinafter described, surge tanks, distributors, pumps and recycle lines may be installed between and/or around the primary separator  30 , secondary separator  50  and/or the activated media filled reactor  90  to facilitate operation of the system and to handle process upset conditions at the hydrocarbon processing or oil field facility. However, depending on the application, use of the primary separator  30  and/or the secondary separator  50  and related equipment and steps as hereinafter described may be omitted. 
     The stream of effluent water W discharged from the hydrocarbon processing facility or oil and gas production facility may include insoluble oil components I o  and suspended solids I s  and or emulsion-type oil components E as well as other organic and inorganic impurities R. It may be desirable to remove some or all of the insoluble oil components I o  and suspended solids I s  and/or some or all of the emulsion type components E from the initial stream of effluent water W before removing the impurities R. Insolubles I, in general, are intended to include insoluble oils I o  and insoluble solids I s  Thus, the total stream of effluent water W may be fed to the activated media filled reactor  90  and its associated components, or the total stream of effluent water W less all or some of either or both the insolubles I and emulsions E, that is W−I, W−E or W−I−E, might be fed to the activated media filled reactor  90  and its associated components. 
     It should not be inferred that the primary separator  30  or the secondary separator  50  must remove all the insolubles I and emulsions E from the initial stream of effluent water W. Nor should it be inferred that the function of the primary separator  30  or the secondary separator  50  must be performed, if at all, by a single primary separator  30  or a single secondary separator  50 . The efficiency of the reactor  90  is adversely impacted by the impurities content of the input W−I−E to the reactor  90 . It is, therefore, desirable to monitor and control the operation of any primary and secondary separators  30  and  50  in the system and, in extreme conditions, to shut down the operation of the reactor  90  until the W−I−E meets acceptable standards. 
     Continuing to look at  FIG. 1 , the equipment in the input stream of effluent water W to the primary separator  30  may include a feed surge tank  10  and a distributor  20 . The feed surge tank  10  serves to average the flow of effluent water through the system of separators and reactors and the distributor  20  serves to monitor, control and stabilize the flow of effluent water through the system of separators and reactors. Once fed into the feed surge tank  10 , the insoluble oil components I o , having a low specific gravity, migrate to the upper portion of the feed surge tank  10  and are discharged to a slop oil tank (not shown) residing in the user&#39;s facility. These components I o  may be reprocessed by the operator of the oil field or hydrocarbon processing facility. As is well known, the efficiency of the separation in the feed surge tank  10  can be enhanced by the installation of filters, inclined plates or baffles in and/or the application of heat to the feed surge tank  10 . The remaining water component W−I o , having a high specific gravity, remains in the lower portion of the feed surge tank  10  and is caused to flow under level control to the primary separator  30  by use of pumps as required. 
     The effluent water less the removed solids W−I exits the primary separator  30  and is fed to the secondary separator  50  through a distributor  40 . The distributor  40  monitors, controls and stabilizes the flow. In the secondary separator  50 , the effluent water W−I is optimally mixed with naphtha, air, natural gas or other agent to remove the emulsion type oil components E. The removed components E are collected in a waste tank  51  for sale, recycling or use as fuel in heaters or electro-generators. 
     The effluent water W−I−E discharged from the secondary separator  50  is passed through a reactor feed tank distributor  60 , a reactor feed tank  70  and a reactor distributor  80  which are serially installed between the secondary separator  50  and the activated media reactor  90  to prevent the effluent water W−I−E from flowing into the activated media reactor  90  in case of failure by the secondary separator  50  to properly prepare its discharge W−I−E for feeding into the reactor  90 , thus protecting the integrity of the activated media. In the reactor  90 , other impurities R are removed, resulting in the desired effluent product W−I−E−R. 
     The distributors  60  and  80  include the instruments and controls associated with the reactor feed tank  70  and the reactor  90 . The system may also include a bypass system  110 , a backwash system  120  and/or a post-reactor distributor  140  to further protect the reactor  90 . 
     In the following description of the components of the system, logic related primarily to the component described is included in the Figure associated with the component. Logic related to multiple components is further integrated into  FIG. 11 . 
     The Primary Separator Feed Surge Tank  10   
     Looking at  FIGS. 1 and 2 , the feed surge tank  10  has a low-low level indicator  11  which uses logic L- 21  to shut down the feed pump  21 , seen in  FIG. 2 , if the level of the tank  10  is low enough to jeopardize the integrity of the feed pump  21 , as would occur if the feed pump  21  were allowed to run dry. The feed surge tank  10  also has low level  12  and high level  14  indicators which serve as alarms to alert the user of abnormal conditions. The feed surge tank  10  also has a high-high level indicator  13  which sends a signal to the user&#39;s process control system to indicate that the water treatment process module cannot take more feed for the moment. Waste water flows under the tank overflow baffle. Undissolved oil and organic material I o  float on top of the water and are drained off to the slop oil tank in the user&#39;s facility. Some solid material suspended in the plant waste water which enters the feed surge tank  10  may sink to the bottom of the tank  10 . A sludge drain permits periodic removal of the collected solids. 
     The water to be treated in the primary separator  30  flows under the underflow baffle of the feed surge tank  10  to the feed pump  21 . The feed surge tank level is controlled by a level controller  22  and a flow valve  23 . The temperature of the water exiting the surge tank  10  is measured with a temperature transmitter  24 . The level controller  22  is cascaded to a primary flow controller  25  to measure the flow rate of the water exiting the surge tank  10 . Where practical, it is preferable to eliminate level controller  22  and have the flow controller  25  retain a user-entered set-point to fix the feed-flow at the maximum rate the module can accept and let the user&#39;s process maintain the level of feed surge tank  10 . This would maintain a more constant flow through the water treatment module. 
     The Primary Separator Distributor  20   
     The primary separator distributor  20 , illustrated in greater detail in  FIG. 2 , includes the instruments and controls associated with the primary separator  30 , hereafter described in  FIG. 3 . 
     The feed pump  21  supplies the motive force for the effluent stream from the tank  10 . Its continued operation is subject to certain conditions and shutdowns hereinafter described. As seen in  FIGS. 2 and 11 , the feed pump  21  preferably has a control-panel-located emergency shutdown button L- 21   a , a field-located emergency shut-down button L- 21   c , and an automatic shutdown controlled by the feed pump logic L- 21 . Preferably, when the feed pump  21  is shut down by its logic L- 21 , a reset button L- 21   b  must be pressed before it can be re-started. This allows the user time to investigate the cause of the shutdown and avoids sudden re-starts before causation is established. At the outlet of the feed surge tank  10 , a fast-acting analyzer  26  measures the total organic carbon content of the feed stream. An associated indicator L- 26  sends a signal to bypass logic L- 29  which will bypass the feed stream around the water treatment module whenever the feed stream is clean enough to not need treatment. This is accomplished by opening the bypass valve  29  shown in  FIG. 2  and closing the primary separator valves  32   a  and  33   a  seen in  FIG. 3 , shutting down the reactor feed pump  83  seen in  FIG. 6  and the treated water transfer pump  143  seen in  FIG. 10 , and shutting the secondary separator outlet valve  62  seen in  FIG. 5 . This prevents unnecessary processing of acceptable water and extends the life of the module. The concentration of organics in the water exiting the tank  10 , as measured by the organic content analyzer  26  and the feed rate  25  are used to calculate the air flow rate and residence time required for desired dissolved organic reaction in the reactor  90 . As previously described, if the concentration of organics in the water exiting the tank  10  meets the requirements of the treated water supply stream  28 , the water is directed to the treated water supply stream  28  without further treating by means of a bypass solenoid valve  29 . If the concentration of organics in the water exiting the tank  10  does not meet the requirements of the treated water supply stream  28 , the water is directed to the primary separator  30 . At the outlet of the feed surge tank  10 , the analyzer  27  measures the total suspended solids in the feed stream. When feed stream solids exceed a trigger point, an associated indicator L- 27  sends a signal to the pump logic L- 21  to shut down the feed pump  21  in order not to overwhelm the process with a feed that would plug the inlet filters quickly. An alarm is also sent to the user&#39;s process control system indicating that the stream has too many solids to process through the water treatment module. 
     The Primary Separator  30   
     Looking at  FIG. 3 , the effluent water less the skimmed hydrocarbons enters the primary separator  30 , which may consist of a set of in-line parallel filters  32  and  33 . The purpose of the primary separator  30  is to remove solids and/or sediment in the feed stream which, above a pre-specified limit, could damage reactor components and cause undesirable opacity in the product stream. 
     The filters  32  and  33  normally operate with one filter in-line with the feed stream and one held in readiness after undergoing a backwash cycle. A switch of filters and subsequent backwashing of the newly off-line filter is triggered by the in-line filter pressure drop reaching a pre-determined threshold. The backwash logic module L- 30  coordinates the flushing of solids from the selected filter via eight valves  32   a, b, c, d  and  33   a, b, c, d  into a receiver tank  31 . The tank  31 , via a valve  31   a , dumps a solid-laden clean effluent periodically to maintain its level between predetermined values. The pressure drop across the filters  32  and  33  is measured by gauges  34  and  35 , respectively, and if the pressure drop on either of the filters  32  or  33  reaches a trigger value, associated alarms L- 34  and L- 35  will send a signal to the filter backwash logic L- 30  which then isolates and performs backwash operations on the appropriate filter  32  or  33  and sets it in a “ready” status for the next high-high filter pressure drop condition. At any given time, the backwash logic L- 30  is responsible for the position of the inlet valves  32   a  and  33   a , except when the bypass logic block L- 29  is holding the filter inlet valves  32   a  and  33   a  closed. Backwash of the filters  32  or  33  is performed by opening either one pair of solenoid valves  33   c  and  33   d  for one filter  33  or another pair of solenoid valves  32   c  and  32   d  for the other filter  32 . A slop oil tank  31  receives the backwash from the filters  32  and  33 . As the contents of this tank  31  are high in solids, a ball valve  31   a  is opened whenever the indicator L- 39  associated with a level controller  39  sends a high-high signal to the dump logic L- 31 . This allows the sediment-laden effluent to “blow through” the ball valve  31   a  instead of plugging it. 
     The Secondary Separator Distributor  40   
     The secondary separator distributor  40 , illustrated in greater detail in  FIG. 4 , includes the instruments and controls associated with the secondary separator  50 . The concentration of total suspended solids in the water exiting the primary separator  30  is measured with a total suspended solids analyzer  41  before being passed to a venturi tube  42 . The analyzer  41  is located just downstream of the separator  30 . When a total suspended solids trigger value is reached, its associated indicator L- 41  sends a signal to the feed pump logic L- 21 , seen in  FIGS. 2 and 11 , which will shut down the feed pump  21  in order not to send solids to the downstream reactor  90 , whose activated media  91  would be deactivated or plugged by the solids. The air to the venturi  42  is regulated by ratio control through flow valves  43  and  44 . Flow controllers  45  and  46  receive remote set-points from a ratio controller  47  which holds the total air going into the venturi  42  at a constant ratio with the process feed rate at the flow controller  25  in the primary separator distributor  20  as seen in  FIG. 2 . The ratio calculation logic L- 40  calculates the sum of flows measured by the flow controllers  45  and  46  for use as the air input measurement of the ratio controller  47 , calculates the ratio of air to feed for the ratio controller  47 , splits the output of the ratio controller  47  equally to the flow controllers  45  and  46  and calculates the ratio of reactor air to feed for the feed/reactor air ratio logic L- 120  as seen in  FIG. 9 . As shown, the user enters the ratio set-point directly into the controller  47 . However, it is likely that this will become a remote set-point if the ratio has a direct effect on the total organic content measured by an analyzer  61  in the secondary separator effluent as hereinafter seen in  FIG. 5 . The well-mixed water and air enters the secondary separator  50 , which is envisioned as a floatation cell, hydroclone or similar device. 
     The Secondary Separator  50   
     In the likelihood that the secondary separator  50  contains an upper layer of hydrocarbon emulsion under normal operation, it is desirable not to allow this emulsion to drain down into the reactor feed surge tank  70 , seen in  FIG. 1 , and subsequently contaminate the activated media in the reactor  90 . Therefore, the secondary separator  50  works in conjunction with an emulsion waste tank  51 . The emulsion layer normally will overflow into the emulsion waste tank  51 . The level of the emulsion waste tank  51  is monitored by a level indicator  54 . One indicator L- 54   a  sends an alarm to the operator when the level reaches a preset high value and another indicator L- 54   b , seen in  FIG. 11 , sends a shutdown signal to the feed pump logic L- 21  at a preset trigger high-high level to prevent overflow of this material into the reactor vent system, which is boosted by an exhaust blower  53 , as seen in  FIG. 1 . A manual drain valve  52  may be opened periodically by the user to drain the emulsion waste tank  51 . This loop can be automated. 
     The Reactor Feed Tank Distributor  60   
     When flow stops to the secondary separator  50  for any reason, the emulsion layer will flow by gravity into the reactor feed tank  70  unless the drain valve  62  from the secondary separator  50  is closed. As seen in  FIGS. 5 and 11 , anti-drain-down logic L- 60  of the feed surge tank distributor  60  monitors all conditions which may result in a drain-down of the secondary separator  50 . This includes all conditions in which the feed pump  21  has been shut down, among others. The emulsion exits the secondary separator  50  and is collected in the emulsion waste tank  51 , as seen in  FIG. 1 . Air and vapors are directed to a vent or a flare or ingested in a gas engine or fired heater. The water W−I−E exits the secondary separator  50  and the total organic content of the water is measured with a total organic content analyzer  61 , as seen in  FIG. 5 . If the total organic content of the water W−I−E exceeds a predetermined set point, typically 1,000 parts per million, the solenoid valve  62  immediately closes, to prevent drain-down and to protect the reactor  90  from fouling. The exact value varies according to the demands of the specific application. The bottoms outlet temperature of the secondary separator  50  is measured by a temperature transmitter  63  and this information is used to optimize the control of the reactor  90 . The water W−I−E is directed from the distributor  60  to the reactor feed tank  70 . 
     The Reactor Distributor  80   
     The distributor  80  to the reactor  90  is illustrated in greater detail in  FIG. 6 . The reactor feed tank  70  receives the bottoms effluent from the secondary separator  50  and serves as the feed surge tank for the reactor  90 . Its bottoms level controller  81  controls the effluent rate from the feed tank  70  which is the feed to the reactor  90 . As seen in  FIG. 11 , the feed tank  70  has a low-low indicator L- 70   a  which works with the reactor feed pump logic L- 83  to shut down the reactor feed pump  83  if the level of the reactor feed tank  70  is low enough to jeopardize the integrity of the feed pump  83  which would occur if the pump  83  were allowed to run dry. Looking at  FIG. 1 , the reactor feed tank  70  also has low level and high level indicators L- 70   b  and L- 70   c , respectively, which serve as alarms to alert the user to abnormal conditions. Returning to  FIG. 11 , the reactor feed tank  70  has a high-high level indicator L- 70   d  which sends a signal to the primary separator feed pump logic L- 21  shown in  FIG. 2  to shut down the primary separator feed pump  21  and also sends a message to the user&#39;s process control system that the water treatment process module cannot take more feed for the moment. As seen in  FIG. 6 , the reactor feed pump  83  supplies the motive force for the demulsified water from the reactor feed tank  70  which supplies both reactor feed  85  and backwash source  86  streams. Its continued operation is subject to certain conditions and shutdowns described above. The reactor feed pump  83  has a control-panel-located emergency shut-down button L- 83   a , a field-located emergency shut-down button L- 83   c  and an automatic shut-down controlled by the feed pump logic L- 83 . When the reactor feed pump  83  is shut down by its logic L- 83 , a reset button L- 83   b  must be pressed before it can be restarted. This allows the user time to investigate the cause of the shutdown and avoids sudden restarts before causation is established. 
     Looking at  FIGS. 6-8 , a pressure transmitter  84  measures the pressure in the distribution nozzles  102  of the reactor  90 . This pressure is a function of the flow rate out of the reactor feed tank  70 , which is controlled by the level controller  81 , the pressure boost supplied by the reactor feed pump  83  and the number of nozzles  102  open to the reactor inlet flow. The control system allows input of a minimum acceptable pressure L- 80   a  and opens or closes successive banks of nozzles  102  to maintain this value. This is accomplished by the user setting a minimum pressure L- 80   a  as a set-point to the distributor pressure control logic L- 80 . The logic L- 80  will open more nozzles  102  using solenoid valves  112  as long as the pressure remains at or above the minimum pressure set-point. As the pressure at the pressure transmitter  84  starts to drop below the minimum pressure, banks of nozzles  102  are closed successively until the pressure stabilizes once again at or above the minimum pressure. To prevent excessive cycling of the valves  112 , small dead-bands are integrated into the controller. Associated distributor logic allows the system to operate in manual mode so that the user can have individual access to each of the valves  112  if necessary. 
     The Reactor  90   
     Looking at  FIG. 7 , an embodiment of the porous ceramic media reactor  90  is illustrated. The activated media  91  in the reaction tank  92  of the reactor  90  reacts with the effluent water W−I−E, particularly with the remaining organic and/or inorganic impurities R such as phenols, BTX, methanol and MTBE in the reactor  90 . The activated media  91  used in the present invention has a particle size of 0.5 to 4 centimeters and is preferably introduced into the reaction tank  92  of the reactor  90  in pellet form. An air supply system, hereinafter described, mixes the effluent water W−I−E with the porous ceramic media  91  by injecting air into the reaction tank  92  through an air inlet  93  to a header  94  with an array of air distribution nozzles  95  at the bottom of the reaction tank  92 . The nozzles  95  upwardly disperse the air uniformly throughout the reaction tank  92 . An agitator  96  may optionally be included in the reactor  90  to assist in mixing the effluent water W−I−E with the porous ceramic media  91  in the reaction tank  92 . The agitator  96  rotates above the array of nozzles  95  on a shaft  97 , preferably driven by an electric motor  98  typically in a range of up to approximately 180 rpm. The effluent water W−I−E is introduced via a water inlet  99  to a distribution header  101  and an array of water distribution nozzles  102  at the top of the reaction tank  92 . The nozzles  102  downwardly dispense the water uniformly across the area of the reaction tank  92 . The media  91  is contained in compartments  103  in the reaction tank  92 . The compartments  103  are formed by upper and lower horizontal perforated plates  104  and  105  spaced along the height of the reaction tank  92  and vertical perforated baffles  106  spaced between pairs of the horizontal plates  104  and  105 . The pairs of upper and lower horizontal plates  104  and  105  form trays of media  91  spaced apart in the tank  92 . The compartments  103  insure uniform distribution of the media  91  in the tank  92  and reduce the likelihood of migration of the media  91  in the tank  92  as the media  91  disintegrates into finer pieces. The treated water exits the reaction tank  92  through an outlet  107  at the bottom of the tank  92  and the gaseous waste exits the tank  92  through an outlet  108  at the top of the tank  92 . 
     The tank  92 , plates  104  and  105  and baffles  106  may be of any suitable material including galvanized steel, stainless steel, aluminum, plastic or steel. However, plastics may not be suitable for some organic materials and steel may deteriorate. The perforations are preferably punched or drilled holes of diameter suitable to retain the porous ceramic media  91  evenly distributed in the plates  104  and  105  and baffles  106 . The agitator  96  is preferably stainless steel. The tank  92  may be rectangular or cylindrical, the former being preferred for ease of manufacture. The residence time of the water W−I−E in the reactor tank  92  is preferably about 30 minutes, but can vary from 5 minutes to 24 hours, depending upon the application. Multiple reactors installed in series or parallel may be required in certain applications. 
     Bypass and Backwash Systems  110  and  120   
     Turning now to  FIG. 8 , the reactor  90  may be equipped with a bypass system  110  and/or backwash system  120 . In the by-pass system  110 , multiple inlet water headers  111  are each controlled by a separate solenoid valve  112  to introduce flow W−I−E between selected beds of media  91  formed by the upper and lower plates  104  and  105 . Thus, beds fouled by oil or debris can be by-passed. In the backwash system  120 , the reactor water outlet  107  has a block valve  121  with a T-joint  122  connecting the clean water from the reactor  90  to multiple clean water headers  123  each controlled by a separate solenoid valve  124 . This permits introduction of clean water or a cleaning solution into the reactor  90  to clean selected individual beds of media. As also seen in  FIG. 8 , the reactor  90  may be optionally equipped with an exhaust blower  125  for those applications where the vent system has a high pressure drop. The reactor  90  is also equipped with a combination pressure and vacuum safety valve  126  which protects the reactor  90  from over or under pressure. As seen in  FIG. 8 , the sludge drain block valve  132  in the reactor  90  facilitates the removal of sludge and media fines. The bottom of the reactor  90  is sloped toward a low point drain outlet connection  137 . 
     External Reactor Air Injector System  130   
     Looking at  FIG. 9 , one of several possible ways to direct air into the reactor  90  is illustrated. A positive displacement blower  127 , optionally equipped with a motor with variable frequency drive to control air flow rate if required, forces air into an external air header  128  relative to the reactor  90  and through multiple rotameters  129 , which continuously monitor the air flow rate into the reactor  90 . As an alternative to the rotameters  129 , orifice plates having pre-specified diameters sized to equalize pressure and therefore airflow into the individual chambers may be used. As shown, the reactor  90  is divided into vertical cells  109  consisting of stacks of beds of media contained in compartments  103  as seen in  FIG. 7 . A pressure transmitter  131  and a local blowoff valve  132  are used to prevent over-pressuring the inlet air header  128  or the rotameters  129 . As shown, the flow to the rotameters  129  may be controlled by separate solenoid valves  133  so as to most efficiently use the cells  109 . 
     The Post-Reactor Distributor  140   
     The distributor  140  consisting of the post-reactor instrumentation and controls is illustrated in greater detail in  FIG. 10 . The water level in the reactor  90  is maintained by a level controller  141  and a level control valve  142 . A treated water transfer pump  143  draws suction from the bottom of the reactor  90 . The temperature is monitored with a temperature transmitter  144  and the total organic content is monitored with a total organic content analyzer  145 . If the total organic content of the water pumped out of the reactor  90  fails to meet the requirements of the treated water system, a flow valve  146  is opened to direct the flow to the reactor feed tank  70 . The recycle flow rate to the reactor feed tank  70  is continuously monitored by a flow transmitter  147 . For long-term, substantial recycle flows, a feedback loop to the process inlet will be implemented to reduce feed to the system. 
     Protective Logic of the System 
     Turning now to  FIG. 11 , the field instrumentation, connective wiring, control valves, computer, distributed control system DCS and human-machine interface HMI, collectively hereinafter referred to as the control system, for automatically controlling, safeguarding and monitoring the water treatment process using instrumentation and computer-driven electronics is illustrated. The control system monitors the purity of the inlet stream and modifies process conditions and flows online so that the outlet stream meets required treated effluent specifications. The DCS interfaces the field instrumentation with a database upon which various control algorithms are applied. This database also interfaces with the HMI so that operators can monitor operations, change setpoints, maintain the equipment, and initiate manual shutdowns at their discretion. The HMI consists of a keyboard and video monitor attached to the DCS computer. It features a graphical representation of the process and graphical icons which serve as monitors and controllers for the various process parameters. A physical control panel adjacent to the DCS and HMI has manual override switches for various control requirements. 
     As described in relation to  FIGS. 1-10 , the process is modular and very flexible, facilitating operation on a wide range of feed qualities and quantities. The process and apparatus illustrated in  FIG. 11  represents an operational scenario highlighting the functionality of the automated control system. 
     The reactor  90  receives the bottoms effluent from the reactor feed tank  70 . The final reaction occurs in the reactor  90  through a combination of the correct conditions and residence time. As seen in  FIG. 10 , the bottoms level controller  141  controls the net effluent rate from the reactor  90 , which is the process module product. The temperature transmitter  144  measures the temperature of the direct reactor effluent. A low-low level indicator L- 90   a  works with the logic L- 143  of the treated water transfer pump  143  to shut down the transfer pump  143  if the tank level of the reactor  90  is low enough to jeopardize the integrity of the transfer pump  143 , which would occur if the pump  143  were allowed to run dry. Low level and high level indicators L- 90   c  and L- 90   d , respectively, serve as alarms to alert the user to abnormal conditions. A high-high level indicator L- 90   b  sends a signal to the reactor feed pump logic L- 143  to shut down the recycle flow valve  146  and also sends a message to the user&#39;s process control system that the water treatment process module cannot take more feed for the moment. The transfer pump  143  supplies the motive force for the effluent from the reactor  90 , which comprises both the net reactor treated effluent and the recycle stream. Its continued operation is subject to certain conditions and shutdowns described above. The transfer pump  143  has a control-panel-located emergency shutdown button L- 143   a , a field-located emergency shut-down button L- 143   c  and an automatic shutdown controlled by the feed pump logic L- 143 . When the transfer pump  143  is shut down by its logic L- 143 , a reset button L- 143   b  must be pressed before it can be restarted. This allows the user time to investigate the cause of the shut-down and avoids sudden re-starts before causation is established. 
     Looking at  FIG. 9 , the positive displacement blower  127  introduces air as an oxidant to the reactor beds. The reactor  90  is the tertiary and final separation section of the module. A flow controller  134  receives an air flow signal from a flow transmitter  136  and remote set-point from ratio controller  135  which holds the total air going into the reactor  90  at a constant ratio with the process feed rate measured by the flow controller  25  seen in  FIG. 2 . The ratio calculation logic L- 120 , seen in  FIG. 9 , calculates the ratio of reactor air to feed for the feed/reactor air ratio controller  135 . While the user may enter the ratio set-point directly into the controller  135 , this can be remotely set if it can be determined that the ratio has a direct effect on the total organic content reading of the analyzer  145  on the direct effluent from the reactor  90 , as seen in  FIG. 10 . The pressure of the air to the reactor beds is measured by the pressure transmitter  131 . Fixed orifices may be used rather than flow valves in order to automatically flow-balance the system and the air nozzle banks may be constructed to correspond to the reactor feed nozzle banks and be shut down in parallel with the same minimum pressure nozzle bank outputs of the reactor feed pressure controller L- 80 . 
     Returning to  FIG. 10 , the reactor treated effluent recycle loop is controlled by the flow controller  147  which receives a cascaded remote set-point from the total organic content analyzer/controller  145  for the treated effluent. Should the total organic content of the reactor treated effluent exceed the maximum acceptable value, the controller  145  will attempt to bring the value down by recycling reactor effluent to the reactor feed tank  70 . It is expected that the additional reaction exposure and residence time will reduce the total organic content to specified levels. Should the recycle prove excessive, such that the level in the reactor  90  cannot be controlled, a signal is sent to the user&#39;s process control system indicating that the water treatment module cannot continue successful operation at the current feed rate. Alternatively, if the system front end is being operated on a flow basis rather than level control basis, this same signal would instead be sent to alert the user that the feed rate needs to be lowered, or that process problems are arising. The signal can also be used in a constraint control configuration where the feed flow rate is manipulated gradually to the point that the net reactor effluent is just meeting minimum product standards. This would automatically optimize throughput while maintaining operability. 
     In summary of the system logic, if one or both of the total organic content and total suspended solids are too high to process, inlet flow to the reactor is terminated. If both are very low and meet effluent specifications, the treatment process is bypassed. If the total suspended solids are creating high filter dP, a warning is sounded to initiate a backwash and filter swap. If the total suspended solids after filtration are high, flow to the system is terminated to avoid plugging. The total organic content at the reactor inlet is measured for calculations which determine the optimum amount of air to inject at the bottom of the reactor. The total organic content at the reactor outlet is measured for monitoring purposes only. If the total organic content measured at the reactor outlet is slightly high, a warning that the reactor is not working properly should be sounded. If it is very high reactor effluent can be recycled back to the reactor feed tank. 
     The Process 
     Thus, looking again at  FIG. 1 , the process of treating effluent water W from a hydrocarbon processing facility comprises the steps of removing free oil components I o  from the effluent water W in feed surge/settling tank  10 , filtering solids I s  out in a primary separator  30 , removing emulsion type oil components E using naphtha or natural gas or air in a secondary separator  50  and reacting the remaining effluent stream with porous ceramic media in the reaction tank  92  of the reactor  90  to remove organic and/or inorganic impurities R such as phenols and other hydrocarbons. The process also utilizes supplemental equipment, instrumentation and controls such as described in relation to the various tanks  10 ,  31 ,  51  and  70  and distributors  20 ,  40 ,  60 ,  80  and  140  to monitor, control and, if necessary, bypass or terminate flow of water to be treated by the separators  30  and  50  and the reactor  90 , as well as flow of other materials to facilitate efficient operation of the system and particularly the reactor  90 . 
     It is, therefore, apparent that there has been provided, in accordance with the invention, a process and apparatus for treatment of effluent water that fully satisfies the objects, aims and advantages set forth above. While the invention has been described in conjunction with specific embodiments thereof, it will be evident that many alternatives, modifications and variations will be apparent to those skilled in the art and in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit of the appended claims.