Abstract:
An apparatus for reclaiming hot process water from a animal processing facility includes a screen portion, a filtration portion and optionally a UV sterilization portion. The screen portion receives dirty hot process water and removes macroscopic debris to produce raw tank water. Raw tank water is pumped through the filtration portion at relatively high pressure in order to remove substantially all solids to produce a permeate side stream. The permeate is optionally passed through a very intense ultra-violet field in order to produce uncontaminated reclaimed hot process water which may be safely reintroduced as hot scald water for the poultry cleaning process.

Description:
FIELD OF THE INVENTION 
     This application claims the benefit of provisional U.S. patent application Ser. No. 61/200,175 filed on Nov. 25, 2008 which is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to an apparatus and method for cleaning and reclaiming contaminated water from an animal processing facility. 
     BACKGROUND OF THE INVENTION 
     Hot water or “scald water” is used in poultry processing facilities to remove feathers and to clean poultry in an initial stage of poultry processing. Typically, an overflow of wastewater from such a process is highly contaminated and is discharged to a Dissolved Air Flotation System (DAF) and then further released to a municipal wastewater treatment facility. In so doing, the water is lost and the energy input to heat the process water is lost, resulting in significant water costs, discharge costs, treatment costs and energy costs for the facility. What is needed is a means for cleaning and reclaiming process water in order to reclaim most of the heat invested in the process water and much of the water itself in order to reduce energy and resource costs. 
     BRIEF DESCRIPTION 
     The above-described need is addressed by an apparatus for reclaiming hot process water from an animal processing facility. The apparatus includes a screening and settling portion, a filtration portion and may optionally include a UV sterilization portion. The screening and settling portion receives raw process water and removes macroscopic debris to produce tank water. Tank water is pumped through the filtration portion at relatively high pressure in order to remove substantially all solids to produce a permeate. The filtration portion features ceramic filter units which each have a multitude of small diameter channels extending between a filter unit inlet and a filter unit discharge. Most of the tank water flows from the inlet to the discharge of the filter unit while only some of the tank water is filtered as it permeates the walls of the channels and is collected as permeate. The unfiltered tank water collected at the discharge is recycled back through the filtration portion. The permeate collected from the filter units and may be passed through a very intense ultra-violet field in order to produce uncontaminated reclaimed hot process water which may be safely re-introduced as hot process water for the poultry cleaning process. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of the hot water recovery apparatus of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     As noted above, the initial stages of poultry processing employs a continuous flow of hot (i.e. generally between 120 to 160 degree F. and preferably 140 degree F) water. This hot water is known as “scald water” in a poultry processing facility and is used to clean poultry carcasses and becomes heavily contaminated with animal waste by-products, including feathers, blood, high concentrations of numerous types of pathogens and other biological waste during the initial carcass cleaning process. Hereinafter, “scald water” will be referred to with the more general term of “process water”. As noted above, the prior art process has been to release this highly contaminated hot process water into a waste water treatment process where the heat energy invested in the process water and the water itself is lost. The purpose of process water cleaning apparatus  10  is to clean and reclaim this hot process water while retaining the previously invested heat energy. Preferably, process water cleaning apparatus  10  is contained in a transportable unit which can be turn key installed at a animal processing facility. Preferably, process water cleaning apparatus  10  is self contained and includes a control unit which may communicate via the interne so that a remote technician can monitor its operation as will be described in greater detail below. 
     Referring to the drawings,  FIG. 1  provides a schematic diagram of the process water cleaning apparatus  10  of the present invention. The apparatus generally includes, a screening and settling portion  20 , a ceramic filter portion  100 , an ultra-violet sterilization portion  300  and a control module  500 . It is preferable that process water cleaning apparatus  10  be skid mounted in an envelope which is transportable in a trailer of a type such as a standard over the road tractor-trailer unit. Also preferably, control module  500  is accessible via the interne so that monitoring and control of process water cleaning apparatus  10  may be conducted at a remote location. Accordingly, process water cleaning apparatus  10  can be built, transported and then integrated into an existing poultry processing facility often by placement of the unit on the roof of a poultry processing facility and monitored and operated from a remote location. 
     Hot dirty process water is received from a poultry carcass cleaning process and pumped to screening and settling portion  20  which includes a screen drum unit  22  and a settling tank  28 . In this example, screen drum unit  22  includes a cylindrical screen  22 A having mesh size of approximately 100 microns and preferably a mesh size generally between 50 and 150 microns. The effluent from rotating screen drum unit  22  may be identified as screened process water. The screened process water is conveyed to settling tank  28 . Solid materials precipitate out of the screened process water entering settling tank  28  and settle to the bottom of settling tank  28  and are periodically discharged through sediment discharge valve  28 B 1 . Accordingly, the effluent of settling tank  28  does not have the same make up as the screened process water leaving rotating screen drum unit  22  and thus will be referred to below as tank water. Settling tank  28  is connected to a supply of steam  28 S which is introduced into settling tank  28  in order to maintain the temperature of tank water in tank  28  preferably between 130 degrees F. and 150 degrees F. and preferably as close to 140 degrees F. as possible. The applicants have found 140 degrees F. to be the optimum temperature for conducting the cleaning process. A temperature sensor  28 T is connected to a control valve  28 V which releases steam into tank  28  as needed to maintain the desired temperature in tank  28 . Tank water from settling tank  28  is supplied to ceramic filter portion  100  by supply pump  29 . 
     The next portion of process water cleaning apparatus  10  is a filter portion  100 . The flow of tank water into filter portion  100  is powered by supply pump  29 , controlled by control valve  101  and measured by a first flow transmitter  102 . Supply pump  29 , control valve  101  and flow transmitter  102  communicate with control unit  500 . Filter portion  100 , in this example, also includes a re-circulation pump  110  and a set of ceramic filter units  120 A,  120 B and  120 C. 
     Each filter unit consists generally of a pattern of ceramic walled channels extending from a tank water intake to a tank water discharge. These channels are of small diameter typically on the order of 1.5 millimeters in diameter. In this example, in the context of cleaning process water in a poultry processing environment, filter units  120 A,  120 B and  120 C, preferably have a pore size of 0.2 microns but may have another pore size depending on the application. The applicants have found a pore size of 0.2 microns is an optimal choice when compared to other available ceramic filters having other pore sizes. The applicant&#39;s experience is that pores of 0.2 microns, in the context of this example, produce the most permeate with the best run times between purges. Ceramic filter unit  120 A includes a tank water intake  122 A and a tank water discharge  124 A. Accordingly, ceramic filter units  120 B and  120 C also have tank water intakes  122 B and  122 C and tank water discharges  124 B and  124 C respectively. Ceramic filter units  120 A,  120 B and  120 C are arranged in series so that tank water discharge  124 A communicates with tank water intake  122 B and so on. Tank water discharge  124 C communicates with recycle pump  110 . The flow rate of tank water discharged at discharge  124 C is measured by flow meter  128 . Ceramic filter units  120 A,  120 B and  120 C also have permeate discharges  126 A,  126 B and  126 C respectively. 
     As noted above the channels of the ceramic filters of each filter unit have a small diameter on the order of 1.5 millimeters. Most of the flow of tank water through each filter unit merely passes from the tank water intake to tank water discharge through the interiors of the longitudinal ceramic walled channels. On the other side of the porous walls of the ceramic channels of the filter units are spaces which communicate with the permeate discharge of each filter unit. The walls of the ceramic channels are fashioned from ceramic membrane material having fine pores which in this example, as noted above, have a nominal opening size of generally 0.2 microns. 
     By way of example, 350 gallons per minute of tank water may be fed into first ceramic filter unit  120 A while approximately 20 gallons per minute of finely filtered permeate may discharge through permeate discharge  126 A of ceramic filter unit  120 A. Therefore, in this example, approximately 330 gallons of tank water per minute would flow into second ceramic filter unit  120 B. Again, by way of example, in filter unit  120 B, 20 gallons per minute of permeate might also discharge from that unit and so on until approximately 290 gallons per minute of tank water leaves third ceramic filter unit  120 C as another 20 gallons per minute of permeate leaves third ceramic filter unit  120 C. Accordingly, in this example, the amount of tank water which would need to be supplied by supply pump  29 , to make up for the flow of permeate from the three filter units, would be 60 gallons per minute. Still further, the expected pressure drop between the tank water intake and the tank water discharge of each filter unit is expected to be about 20 PSI. The pressure drop between the tank water intake and the tank water discharge will increase above an acceptable limit when the walls of the small diameter ceramic filter channels are obstructed with filtrate material. This pressure drop increase is one indicator that a purge cycle is needed. Also in this example, another indicator that a purge cycle is needed occurs when the flow of permeate out of a filter unit falls substantially below 20 gallons per minute. 
     The performance of ceramic filter units  120 A,  120 B and  120 C is continuously monitored by an array of flow meters and pressure sensors which are in communication with control unit  500 . The flow meters, pressure sensors, pumps and valves described and shown herein are all preferably in communication with control unit  500  either by signal carrying wires or wirelessly. Preferably control unit  500  is linked to the internet so that a remote technician may access control unit  500  via the internet in a web page format and view the parameters relating to the performance of the system. 
     Permeate discharge flow meters  128 A,  128 B and  128 C are located at the permeate discharges  126 A,  126 B and  126 C of ceramic filter units  120 A,  120 B and  120 C respectively. Pressure sensor  122 APS is located upstream of the intake of filter unit  120 A. Pressure sensor  122 BPS is located between filter units  120 A and  120 B. Pressure sensor  122 CPS is located between filter units  120 B and  120 C. And, pressure sensor  124 CPS is located downstream of the discharge of filter unit  120 C. The data taken from permeate discharge flow meters  128 A,  128 B and  128 C and pressure sensors  122 APS,  122 BPS and  124 CPS are used to monitor the performance of the filter units as will be described in greater detail below. 
     The finely filtered permeate leaving permeate discharges  126 A,  126 B and  126 C is conveyed to purge tank  202 . The permeate flow from each of these filter units  120 A,  120 B and  120 C is an intermediate product of this process. The permeate flow is very finely filtered and continues to retain the relatively high temperature of the initial tank water stream. Downstream of permeate discharges  126 A,  126 B and  126 C are valves  120 AV,  120 BV and  120 CV which are, like all of the valves shown in  FIG. 1 , controlled by control unit  500 . Any combination of valves  120 AV,  120 BV and  120 CV may be closed in order to take its corresponding filter unit off line. So, for example, when valve  120 AV is closed, filter unit  120 A becomes a pass through unit which produced no permeate. All of the tank water entering at intake  122 A merely passes to discharge  124 A. A malfunctioning filter unit may be taken off line while the remainder of the system continues to operate. 
     Periodically, the ceramic membranes of filter units  120 A,  120 B and  120 C will become obstructed with fat, dirt and other contaminants such that the permeate discharge rate through permeate discharges  126 A,  126 B and  126 C as measured by flow meters  128 A,  128 B and  128 C fall below a pre-selected minimum acceptable value. Moreover, the presence of fat, dirt and other contaminants on the inside walls of the small diameter ceramic channels of filter units  120 A,  120 B and  120 C will also obstruct the channels connecting between the intakes and the discharges of the filter units causing the pressure drop between the tank water inlet and the tank water discharge of each filter unit to increase above an acceptable level. In this example, when this pressure drop increases significantly above 20 psi, the control system initiates a high pressure reverse flow purge cycle which flushes highly filtered water at high pressure from a purge tank  202  back across the walls of the ceramic channels in ceramic filter units  120 A,  120 B and  120 C. In the alternative, or additionally, a reduction of measured permeate flow as indicated by flow meters  128 A,  128 B and  128 C may also be used as a primary or secondary indicator for initiating a purge cycle. 
     The pressurized air for driving the purge cycle is supplied by a compressor tank  204  which is essentially a pressurized tank for storing high pressure air. A pressure sensor  204 PS senses the internal pressure of compressor tank  204  for control unit  500 , and when valve  204 V is open, senses the pressure in compressor tank  204  and purge tank  202 . Generally, the purge cycle is initiated by the control unit by shutting down normal operations, pressurizing purge tank  202  and by causing pressurized clean permeate to flow back through the filter units. Control unit  500  can initiate a purge cycle when sufficient pressure is present in compressor tank  204 . The purge cycle begins by closing valve  101  and opening valve  104 . This shuts off the flow of tank water into the system and decreases the pressure in the tank water sides of the filter units. At the same time, control unit  500  closes valves  202 V 1  and  202 V 2  which isolates purge tank  202  and then opens valve  204  which causes the pressure in purge tank  202  to increase as it reaches equilibrium with compressor tank  204 . After pressure sensor  204 PS indicates that equilibrium has been reached, control unit  500  closes valve  204 V to isolate compressor tank  204  from the system and open valve  202 V 2  to allow pressurized clean permeate to flow back through the filter units causing the materials clogging the filter units to be purged into the stream on the tank water side of the filter units. Because valve  104  is open and valve  101  is closed, purged material and the permeate flow to valve  104  and flow into screen drum unit  22 . Once the purge cycle is completed, filter units  120 A,  120 B and  120 C may be returned to normal operation, wherein valve  101  is open, valve  204 V is closed, valves  202 V 1  and  202 V 2  are open and valve  104  is mostly closed. (Valve  104  is controlled by control unit  500  and may at times be partially open during normal operation to control pressure in the system.) Still further, during a purge cycle, it is possible to close one or more of valves  120 AV,  120 BV and  120 CV in order to selectively purge one or more of filter units  120 A,  120 B, or  120 C. 
     Tank water discharging from filter unit  120 C, in this example, comprises approximately 80% or 290 gallons per minute of the initial flow of approximately 350 gallons per minute entering filter unit  120 A. Under normal operating conditions, the tank water discharged from filter unit  120 C is returned to re-circulation pump  110 . Accordingly, in this example, the input from supply pump  29  may be approximately 60 gallons per minute. Thus, what is described above is a system which has a capacity of producing about 60 gallons of permeate per minute and therefore can accept and clean about 60 gallons of dirty process water per minute. As noted above, permeate from ceramic filter units  120 A,  120 B and  120 C collects in purge tank  202 . 
     In this example process water cleaning apparatus includes an ultra-violet sterilization unit  300  which further sterilizes permeate from purge tank  202 . An optional ultra-violet sterilization unit  300  receives permeate from purge tank  202  and subjects it to extremely intense ultra-violet light. A UV sensor  302  is located on ultra-violet sterilization unit  300  and is monitored by control unit  500 . UV sensor  302  provides a signal representing the amount of UV light in the water. Load monitors on each of the UV lights provide verification that the system is operating properly. Control unit  500  will alarm if the UV levels drop below a predetermined level or if the system is not fully operational. Subjecting the cleaned process water to intense UV light destroys substantially all of the remaining pathogens which may be present in the water. Other methods such as ultra-sonic pathogenic disruption device may be employed to destroy pathogens still present in the permeate. After leaving ultra-violet sterilization unit  300 , the hot cleaned process water passes through a delivery temperature sensor  402  and a delivery flow meter  404 . The hot, clean permeate leaving process water cleaning apparatus  10  is returned to the poultry processing facility and is used as clean hot scald water. In this example, the hot, clean reclaimed scald water, during normal operating conditions, is returned at a flow rate which is generally equivalent to the flow rate of hot dirty process water entering process water cleaning apparatus  10 . The applicant&#39;s have found in initial tests that with an extremely contaminated hot dirty process water input having Heterotropic Plate Count (HPC) pathogen levels raging between 3 to 4 million the output of the system may have an HPC level generally below 500. 
     It is to be understood that while certain forms of this invention have been illustrated and described, it is not limited thereto, except in so far as such limitations are included in the following claims and allowable equivalents thereof.