Cleaner production of meat processing

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Cleaner production of meat processing

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• Dr. Willem Marsman
• DVM

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Meat processing

• Is the generic term used to describe the industry
• Abattoir/slaughterhouses
• Meatpacking plants-undertake slaughter and
  carcass dressing but also the further processing
  of meat products and byproducts

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Focus of this guide

• Since livestock slaughter along with its
  associated activities contributes the most to
  pollution, this guide focuses on abattoir
• Basic principles are independent of plant
  capacity
• Guide refers to cattle and pigs however
  principles will apply also to other species

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Cleaner production

• Application of cleaner production to medium and
  large scale abattoirs
• An increasing trend in many countries is for
  abattoirs to incorporate rendering facilities to
  process solid by-products materials into meat
  meal and tallow

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Units of production

• Per head of livestock slaughtered
• Tonne of live carcass weight LCW
• Tonne of dressed weight-DW
• Tonne of hot standard carcass weight-HSCW

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Process overviewpigs

• Pre-handling of pigs, generally fasted for a day
  to reduce the amount of intestinal contents
• Stunning and bleeding
• Dehairing and finishing
• Evisceration and splitting
• By products processing
• rendering

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Products and by products from slaughter of 90 kg
pig

• Boned meat 56.6kg- 64
• Inedible material for rendering 18 kg-20(bones,
  fat, head, hair, condemned offal etc)
• edible material (tongue, liver ,heart, kidneys,
  trotters)
• 9 kg-10
• blood 2.7 kg-3
• miscellaneous (stomach contents shrinkage, blood
  loss etc. 2.7 kg -3

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Process overviewcattle

• Live weight can vary from 250 kg to 600kg
  depending on the age and breed of the animal
• As a guide heifers 250-300kgcows
  350-400kgsteers 400-600 kg
• Processing rates in the United States now average
  350 head per hour

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Continue cattle-basic process

• Pre-handling of cattle-animals are rested for one
  or two days before slaughter
• Stunning and bleeding
• Dressing and hide removal
• Evisceration
• Cutting and boning (also hot boning)
• Inspection
• By-products

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Products and by-products from the slaughter of
400 kg beef cattle

• Boned meat-152 kg-40
• Inedible material for rendering 155 kg-39
• Hide 36 kg-7
• Edible offal 19 kg-5
• Blood 12kg- 3
• Miscellaneous (paunch manure, shrinkage ,blood
  losses etc.) 26 kg-6

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By product processing

• By products can contribute significantly to the
  profitability of an abattoir since they have a
  commercially value
• If animal by product are not used effectively a
  valuable source of revenue is lost. And the added
  and increasing cost of disposal of these products
  is incurred by the company
• Also from an environmental perspective
  utilization of by product reduces the overall
  environmental load of the process

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Continue by-productinclude

• Edible offal
• Edible fat for shorthening/margarine/sweets/chuwin
  g gum
• Bone soup consumption or manufacture of buttons,
  knife handles and bone meal
• Blood for human consumption and for animal feed,
  pharmaceuticals and food additives (emulsifiers,
  stabilizers, clarifiers, nutritional additives,
  egg albumin substitute) fertilizer, animal feeds,
  industrial application
• Glycerin for numerous industrial uses as
  nitroglycerine, ointment bases ,solvents ,food
  preservatives and plasticizers

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Continue by-products

• Intestines for sausages casings, strings of
  musical instruments and surgical ligatures
• Gelatin for confectionery items, ice cream and
  jellied food products
• Rennin for cheese making
• Pharmaceutical products
• Livestock feed (high in protein, fat, minerals)
• Pet food and feed for fish farming

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Continue by-product

• Hides and skin for leather, fur or leather goods
• Inedible fats for use in industrial products such
  as tires, lubricants, insecticides and germicides
• Hair for brushes, felt, rugs, upholstery, plaster
  binding and insulation
• glue

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Products and by-products from the slaughter of
400 kg beef cattle

• Boned meat-152 kg-40
• Inedible material for rendering 155 kg-39
• Hide 36 kg-7
• Edible offal 19 kg-5
• Blood 12kg- 3
• Miscellaneous (paunch manure, shrinkage, blood
  losses etc.) 26 kg-6

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Environmental impacts

• High consumption of water
• The discharge of high strength effluent
• Consumption of energy
• Noise, odor, solid waste

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Water consumption

• Hygiene standards
• Watering and washing livestock
• Cleaning process equipment, work areas, carcasses

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Effluent discharge contains

• (A high level of organic material,
  fat,nitrogen,phosphorus and salt)
• Blood
• Fat
• Manure
• Undigested stomach contents
• Cleaning agents

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Continue environmental issues

• If irrigation is not managed correctly, dissolved
  salts contained in the effluent can adversely
  affect soil structure and caused salinity
  problems
• Nitrogen and phosphorus can also leach to
  underlying ground water and affect its quality
• When directly into water bodies the high levels
  of organic matter can deplete oxygen levels and
  thus degrade water quality

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Environmental continue

• Reception of livestock
• Truck washing
• Cattle washing

• Effluent containing manure wastes
• High water consumption
• noise

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Environmental continue

• Stunning and bleeding

• Effluent with high organic load, especially when
  blood is discharged

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Environmental continue

• Hide treatment pigs

• Energy consumption for hot water used for
  scalding
• Generation of putrescible by-products
• Effluent with high content of organic matter

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Environmental continue

• Splitting and evisceration

• Energy consumption for equipment sterilization
• Generation of putrescible by-products
• Effluent with organic load

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Environment Continue

• refrigeration

• High energy consumption
• Fugitive losses of refrigerants, e.g. CFCs or
  ammonia

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Environment continue

• Cutting and boning

• Electricity consumption
• Generation of putrescible by-products
• Energy consumption for equipment sterilization

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Environment continue

• Casing and offal processing

• Effluent with very high organic load
• Very high water consumption

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Environment continue

• rendering

• Effluent with very high high organic load
• Potential for odor generation
• High energy consumption

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Environment continue

• cleaning

• High water consumption
• Consumption of chemicals
• Large volumes of effluent with high organic load

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Environment continue

• Energy consumption-thermal energy (steam and hot
  water)-electricity (machinery, refrigeration,
  ventilation,lighting compressed air)
• Byproducts-odor-high risk materials
• Air emission-air pollutions include oxides of
  nitrogen and sulphur and suspended particulate
  matter

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Environment continue

• Odor, biological treatment systems are another
  common source of odor-upsetting microbiological
  balance of the system, resulting in the release
  of hydrogen sulphide and other odorous compounds
• Refrigerants-chlorofluorocarbons (fugitive loss
  to atmosphere-ozon depletion)-replacement with
  ammonia is important
• noise

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Environmental indicatorswater consumption

• A factor that affects water consumption is
  cleaning practices ,plants which produce meat for
  export often have stricter hygiene requirements
  and therefore may consume more water for cleaning
  and sanitizing
• Slaughter, evisceration and casing and offal
  processing tend to account for a large proportion
  of total water use

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Environmental indicatorswater consumption

• Water consumption is 225 l/head for pigs as
  average and 860 l/head for cattle as average

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Environment indicatorseffluent discharge

• high organic loads due to presence of blood, fat,
  manure and undigested stomach contents
• High levels of fat
• Fluctuations in pH due to caustic and acid
  cleaning agents
• High levels of nitrogen, phosphorus and salt
• High temperature

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Environment indicatorseffluent discharge

• The concentration of organic matter is a key
  indicator of effluent quality and is commonly
  expressed as chemical oxygen demand (COD) or
  5-day biochemical oxygen (BOD5)

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Environmental indicatorseffluent discharge

• Animal fats are long chain fatty acids and
  glycerol, collectively referred as fats, oils and
  greases
• Fats of animals are generally biodegradable and
  have high specific BOD5 ,more than 2 g BOD5 per
  gram lipid
• Nitrogen in abattoirs effluent occurs mainly in
  the form of ammonia due to the breakdown of
  proteinaceous materials into amino acids and the
  ammonia, however the nature of the ammonia
  species present depends on the ph. Therefore
  nitrogen levels in abattoir effluent are commonly
  expressed as total nitrogen

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Environment indicators effluent discharge

• BOD (mg/l) pig
• cattle
• COD (mg/L) pig
• cattle
• Suspended solids (mg/l)
• pig
  
• cattle
• Total nitrogen (mg/L)
• pig
• cattle

• 1250
• 2000
• 2500
• 4000
• 700
• 1600
• 150
• 180

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Environmental indicatorseffluent discharge

• Total phosphorus (mg/L) pig
• cattle
• gtOil and grease(fat)
• (mg/l) pig
• cattle
• gtpH pig/cattle

• 25
• 150
• 270
• 7.2

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Environment discharge

• Organic matter- originates from all areas where
  water comes into contact with carcasses, manure,
  offal and blood etc.
• Blood- also the most significant source of
  nitrogen
• Phosphorus originates from manure and undigested
  contents and blood processing within the
  rendering plant

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Environment continueeffluent discharge

• Salt- originate from manure and undigested
  stomach contents and also from rendering and
  pickling processes and perhaps raw water
• Fat originates from trimmings that are allowed to
  fall on the floor and from carcass washing

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Environment continueeffluent discharge

• At those plants where rendering occurs the
  rendering plant is generally the largest single
  source of effluent contamination.
• Rendering typically contributes about 60 of a
  plant total organic load but only 5-10 of the
  total volume

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Environment indicatorseffluent discharge per head

• BOD5 (kg/head)-pig
• cattle
• Total nitrogen (kg/head) -pig
• cattle
• Total phosphorus (kg/head) -pig
• cattle

• 0.5-20
• 1-5
• 0.075-0.25
• 0.25-1.0
• 0.015-0.03
• 0.030-0.1

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Energy consumption

• If rendering and pig scalding occur at an
  abattoir this will add substantially to overall
  energy consumption
• About 80-85 of an abattoir total energy is for
  thermal energy
• Fuel used for steam production in boilers is
  typically coal or fuel oil. However the use of
  natural gas and liquid petroleum gas is
  increasing due to environmental pressure to burn
  cleaner fuels

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Energy consumption continue

• It is also possible to recover waste heat from
  high temperature rendering processes to heat
  water
• The remaining 15-20 of an abattoir energy
  consumption is provided by electricity,
  refrigeration accounts for a significant of
  electricity use

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Energy consumption continue

• A useful indicator of plant performance energy
  use is expressed per unit of production
• An indication is for pig 27kW.h/head and for
  cattle 61kW.h/head

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Benchmarks

• Water consumption
• Energy consumption
• Organic load in effluent (COD or BOD5)
• Nitrogen loads
• Phosphorus loads

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benchmark

• The lack of environmental benchmarking in meat
  industry is thought to be due to the considerable
  variation in production processes and scales of
  operation within the industry.
• No widely recognized standard unit of production
• In order to compare one process with another, or
  to compare a process with a specified benchmark
  the scale, age ,efficiency and type of process
  should be similar to enable sensible comparison

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Benchmark for pig abattoirs 90 kg

• Water-L/animal
• Heat and electricity-kW.h/animal
• BOD5-g/animal

• Traditional1400
• Average700
• Best available300
• Traditional125
• Average50
• Best available30
• Traditional 2500
• Average 1000
• Best available 500

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Benchmark for cattle abattoir-250 kg cattle

• Water L/animal
• Heat/electricity- kW.h/animal
• BOD5-g/animal

• Traditional 5000
• Average 2500
• Best available1000
• Traditional 300
• Average 125
• Best available70
• Traditional 5500
• Average 2500
• Best available1200

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Cleaner production opportunities

• Focus on
• Reducing the consumption of resources (water and
  energy)
• Increasing product yields
• Reducing the volume and pollutant load of
  effluent discharges
• Individual operators practices

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general

• General housekeeping
• 1. are work areas tidy and uncluttered to avoid
  accidents
• 2. is there a good inventory control of
  consumables such as cleaning chemicals, packaging
  materials, food additives etc.to avoid waste
• 3. are employees aware of the environmental
  aspects of company operations and their personal
  responsibilities
• 4.are staff trained in good cleaning practices
• 5.is there a schedule for regular maintenance
  activities to avoid inefficiencies and breakdown

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Water consumption

• Water saving ideas
• 1. is dry cleaning of trucks undertaken prior to
  washing with water
• 2. are high pressure ,low volume spray nozzles
  used
• 3.is high pressure used rather than high volume
  for cleaning surfaces
• 4 are automatic operated scalding chambers used
  rather than scalding tanks for the dehairing of
  pigs
• 5.are offal transport systems used that avoid or
  minimize the use of water.
• 6.are dry dumping techniques used that avoid or
  minimize the use of water for the processing of
  cattle paunches and pig stomachs, instead of wet
  dumping techniques

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water consumption

• 7.is there a reuse of relatively clean waste
  water from cooling systems ,vacuum pumps etc. for
  washing livestock
• 8.is there a reuse of final rinse waters from
  paunch and casing washing for other non critical
  cleaning steps in the casing department
• 9.is there a reuse of waste water from slaughter
  floor ,carcass washing, viscera tables and hand
  washbasins for the washing of inedible products
• 10.is there a reuse of cooling water from the
  singeing process for other application in the
  pig dehairing area
• 11.is there a reuse of the final rinse from
  cleaning operations for the initial rinse on the
  following day
• 12.is there a use of dry cleaning techniques to
  pre-clean process areas and floor before washing
  with water.
• 13.are automatic control systems used to operate
  the flow of water in hand wash stations and knife
  sterilizers

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Water consumption

• Analyze water use patterns by installing water
  meters and recording water consumption
• Identify leaks and other areas of unnecessary
  waste
• Installing automatic shut off equipment and flow
  restrictors.Automatic control of water use

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Water consumption

• The optimum rate can be determined by
  investigating each process in detail and
  undertaking trials
• For example defrost water from refrigeration
  units could be reused for non critical
  applications.
• Even waste water from slaughter floor, wash
  basins, knife and implement sterilizers and
  carcass washing could be reused for example for
  stockyard cleaning, hide cleaning and livestock
  washing as long fresh water (potable) is used for
  the final livestock rinse

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water consumption

• Effluent discharge quality standards will become
  tighter

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effluent

• Reducing effluent loads
• 1. is there a segregation of blood by designing
  suitable blood collection facilities and allowing
  sufficient time for bleeding, typically seven
  minutes
• 2.is there a sweep up of solids materials done
  for use as byproducts, instead of washing them
  down the drain
• 3.are drains fit with screens and /or traps to
  prevent solid materials from entering the
  effluent system
• 4. is offal transport systems used that avoid or
  minimize the use of water.

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effluent

• 5.are water sprays used with a pressure of less
  than 10 bar for carcass washing to avoid removing
  fat from surface
• 6.are dry cleaning techniques used to pre-clean
  process areas and floors before washing with
  water
• 7.are high strength effluent streams such as
  rendering effluent and waste waters from casings
  and paunch washing segregated

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effluent

• Efforts to reduce water consumption will also
  result in reduced effluent volumes
• Opportunities for reducing the pollutant load of
  abattoir effluent principally focus on avoiding
  the discharge as blood, undigested stomach
  contents, fat and scraps of meat
• Blood recovery can degrease organic loads by
  approximately 40

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energy

• Energy saving
• 1.is there a switch off program implemented and
  are sensors installed to turn off power down
  lights and equipment when not in use
• 2.is insulation improved on heating and cooling
  systems and pipe work
• 3.are scald tanks insulated and covered
• 4.is there a recover of waste heat from effluent
  streams, vents,exhaust and compressors

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energy

• 5.is there a recovery of evaporative energy in
  the rendering process, using multi effect
  evaporators
• 6. is there a leak free compressed air system
  maintained
• 7.is there a favor of more efficient equipment
• 8. is maintenance improved to maximize energy
  efficiency of equipment
• 9. is there an optimal combustion efficiency on
  boilers
• 10.are steam leaks eliminated

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energy

• Simple house keeping and optimization of existing
  processes can give significant reductions
• Replacing fuel oil or coal with cleaner fuels
• For some plants it may also feasible to recover
  methane from anaerobic digestion of high strength
  effluent streams to supplement fuel supplies

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By products

• By products
• 1.are all by products segregated
• 2.are by products not contaminated with water or
  material that would limit or prevent their use
• 3.are by products stored correctly to maintain
  quality and maximize the viability of reuse
  opportunities

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Live stock reception

• Trucks are washed and sometimes disinfected
• Animals fasted 1-2 days to reduce quantity of
  stomach contents
• Holding prior to de- stress animals
• Pigs are susceptible to heat stress and therefore
  sprinkler systems are used
• Livestock are washed

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Live stock

• livestock reception
• -input
• live pig 100kg
• water for cleaning 15 liter
• bedding if used 2.5kg
• live cattle 250 kg
• water for cleaning 75 liter
• bedding if used 7.5 kg
• -

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Live stock

• Output
• live pig 100kg
• waste water 15 liter
• BOD 0.02 kg
• Solid waste 1.5 kg
• Live cattle 250 kg
• Waste water 75 liter
• BOD 0.1 kg
• Solid waste 5 kg

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Effluent comparison previous slides

• -input
• live pig 100kg
• water for cleaning 15 liter
• bedding if used 2.5kg
• live cattle 250 kg
• water for cleaning 75 liter
• bedding if used 7.5 kg

• Output
• live pig 100kg
• waste water 15 liter
• BOD 0.02 kg
• Solid waste 1.5 kg
• Live cattle 250 kg
• Waste water 75 liter
• BOD 0.1 kg
• Solid waste 5 kg

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effluent

• For truck washing water should be used only after
  dry cleaning
• Manual cleaning of livestock should be restricted
  to those that needed it.A 20-35 diameter hose
  fitted with a 9-10 mm nozzle will maximize
  efficiency
• Screening of waste water can best be achieved
  using rotating screens or static run down screens

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Stunning and bleedingpigs/cattle

• -input
• live pig 100kg
• water 5 liter
• carbon dioxide 0.16 kg
• live cattle 250 kg
• water 5 liter

• -output
• bled pig 95 kg
• blood (assuming 80 recovery) 4kg
• waste water 6 liter
• BOD (blood loss)0.2 kg
• Bled cattle carcass 238 kg
• Blood (assuming 80 recovery) 10 kg
• Waste water 7 liter
• BOD (blood loss) 0.4 kg

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Stunning and bleeding

• Blood constitutes the highest pollution
  load,blood has high organic load with its organic
  load equivalent estimated to be 0.14-0.18 kg BOD5
  per kg and blood is main contributor to nitrogen
  loads in effluent
• The presence of water reduces the efficiency of
  coagulation processes and if blood is to be dried
  increases the energy required to evaporate the
  water content

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Stunning and bleeding continue

• After blood ,fat is the next most important
  contaminant in effluent, fat blinds screens will
  be blocked and greater use of hot water to clean
  them
• Two way drain in bleeding areas with removable
  plugs/valves should be installed and proper
  collecting possibilities for only collecting
  blood
• Blood should be chilled quickly when used for by
  product

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Hide treatment pigs

• -input
• bled pig carcass 95 kg
• water 60 liter
• oil 0.6 liter
• gas 0.5 m3(if used instead of oil)

• -outputs
• de-haired pig carcass 93 kg
• waste water 60 liter
• BOD 0.3 kg
• Pig hair 1kg
• Scrapings 1 kg

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Hide treatment pigs

• Water consumption high, waste water contained
  high level of organic matter, scalding tanks have
  temperatures of up to 75 degrees Celsius which if
  passed can melt fat
• Consumes lot of energy
• Insulate scalding tanks, waste water should pass
  a sedimentation tank, interceptor trap or sand
  trap before discharge (investment high)

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Hide treatment pigs

• Automatic operated scalding chambers use less
  water, water consumption can be reduced by 50-70
  (investment high)
• Hair collecting is essential before it enters
  drainage system
• Singeing oven must be insulated and recovery of
  heat, use of solenoid switches

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Hide removal and dressing cattle

• -input
• bled cattle carcass 238 kg
• water 5 liter

• -output
• dehided cattle carcass 207 kg
• hide 15 kg
• heads,hoofs,tail etc 16 kg
• fleshing 3 kg
• waste water 5 liter

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Hide removal and dressing cattle

• If hides are sent to tannery without
  fleshing,hides are packed unwashed in
  salt,fleshing are made up of fat and flesh and
  represent about 15 of the weight of the hide
• Cattle hide accounts for 5-9 of the live weight
  of beef cattle

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Hide removal and dressing of cattle

• When hides are preserved by salting,saturated
  brine or salt crystals are used. Up to 4 liters
  of saturated brine can be lost for each hide
  treated. These spent brine can pose a substantial
  disposal problems
• Typical consumption of salt for conserving hides
  is about 350 kg per tonne of hide,if stored 6
  weeks or less salt can be reduced to 150 kg etc.

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Evisceration and spitting

• -input
• dehaired pig carcass 93 kg
• water 40 liter
• dehided cattle carcass 207 kg
• water 100 liter

• -output
• split pig carcass 74 kg
• intestinal tract 10 kg
• plucks and edible organs 3 kg
• by-products 5.5. kg
• waste water 40 liter
• BOD 0.05 kg
• Split cattle carcass 125 kg
• Intestinal tract 60 kg
• Plucks and edible organs 9 kg
• By-products 12 kg
• Waste water 100 liter
• BOD 0.12 kg

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Evisceration and splitting

• Carcass washing can be a significant source of
  water waste and effluent contamination. In manual
  operations there is a tendency to use more water
  than is necessary, automatic carcass washing
  units sprays are recommendable
• Water pressure greater than 10 bar for carcass
  washing can remove fat from surface and water
  temperatures greater than 30 Celsius can further
  exacerbate fat loss

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casing

• -input
• pig casing 10 kg
• water 50-100 liter
• cattle casing 30 kg
• water 300-500 liter

• -output
• washed casings 10 kg
• waste water 50-100 liter
• BOD 0.1-0.3 kg
• Washed casings cattle 30 kg
• Waste water 300-500 liter
• BOD 1-1.5 kg

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casings

• Water consumption for casing processing is very
  high and can be up to 20 of total water
  consumption
• Fasting is essential
• An assessment should be made if casing cleaning
  is a profitable choice, perhaps better sending
  the empty intestines for inedible rendering
• New techniques for emptying guts sets for pigs
  without use of water

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Paunch washing cattle

• Input
• Cattle paunch 50 kg
• Water 200 liter

• -output
• washed cattle paunch 10 kg
• paunch manure 40 kg
• waste water 200 liter
• BOD 0.5 kg

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Paunch washing cattle

• Water consumption very high
• Paunch manure contains high concentrations of
  organic solids and other pollutants. BOD5
  concentrations have been estimated to be about
  50000mg/l
• The undigested solids are not easily degraded in
  biological treatment systems and build up as
  sludge in the system reducing overall treatment
  capacity
• An assessment should be made of whether paunch
  washing is a profitable choice

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Paunch washing

• It was estimated that converting a wet dump
  system to a two step system could reduce the
  total loading of a typical beef abattoir by
  18-33 for total solids,16-31 for COD,9-18 for
  total nitrogen and 20-46 for total Phosphorus

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Paunch manure

• Is a ideal medium for composting or vermiculture
  (worm composting) along with other waste
  materials.
• After composting it can be used or marketed as a
  fertilizer or soil conditioner
• Prior composting is preferable before paunch
  manure is spread directly onto agriculture land

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rendering

• -input
• raw materials (offal,dead animals) 1000 kg-
  approximately 60 of the weight of the raw
  materials is water ,which ends up as condensate
  waste water as a result of the rendering process)
• fuel oil for steam generation 60 kg
• electricity 70 kW.h
• water for boiler 150-200 liter
• water for condenser 200-500 liter
• water for cleaning 200-300 liter

• -outputs
• bone meal 280 kg
• fat 110 kg
• waste water 1000-1600 liter
• COD 5 kg
• Total nitrogen 0.6 kg

87
rendering

• Commodities as meat meal,bone meal, tallow and
  also pet food
• Simple batch cooking in which fat is removed by
  hydraulic presses or continuous systems

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rendering

• Pre-crushed material
• In rendering cooker-high temperature which
  evaporate water and sterilize it
• Fat allowed to drain from mixture in percolator
  pan and remainder of the fat is pressed out
  mechanically either in a hydraulic press (batch
  process) or continuous in a screw process
• The press cake is milled to produce meat meal and
  bone meal
• Fat is further refined to remove impurities by
  precipitation, centrifugation etc

89
rendering

• Effluent of rendering contains very loads of
  organic material
• Compromises condensate from dry rendering, stick
  waters from wet rendering, decanters and blood
  coagulation and from polisher centrifuges

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rendering

• Energy consumption is very high
• Rendering materials can cause extremely bad odors
• Raw materials should received promptly, delays in
  processing result in poor quality raw materials
  which lead to lower yields, lower quality
  products and difficulties in processing raw
  materials
• Rendering materials should be kept cool at about
  10-15 Celsius or lower

91
rendering

• Heat from cookers can be recovered in multiple
  effect evaporators and used to preheat raw
  material, this can reduce energy consumption from
  about 60kg to 35 -40 kg oil per tonne of raw
  material
• The effluent stream from rendering along with
  other high strength streams as paunch and stomach
  dumping could be collected and treated separately

92
rendering

• Segregated high strength effluent streams could
  be anaerobically digested to produce methane rich
  biogas

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cleaning

• Cleaning accounts for 20-25 of total water
  consumption
• Waste water from cleaning contains a high organic
  load as well detergents and disinfectants
• Dry cleaning is essential before washing with
  water
• Industrial vacuum cleaners have been used in
  boning rooms

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cleaning

• Hoses should be fitted with spray nozzles,
  pressure of 25-30 bar
• Flat jet nozzles should be used, spray angles of
  60
• First rinse with cold water and than warm water
• Detergents and disinfectants should be monitored
  (concentration, new types of detergents which are
  more environmental friendly are recommended)

95
cleaning

• Chemical sanitizers can be more effective in
  bacteriological control less damaging to the
  building and safer for personnel than large
  quantities of hot water
• Regular maintenance of spray nozzle wear is
  essential
• Double insulated knife sterilizers reduce the
  rate of overflow required to maintain the
  required temperature. For a 3 liter bowl this can
  mean an overflow rate of 15 l/hr compared with
  36l/h for conventional sterilizers

96
Compressed air

• Usually compressors are electrically powered and
  cooled with water or air.
• It is important to check the compressed air
  system frequently
• Cooling water can be recirculated via a cooling
  tower, alternatively the cooling water can be
  reused for other purposes

97
Steam production

• Steam is produced in a boiler and distributed
  throughout the plant through insulated pipes.
  Condensate is returned to condensate tank, from
  where it is circulated as boiler feed water
  unless it is used for heating in the production
  process

98
Steam production

• Other parameters are pressure, fuel type,
  maintenance, operation
• Combustion of fuel oil results in emissions of
  carbon dioxide, sulphur dioxide, nitrogen
  oxides,polycyclic aromatic hydrocarbons
  (carcinogenic!)
• Some fuels contains 3-5 sulphur and result in
  sulphur dioxide emissions of 50-85 kg per 1000
  liters of fuel oil-
• Sulphur dioxide converts to sulphuric acid
  resulting in formation of acid rain
• Nitrogen oxides can result in lung irritation

99
Steam production

• If oil is spilled it can cause serious pollution
  of soil
• For inefficiently operated boilers the amount of
  feed water required can be excessive and need of
  additional boiler chemicals and increased fuel
  consumption
• Fuel oil with less sulphur is more expensive
  however the efficiency of boiler is increased
  and emission less

100
Steam production

• Purchasing an oversize boiler for the sake of
  contingency may not really necessary
• Proper insulation can reduce heat loss

101
Water supply

• Treatment normally consists of aeration and
  filtration through gravel or sand and
  chlorination
• Energy efficient pumps should be installed

102
Refrigeration and cooling

• All cooling systems should be closed circuit
  systems and free of leaks
• If CFC based refrigerants are used there is a
  risk that refrigeration gases will be emitted to
  the atmosphere, contributing to the depletion of
  ozone layer
• Insulating cold rooms and pipes is essential
• Self closing doors are recommended

103
Cleaner production

• Planning and organization
• Pre-assessment
• Assessment
• Evaluation and feasibility study
• Implementation and continuation

104
Cleaner production of meat processing-end