SLAUGHTERHOUSES

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SLAUGHTERHOUSES

• Patricia García García de Pereda
• Sonia García Redondo
• Beatriz Gómez Fernández
• Irene Huerta Illera

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1. General information

• 1.1 The slaughtering industry in the European
  Union

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1.2 Trends which may influence future resources
in the slaughtering industry
Larger installations
lower consumption per unit easier to solve
environmental problems

Food safety
Microbiological contaminants BSE crisis Increase
hygiene requirements ?Higher intensity of
cleaning and sterilisation?Increased consumption
of water and energy Packaging
Animal welfare/ethics
Reduction in the use of animal by-products in
animal feed
Eating quality
Control of carcase chilling processes
Working environment
health employees?not repetitive
operation Automation ? requirement for
energy Improved lighting and ventilation
Processing
Increase due to the demand of products prepared
quickly and simply
Other considerations
Not to clean intestines if a reduction of
water usage or pollution of the waste water is
required Cooling of blood requires considerable
amount of energy but provides better products and
less pollution Capital availability?production
improvements
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1.3 Technical characteristics of slaughterhouses
Classification those who carries out
slaugtherhouse operations only those
that also operates cutting plants to produce
specific meat cuts and portions. Most poultry
processors These are then packed as chilled or
frozen meat for sale. Concentration of the
industry into fewer larger units? downstream
activities and/or disposal or recycling of animal
by-products take place on the same premises as
slaughtering? reduce consumption and emission
levels on the integrated site as a whole Process
lines automated? Peak periods Lifetime 25-40
years
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1.5 Key environmental issues

• Air Water vapour from boilers
• Refrigerant gases
• Water high water consumption (EU MS meat
  legislation)
• high BOD, COD and TSS concentrations?blood
  treated at WWTP or pretreatment
• proportional to floor area used, method of
  slaughter, carcase dressing cooling and
  degree of automation
• Energy Refrigeration plant? 45-90 electrical
  energy
• Heat water? oil and/or natural gas
• Odour blood storage and handling, slurry,
  occupied lairages and inedible offal storage
• Noise animal noises during unloading and
  marshalling, vehicle movements, compressors

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1.6 Economic overview

• Diseases Meat consumption grows (developing
  world)? transport and risk of spread diseases
• Hidden costs in animal disease epidemics
  price paid to farmers for these animals
• Keep costs to a minimum contracts with larger
  companies
• fierce competition? bankrupt
• Costs provision and maintenance of abatement
  equipment
• cleaning up and repairing damage to plant
  and environment
• studies to avoid pollution
• changing technological and operational
  techniques
• Have increased for the treatment and
  disposal of animal by-products

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1.7 Food and veterinary legislation influences

• Directive set out the main hygiene requirements
  for slaughterhouses.
• some have significant environmental
  consequences (water energy consumption)
• Other food, veterinary and animal welfare
  legislation influences the applied processes and
  techniques.
• ABP Regulation prevent animal by-products
  derived from animals not fit for human
  consumption, following health inspection, from
  entering the feed chain and presenting a risk to
  animal or public health.

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2 Applied processes and techniques

• - Vary depending on the type of animal
• Machinery is being developed to mechanise carcase
  dressing and this tends to incorporate automatic
  carcase washing at every stage
• Animal reception and lairage animals are
  unloaded via ramps
• Animals arrive clean?wet hides and skins can
  deteriorate more quickly
• Animals are held in the lairage? recover from
  the stress of the journey.
• Slaughter Animals are moved along a walled
  passageway Animals are stunned using a
  captive bolt pistol
• The traditional stunning method for
  pigs involves applying scissor
• For pigs is also used CO2 baths.
• Animals could be killed by
  electrocution
• After stunning, animals are hung on an
  overhead rail

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• Bleeding starts just after stunning and is
  carried out rapidly, profusely and completely
• Is carried out according to certain
  religious rites.
• Consists on incising the carotid
  arteries
• Blood is pumped to a refrigerated and
  agitated tank ? additives to prevent
  coagulation.
• Environmental controls
• Hide and skin removal pull the hide/skin from
  the carcase.
• Sometimes are salted to improve preservation
• Head and hoof removal for cattle and sheep
• Pig scalding remove bristles, toenails and hair.
  
• Pig hair and toenail removal By an automatic
  de-hairing machine which brush or scrape the
  surface of the carcase.
• Pig singeing to remove residual hair, to provide
  a firmer skin texture and to eliminate
  micro-organisms.
• This unit consist on gas burners firing
  intermittently

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• Rind treatment to polish the skin and remove
  singe hair and other debris.
• Evisceration manual removal of the respiratory,
  pulmonary and digestive organs
• Splitting split the carcases along the spine
  using a saw
• Chilling Carcases are chilled to reduce
  microbiological growth
• The refrigeration systems use a
  refrigerant to transfer heat from the carcases
  to be cooled to ambient air
• Associated downstream activities
• Viscera treatment use of casings for example for
  sausage casings
• Hide and skin treatment the best option is
  salting? trimming reduces the amount of salt
  consumption as salt in waste water is difficult
  to treat

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2.2 Waste water treatments

• Types treatment on-site
• discharge directly to local water course
• Best ways of minimising
• preventing animal material entering the waste
  water stream
• avoiding the spillage of high strength organic
  liquids
• The sludge produced may be used or disposed of in
  a variety of ways
• The main uses of water and the waste water
  pretreatments are

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2.2 Waste water treatments

• Primary screening to remove organics debris and
  avoid blockages in the WWTP
• DAF treatment plant use of very fine air
  bubbles to remove suspended solids
• Secondary biological treatment which converts
  soluble and colloidal materials into biosolids
• Aerobic digestion (activated sludge) remove
  inorganic nutrients.
• Anaerobic digestion for water which has high
  organic load ? reduction of the concentration of
  impurities, low excess sludge production and
  biologically stable sludge.
• sludge used to be incinerated?
  limitations on land spreading
• storage, handling and spreading?odour
  problems
• Removal of nitrogen and phosphorus combine the
  carbon oxidation, nitrification and
  denitrification steps in a single process ?
  reducing the volume of air needed, elimination of
  the need for intermediate clarifiers and
  return-sludge systems
• Tertiary filtration, coagulation and
  precipitation as final cleaning step to reduce
  the BOD and suspended solids

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EMERGING TECHNIQUESBio-refining of animal
by-products to produce soil improvers and
fertilisers

• bio-refining treatment of Animal carcases and
  parts of carcases which sterilises pathogenic
  agents.
• heated in a hyperbaric reactor vessel at 180 -
  200 ºC and 1000 1380 kPa for 20 40 minutes.
• to create saturated steam, to hydrolyse and to
  inactivat pathogenic agents
• Environmental benefits inactivate pathogens,
  including TSE prions.
• Applicability this technique is not permitted in
  the EU.

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Biotechnological treatment of animal by-products
inorder to increase energetic valorisation

• Animal meal is sorted by grain size,
• Then treated with active microorganisms ability
  to degrade animal and vegetable fat, proteins and
  starch.
• An enzymatic reaction is activated by the
  micro-organisms. This substantially reduces the
  fat content and causes the calorific value of the
  material to increase.
• The time needed for the process is 15 20 days.
• The reaction conditions are between 20 - 27 ºC in
  semi-darkness.
• Applicability At the time of writing, this
  technique is not permitted in the EU,

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CURRENT CONSUMPTION AND EMISSION LEVELS

• Air Reported emissions of CO2, SO2 and NOX are
  shown in the next table.
• Water
• All slaughterhouses must have a pressurised
  supply of potable water within the meaning of
  Directive 80/778/EEC. This requirement for
  potable water to be used limits the opportunities
  for re-use of water.
• A non-potable water supply is authorised in
  exceptional cases for steam production, fire
  fighting and the cooling of refrigeration
  equipment,

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CURRENT CONSUMPTION AND EMISSION LEVELS

• Energy
• Slaughterhouses have an energy consumption even
  when no production takes place (heating and
  operation of the refrigeration system)?range of
  36 - 154 kWh/t carcase

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CURRENT CONSUMPTION AND EMISSION LEVELS

• Solid waste
• include lairage and vehicle wash solids animal
  by-products sludge, clean and contaminated
  packaging protective clothing and equipment.
• In the UK, solid wastes are commonly sent to
  landfill, but in Denmark, they are used in biogas
  production.
• Noise and vibration Typical noise levels found
  measured at the perimeter fence of a
  slaughterhouse or at the nearest buildings are
• 55 - 65 dB(A) during working hours
• 40 - 50 dB(A) in the evening
• 35 - 45 dB(A) at night,
• The main sources of noise and vibration are
  animal noises during unloading and marshalling to
  the slaughter-line vehicle movements
  compressors air conditioners ventilation fans
  and carcase splitting.

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BEST AVAILABLE TECHNIQUES

• This chapter are a reference point against which
  to judge the current performance of an existing
  installation or to judge a proposal for a new
  installation.
• The BAT conclusions are presented in this Figure

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Slaughterhouses and animal by-products
installations

• General processes and operations
• BAT for environmental management
• Integration of same site activities
• Collaboration with upstream and downstream
  activities
• Installation and equipment cleaning
• Treatment of waste water

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General processes and operations

• A system of environmental management
• The formation(training)
• The utilization of a program of planned
  maintenance
• The system application of management of the
  energy, the refrigeration, the light and the
  noises
• The management and minimization of the water
  quantities and emaciated detergents

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BAT for environmental management

• Definition of an environmental policy for the
  installation by top management
• Checking performance and taking corrective
  action,
• Review by top management.
• Giving consideration to the development of
  cleaner technologies

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Integration of same site activities

• For slaughterhouses and/or animal by-products
  installations, operating on the same site,BAT is
  to do the following
• re-use heat and/or power produced in one activity
  in other activities
• share abatement techniques, where these are
  required,

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Installation and equipment cleaning

• Manage and minimise the quantities of water and
  detergents consumed
• Select those detergents which cause minimum
  impact on the environment
• Where the equipment is suitable, operate a
  cleaning-in-place system

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Treatment of waste water

• Some examples of reached BAT
• To avoid the stagnation of the waste water
• To apply leaked(filtered) initial of solid by
  means of sieves
• To eliminate the fat of the residual water by
  means of a grid of fats
• To use a plant(floor) of flotation to eliminate
  solid additional
• To submit the effluent one to a process of
  biological treatment
• To eliminate the produced mires

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Additional BAT for the slaughter of large animals

• To stop the nourishment of the animals 12 hours
  before the slaughter
• To use a system of control of the water of drink
  according to the demand
• To douche the porks with atomizers temporized of
  water saving
• To re-use the cold water in the machines of
  depilated of porks
• To empty the stomaches and the intestines in I
  dry
• To regulate and to minimize the water used to
  displace the intestines

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7.1. General techniques applicable in
slaughterhouses

• This techniques consider the possible routes for
  recovery and recycling of by-products and waste
  to minimize the impact on the environment.
• Emissions from by-products can be prevented by
  storing, handling, processing and transferring
  materials within a suitable building.
• Storing animal by-products over prolonged periods
  at ambient temperature in the open air increases
  the risk of direct pollution ? Necessary to use
  freezers (energy, refrigerant leaks).
• It is necessary for all staff to be committed to
  its successful operation information and
  training about the use of the techniques.

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7.2 Slaughterhouses general techniques
applicable at installation level

• Delivery
• Vehicles are scraped before being cleaned to
  remove manure and to reduce the pollution burden
  in the waste water.
• At cleaning time, it is used a high-pressure
  trigger-operated adjustable water jet in order to
  reduce water consumption.
• Slaughter
• Process automation to avoid and minimise carcase
  rinsing, combined with clean slaughter
  techniques, that improve products quality and
  reduce the use of energy.
• Reduction of odours by the refrigeration of
  blood.
• Cleaning They are based on the minimisation in
  the use of water and, therefore, on the
  minimisation of the energy necessary to pump it
• Dry collection of floor waste.
• Maintenance techniques in order to avoid the
  waste of energy.
• Monitoring of compressed air use.
• Monitoring of ventilation use cleaning of
  filters, use of backward bowed centrifugal fans.
• Monitoring of hot water use. Reduce temperature
  in some applications.
• Groundwater can be used to cool refrigerant gases.

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7.2 Slaughterhouses Slaughter of large animals

• Animal reception and lairage
• Techniques to reduce BOD contents in wastewater
  and odours
• Cessation of feeding of animals 12 hours prior to
  slaughter ? () hygiene.
• Minimise animals time in the slaughterhouse to
  reduce manure production.
• Addition of dry bedding to existing bedding, to
  soak up manure ? (-) odours.
• Techniques to reduce the use of water
• Demand-controlled drinking water teats instead
  of water troughs ? () cleanliness.
• Showering of pigs, using water saving, timer
  controlled nozzles ? () less dust.
• Dry cleaning of the lairage floor and
  periodically cleaning it with water ?
• (-) odours, () less pollution of waste water.

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7.2 Slaughterhouses Slaughter of large animals

• Bleeding
• Optimisation of bleeding and blood collection
• The maximum quantity of blood is collected and
  contained at the bleed area. This reduces the
  requirement to manage dripping blood along the
  length of the slaughter-line.
• Use of hollow knives and blood recovering
  orifices under the animal?
• () more hygiene, less recovering time, more
  capacity, less pollution in wastewater.
• (-) high consumption of energy.
• Use of a squeegee for initial cleaning of the
  blood collection trough
• () Reduction of water consumption, waste water
  production and waste water contamination (less
  COD and BOD). Increased potential for waste
  minimisation. Increased potential for recovery or
  recycling of blood.

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7.2 Slaughterhouses Slaughter of large animals

• Pig scalding
• Insulation and covering of pig scalding tanks ?
  () Less consumption of energy and water. Less
  ventilation needs. Less production of odours
  (reduced evaporation).
• Water level control on pig scalding tanks ? ()
  Energy and water saving, by preventing the loss
  and need for replacement of water heated to
  approximately 60 C.
• Condensation/steam scalding of pigs (vertical
  scalding) ?
• () Reduced water and energy consumption. The
  lungs can be used.
• (-) The carcases will have to be washed prior to
  scalding. If there is any dirt on the skin, this
  will prevent the steam from contacting the skin.
  Expensive.

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7.2 Slaughterhouses Slaughter of large animals

• Pig hair and toenail removal
• Recirculation of water within pig de-hairing
  machines ? () Reduced water consumption and
  energy use.
• Replace irrigation pipes at the top of de-hairing
  machines, with nozzles ? () the spray to
  transport the hair away can be moved over and
  beneath the pig. Reduced water consumption.

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7.2 Slaughterhouses Slaughter of large animals

• Pig singeing
• Re-use of cooling water from the singeing kiln
  and use of nozzles fitted directed to the pigs ?
  () Reduced consumption of water.
• Heat recovery from pig singeing exhaust gases to
  preheat water ? () less energy, less odour.
• Post singeing showering with flat jet nozzles
  instead of shower heads ? The water supply can be
  arranged so that water only flows when a carcase
  is present (less consumption of water).

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7.2 Slaughterhouses Slaughter of large animals

• Rind treatment
• Replace irrigation pipes with flat jet nozzles ?
  () Less consumption of water.
• Evisceration
• Saw sterilisation in a cabinet with automated hot
  water nozzles ?
• () Reduced water consumption and energy too.
• Regulation and minimisation of water use for
  moving intestines ?
• () Reduced water consumption and reduced water
  entrainment of high BOD material, especially
  intestine contents.
• () The intestines can be used for sausage
  casings or pet food.

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7.2 Slaughterhouses Slaughter of large animals

• Chilling
• Blast-chilling/shock-cooling tunnel ?
• () Low shrinkage and small tunnel dimensions.
• () Low process temperatures cause surface
  freezing, which kills all non-cold tolerant
  bacteria and improves food safety.
• (-) The low chilling temperature, increases the
  energy consumption.
• Water-spraying/mist-cooling as a method of
  cooling pigs ?
• () Reduction in energy consumption for cooling
  and ventilation.
• () Low carcase shrinkage and high process
  temperature (avoid surface freezing).
• (-) High water consumption.
• NOT showering carcases before they are chilled in
  a chilling tunnel ?
• () Reduced water consumption.

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7.2 Slaughterhouses Slaughter of large animals

• Associated downstream activities - viscera and
  hide and skin treatments
• Removal of chopping blades from a by-product
  washer ?
• () Further recovery and recycling of substances.
• () Reduction in BOD, suspended solids, and other
  pollutants in wastewater.
• Dry emptying of stomachs ?
• () For for use in biogas production or
  composting.
• () Reduced water consumption and consequently a
  reduced volume and BOD loading of wastewater.
• () The stomachs can be used as human food, e.g.
  ox tripe, or for pet food.
• Dry collection of the contents of small
  intestines?
• () Reduced water consumption. Reduced volume and
  BOD loading of wastewater.
• () The intestines can be used for sausage
  casings or pet food.

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7.2 Slaughterhouses Slaughter of large animals

• Associated downstream activities - viscera and
  hide and skin treatments
• Dry emptying of pig intestines, which are not
  to be used for casings?
• () Reduced water consumption and consequently a
  reduced volume and BOD loading of wastewater. The
  water used is warm so there are also energy
  savings.
• () The reduced water content of the condemned
  intestines also reduces the energy costs
  associated with driving off the water at the
  rendering plant.
• () The manure can be used as fertiliser, after
  gas production in a biogas plant.
• Use of nozzles instead of showers to flush out
  large intestines (pigs), control of water
  consumption for small and large intestine
  washing, minimise water usage during rinsing of
  tongues and hearts ? () Reduced water
  consumption.
• Use of a mechanised fat trap for removing fat
  from water ?
• () Preventing the fat from dissolving makes its
  collection easier.
• () Reduction of BOD and N in waste water.
• () The fat can be used for rendering.

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7.2 Slaughterhouses Slaughter of large animals

• Associated downstream activities - viscera and
  hide and skin treatments
• Collection of the mucosa from small intestines
  (pigs)?
• () Reduction of organic matter (BOD) in the
  waste water.
• () Mucosa can be used by the pharmaceutical
  industry, for manufacturing heparin or it can be
  rendered or used in biogas installations.
• Trimming of all hide/skin material not destined
  for tanning immediately after removal from the
  animal, storage of hides/skins at 10 - 15 ºC,
  drum salting of hides and skins (also with added
  boric acid), dry collection of salt residues from
  hide, skin or fur preservation, preservation of
  hides and skins by refrigeration or by cooling
  with flaked or crushed ice. ?
• () Minimise the consumption of substances used
  in the preservation processes, of process
  chemicals, of water and reduce odour problems.
• () Prevent the growth of some bacteria.
• () Energy is saved.
• (-) The contamination of water is involved.
• (-) Salt can reduce the efficiency of the
  wastewater treatment.

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7.2 Slaughterhouses Slaughterhouse cleaning

• Use of detergents using enzymes
• () Less harmful to the environment.
• () Lower temperatures ? energy savings.
• () Lower COD than other chemicals.
• () Non-corrosive.
• Pre-cleaning blood and meat juice contamination
  with cold water
• ()Reduced energy consumption (it can be carried
  out with cold water).
• () Reduced use of detergents and contamination
  of waste water by detergents.
• CIP (Cleaning-in-place)
• () Reduction in the consumption of water,
  detergents and the energy needed to heat the
  water (the consumption levels are set).
• (-) High capital investment.
• Use of cyclonic vacuum cleaners
• () Reduced water contamination.
• (-) Increased use of energy compared to simply
  hosing down, or using a squeegee.

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7.2 Slaughterhouses Storage and handling of
slaughterhouse by-products

• Segregated storage and handling of different
  kinds of by-products
• By-products can be collected, handled and stored
  separately or in categories, depending on their
  further use or disposal route and on the
  potential environmental consequences of mixing
  them.
• () Reduced odour emissions associated with the
  storage of malodorous by-products.
• () Reduced cross contamination between different
  by-products.
• () The refrigeration capacity required will be
  less.
• () Segregation enables individual by-products to
  be used instead of disposed of.
• () Reduced waste disposal costs.

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7.2 Slaughterhouses Slaughterhouse waste water
treatment

• Moving bed trickling filter - for the treatment
  of air, water and air/water mixtures
• () Low energy consumption.
• () COD levels and nitrogen compounds are reduced
  by 90 and 55 , respectively.
• Treatment of slaughterhouse waste water at
  municipal WWTPs
• () No need to reduce BOD levels.
• (-) Necessary to remove fats and gross solids
  before the treatment.
• () Waste water from slaughterhouses contains
  easily degradable organic matter with a
  favourable CN ratio complete denitrification is
  obtained easily.
• Use of sequencing batch reactors (SBR) in
  slaughterhouse wastewater treatment
• () The system allows equalisation, COD removal,
  nutrient removal and clarification.
• () The energy consumption is low (no need for
  recirculation between tanks).
• () No requirement to use chemicals ? No
  chemically contaminated sludge ? Composting.
• (-) CO2 and nitrates emissions ? Global warming.
• () Flexible technique. Not requiring much space
  and not requiring a clarification system.

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7.2 Slaughterhouses Slaughterhouse waste
treatment

• Microbiological treatment of slaughterhouse
  waste
• () Waste water treatment producing water and
  solids which can be used instead of needing to be
  disposed of.
• The sludge produced by the digesters is dewatered
  to give a biomass with a commercial value as a
  fertiliser.
• Liquid is used for land spreading, or used for
  belt washing.
• The final effluent is suitable for yard washing,
  after veterinary approval.
• () Capable of treating high-strength wastes with
  a COD content of over 100 g/l and of adapting to
  a wide range of pollutant loads.
• (-) Some energy use for the operation of the
  process and odour from the biomass.