Rendering of wasted meat from slaughter House

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Rendering is the most common method used to repurpose slaughterhouse waste involves their conversion by rendering plants into industrial byproducts such as  Protein fats and oils, in the form of lard and tallow , fertilizers derived from organic compost , biogas through methane production .

Rendering animal by-products (ABP) became a widespread and efficient practice in the 20th century meat industry, a practice dating back to ancient times when animal skins provided shelter and clothing and tallow was made into soap and candles. 

It is a cooking or drying process that destroys pathogens and stabilises animal by-products, removing the moisture and separating the fat and protein meal components into a range of marketable products. 

A typical rendering process is shown in Figure 1 and includes size reduction, cooking and separation of fat from protein.

• Meat waste parts from Pigs ,cows and other Animals which  Cant be used  or sold by the  SH
• Meat waste parts from chicken slaughter house or secondary process for chicken processed  Products 
• algies 
• Black solider Fly (BSF ) 
• Fisheries and secondary  Fish Processing plants 

• Meat waste parts from Pigs ,cows and other Animals which  Cant be used  or sold by the  SH
• Meat waste parts from chicken slaughter house or secondary process for chicken processed  Products 
• algies 
• Black solider Fly (BSF ) 
• Fisheries and secondary  Fish Processing plants 

 The global meat consumption has seen a 40% increase in the last decade (Brennan et al., 2021). In 2020, it was reported that approximately 252.6 million metric tons (MT) of meat were produced globally, including 99.1 million MT chicken, 95.8 million MT pork, and 57.7 million MT beef (Wang et al., 2022) 

 This section explain briefly the most common operations taken at slaughter house   for treating  waste from Processing of animals and fish : 

• RAW ABP IS BROUGHT TO THE RENDERING PLANT  ( OFFAL,RED MEAT,PIGS)
• PRIMARY SIZE REDUCTION IS DONE ON A MEAT CRUSHER
• SECONDERY SIZE REDUCTION AND PUMPING OF MEAT BY LAMELA PUMP TO PROCESS TANK
• PROCESSING UNDER PRESSURE (STEAM) AND MECHANICAL HIGHE SPEED HOMOGENIZER WHICH TURN THE MEAT INTO "SOUP" LIKE SOLUTION AFTER STERILIZATION AT 142 DEG c
• SEPERATION BY DECANTER OR TRI-CANTER OF FAT-SOLIDS-WATER 
• SOLIDS ARE DRIED TO REMOVE WATER IN A PADDLE OR DISK DRYER TO YIELD PROTEIN 60-65% AND LESS THEN 10% MOISTURE,AFTER DRYING THE PROTEIN IS COOLED TO 60-70 DEG C
• EDIABLE FAT IS POLISHED IN HIGH SPEED CENTRIFUGAL SEPERATOR TO YIELD 99.9% OIL 
• QUALITY ASSURENCE FOR BOTH PRODUCTS 
• WASTE WATER ARE SENT FOR ANAEROBIC TREATMENT WITH HIGH CONTENT OF NUTRIENTS FOR PRODUCTION OF BIOGAS.

 This section provide information and links to manufacturers of primary size reduction equipment for meat and offal . 

1. The feeding to the crusher will be always through an elevator unless offal waste is involved.
2. for special case of offal : use lamela pump for internal parts or legs , such pumps are sold by JS-PROPUTEC   https://jsproputec.com/ which is an excellent  manufacturer and well trusted
3. for the special case of offal feathers ,the feathers are sent with water at a ratio of 1:30  and a special water feather separator must be installed to reduce water content of the feathers before they enter the processing plant 
4. The crusher : crushers are not needed for  treatment  of offal as they are small enough for pumping and steam treatment ,how ever , in some countries it is common to freeze legs for 24 hours before they are sent for rendering process, in such cases,it is advisable to use a small crushing device . 
5. for primary and secondary  size reduction of cow  or pigs or sheep there are many manufacturers all over the world . it is advisable to buy a meat crushing machine only from local manufacturer as it is require a lot of maintenance operation and spare parts 
6. for USA : ANCO in north carolina is an excellent choice , https://ancoeas.com/en/ , They can slso provide other solutions for rendering ( see picture ) 
7. For Europe :: MONTS in  Hradec Králové, Czech Republic  is very trusted and good choice for installations made in west and east europe or Russia.  https://monts.cz/en/about-us.html
8. Unloading and Transfer of size reduced meat is always advisable with Lamela pump . The most common and reliable pump will always be from JSPROPUTEC which can also provide solutions such  as elevators and special feeders to lamela pumps https://jsproputec.com/

 Rendering of  Meat  or nay other by -product  must use a sterilization step in order to destroy pathogens and prepare the meat for a stabilized drying process . some manufacturers use cooking technology only, in big batch reactors under long treatment time and low temperature  for cooking operations. other manufacturers are using Batch reactors with short batch time under high temperature and pressure . some of this reactors are combined hydrolysis-size reduction reactor which enable good  stability for further separation operations .  The average Batch time in a combined Hydrolysis /sterilization/size reduction will be between 60 minutes for offal and 70 minutes for beef , this time include loading , hydrolyzing at 143 deg and crushing at very high RPM with a special rotating knife at the Bottom of the reactor . the Most common exit temperature will be 99 degree at 1.2 Bar . this temperature allows further separation by Decanter much more efficient then cooking vessels . The transfer of the Liquid Meat can be done by Pressure or by a pump as in the case of BSF treatment . Usually, The liquid is stored in a Balance tank before pumping for Drying. 

suppliers for combined histolysis /size reduction process : 

1. celitron in hungary - www.celitron.com
2. for reactor and balance tank only - MGT in israel www.mgt.co.il  

 some rendering plants will have a multi function operation which allow them 2 main options:

1. collecting the sterilized liquid as it is  and transfer it as additional biomass to  anaerobic digestors , a common  COD of 1 M3 of the hydrolyzed meat can vary from 60 to 100 Kg . it must be noted how ever that mixing of meat stream with regular population of the bioreactor might Couse inhibition  of the overall digestion process and there for it should be added carefully with loading not much then 10% of the over all COD fed into the digestor .  The common values for such Liquid will contain 9-12% protein , 7-9 % oil and fat and minerals . the over all solids can be as high as 20-25% solids and fats. 
2. Drying the liquid to form dry material with nutritional values for feeding animals /composting
3. Separating of Fat and polishing it to highest purity as nutrient or supplement s for feeding meals. 

• Primary Separation  - The liquid is fed by pump to Decanter or Tricanter or Filter press 
• The Outcomes (products) from the decanter are in the case of DECANTER - Solids -Water / Fat-water and in Case of TRI-CANTER : Solid water /Fat / Water 
• typical values (depend on  the products ) from  TRICANTER are  on the solid side 35-42% solids on the oil side 95-99 % Fat . Water would have less then 1000 PPM solid and Fat and can be accumulated also to Bioreactor or regular WWWTP at less then COD 4000. 

 After  Mechanical separation The rest of the water can be removed by several methods . :

1. Paddle dryer by using hot air to remove humidity . The size of the Paddle dryer varies according to the capacity and humidity of the material from the Decanter but as rule of thumb , The area of the drying zone should be 10-11 times the amount of water to be removed . 

Example : 1000 Kg with 60 % moisture is fed to dry to 10 % then the amount of water is 500 Kg  evaporated  and the size of the Paddle dryer varies between 50-60 sq.Meter . 

Example : same amount of water to remove 500 kg with specific heat =  2260 kj/kg  will need theoretically

314 KW-HR and in practice with thermal efficiency 88% close to 350 KW-Hr heat source .  

• Composting - Composting is currently the Only option for Rendering of cow meat in countries where it not allowed to use Protein for food source to other animals . 

If you need Assistance or Re design of your rendering plant don't hesitate to call or send an e-mail  

• tomer@renderingnews.com
• Phone:+972-544828001