Slaughtering 13 2 Process · processing into products such as pharmaceutical preparations. The blood water (or "serum" remaining after coagulation) may be evaporated for animal feed,

SECTION 13

Waste Reduction Resources for

Slaughter Houses and Meat Packing ... Page

1. industry Overview ........................................ .13 - 2

A. Slaughtering .......................................... 13 - 2 B. Meat Processing ...................................... .13 - 6 C. Process Flow for Slaughtering ............................ . I 3 - 7

Wastewater Characteristics .................................. 13 - 8

A. Summary of raw Waste Characteristics ...................... 13 -11 B. Sources of Wastewater

1. Animal pens ........................................ 13 -15 2. Slaughtering ....................................... .13 -15 3. Meat Processing ..................................... 13 -16 4. Clean-up .......................................... 13 -19

13 -20

11.

J'

111. Waste Reduction Tips for Slaughter and Meat Packing Operations ,., ( .. 'i I " 't !

. . . . . , .

,. .. . , . . . .

MEAT SPNOFF/INDUSTRY DESCRPT & PLANT SCHEME

I N D U S T R Y D E S C R I P T I O N A N D T Y P I C A L P L A N T S C i i E M E

I n d u s t r y D e s c r i p t i o n

Meatpacking plants carry out the slaughtering and processing of cattle, calves, hogs, and sheep for the preparation of meat products and by-products from these animals. those tha t carry out only one operation, such as slaughtering, t o fu l l - l ine plants t h a t not only slaughter, but also carry out processing t o varying degrees (manbfacturing of meat products such as sausage, cured hams, smoked products, etc.). some process only a portion of t he i r k i l l , while others process not only their k i l l , bu t also the k i l l from other plants. (packinghouses) and many slaughterhouses also render by-products; edible and inedible by-products are rendered from edible f a t s and trimmings and from inedible materials, respectively.

The plants in t h i s industry range from

/

The amount of processing varies considerably, because

Most fu l l - l ine plants

Manufacturing Processes

Stockyards and Pens A t most meatpacking p l a n t s , l ive animals s tay in holding pens fo r

less than one day prior t o slaughter. These pens are often covered t o o f f e r protection from the elements, and are sometimes enclosed. Wastewater resul ts from watering troughs, periodic washdown, and urine from the animals. waste load. downstream from any materials recovery processes, b u t before biological treatment.

Run-off from uncovered pens can also contribute t o the These wastewaters are usually contained and enter the sewer

Slaughtering Slaughtering animals includes ki l l ing (stunning, sticking -- cutting

the jugular vein, bleeding) and hide removal for ca t t l e , calves and sheep, and dehairing for hogs; eviscerating; washing the carcasses, and cooling. Many plants include processing blood, viscera, and hides as sub-processes. However, a l l plants d o n ' t perform a l l operations; f o r example, some plants ship out blood, hides, and viscera f o r processing elsewhere.

13 - 2


Animals taken from the pens are immobilized upon enter ing the k i l l

area by chemical, mechanical o r e l e c t r i c a l means. suspended by a hind l e g from overhead f o r s t i ck ing and bleeding. I tmob i l i zed hogs are hung over a bleeding trough o r placed on a conveyor with t h e f r heads hanging over the bleeding trough. During bleeding, the conveyor car ry ing the animal mves slowly over the trough o r gu t te r t h a t catches the blood so i t can be co l lec ted f o r blood processing.

lambs, and calves are genera l ly handled l i k e c a t t l e , splashes outside the c o l l e c t i n g area, espec ia l l y as the carcasses are

conveyed t o the next operation. ab le amounts o f blood i n t o the sewer.

mechanical means.

f o r skinning and at taching the hide pu l l e r . hand.

blood splashes on the wal ls, Much i s co l lected, but some reaches the sewer, p a r t i c u l a r l y dur ing clean-up.

Hogs are usua l ly not skinned, but are passed through a scalding tank o f water a t about 130°F, then dehaired.

so ld f o r uses such as the manufacture o f natura l b r i s t l e brushes, and fo r f u r n i t u r e s tuf f ing.

animal feed. Following dehairing, hog carcasses are singed f o r f i n a l h a i r removal, and sprayed w i th water t o cool and wash. They are inspected and trimmed t o remove any remaining h a i r o r other flaws. Scald water and dehai r ing and washwater conta in ha i r , s o i l and manure. The f i n a l carcass washwater i s r e l a t i v e l y clean. A l l o f t h i s water i s discharged t o the sewer.

A method i s developing f o r skinning hogs which i s s i m i l a r t o tha t used f o r skinning ca t t l e . dehair ing processes.

eviscerated. The heart, l i v e r , tongue ( c a t t l e ) , and kidneys a r e removed from the viscera and washed; these are so ld as edib le meat or are used i n

meat products. viscera i s channeled t o the v iscera handl ing subprocess. also trimmed and inspected.

Stunned c a t t l e are

Sheep. Sane blood s p i l l s o r

Clean-up operations also wash consider-

Fol lowing bleeding, the hides are removed from the ca t t l e , usua l l y by A t r a v e l i n g cage places the operator a t the proper l eve l

Very small p lants sk in by Some blood and t i ssue f a l l s t o the f l o o r dur ing t h i s operation, and

The h a i r i s sometimes baled and

Occasionally, it i s hydrolyzed and dr ied f o r use i n

Often i t i s disposed o f as s o l i d waste.

This method would e l iminate the scalding and

Next, the carcass i s opened by hand knives and the animal i s

Lungs may be sold f o r pet food. The balance o f the The carcass i s

Scrap trimmings go t o rendering f o r ed ib le o r

13 - 3


i n e d i b l e by-products. Blood and t i ssue from t h e eviscerat ion f i n d t h e i r

way d i r e c t l y t o t h e sewer and are washed i n t o the sewer during clean-up. The carcasses, cut i n h a l f f o r beef and hogs, and l e f t whole f o r sheep and

calves, are hung i n a cooler where they stay a t l eas t 24 hours. Mater ia ls recovered dur ing clean-up, p a r t i c u l a r l y by dry clean-up procedures, go t o Inedible rendering, e i t h e r on- o r o f f -s i te .

B lood Processing

house operation. However, i n some cases, the blood may be shipped out o f a p l a n t f o r processing elsewhere. t h e albumin; then t h e albumin and f i b r i n are separated (such as w i t h a screen o r cent r i fuge) from t h e blood water and forwarded f o r f u r t h e r

processing i n t o products such as pharmaceutical preparations. The blood water (or "serum" remaining a f t e r coagulat ion) may be evaporated fo r animal feed, or i t may be sewered. d i rec t l y t o conventional b lood dryers and used f o r animal feed.

Handling and processing the blood i s usua l l y a pa r t o f the slaughter-

The blood may be heated t o coagulate

I n m s t cases, the whole blood i s sent

Viscera Handling

t h e contents o f the paunches, 50 t o 70 pounds o f p a r t i a l l y digested feed ("paunch manure") are washed out w i t h water and passed over a screen. separated so l i ds go t o s o l i d waste handling. The l i q u o r passing through

t h e screen i s general ly sewered. I n dry handling, paunch contents are

dumped on a screen o r other dewatering device and the so l i ds are sent

e i t h e r t o a dryer or t o a t ruck f o r removal from the plant.

p lants , t h e e n t i r e paunch contents are sewered; s o l i d s are l a t e r removed a t

t h e sewage treatment plant. paunches.

f o r ed ib le products. new p rac t i ce i s t o send t h e e n t i r e contents t o processing o r t o haul out

f o r disposal elsewhere.

and washed and then sent t o rendering.

stomachs and in tes t i nes are washed and saved f o r ed ib le products.

The beef paunches may be handled e i t h e r wet o r dry. For wet handling,

The

I n some

It i s a lso common t o scald and bleach the

The paunches are then washed thoroughly i f they are t o be used A Hog stomach contents are normally wet processed.

The in tes t i nes may be sent d i r e c t l y t o rendering o r they my be hashed Often, the beef paunches, hog

13 - 4

..... " . .

I


For example, i t i s c m o n t o bleach the paunches f o r marketing as

tripe, and t o recover hog casings and c h i t t e r l i n g s ( la rge in tes t ines of hogs). Occasionally, paunches and stomachs are given only a b r i e f washing

and a re so ld as mink o r pet food. Stomachs may be sent, unopened, d i r e c t l y

t o i ned ib le rendering. Hog in tes t ines s t i l l f i n d some market as sausage casings and f o r surg ica l sutures. Any viscera washing o r c leaning r e s u l t s I n the contents of stomachs, intest ines, etc., and a considerable amount of grease being discharged t o the sewer.

Hide Processing

demanurfng, washing, and defleshing, fo l lowed by a b r i ne cure i n a b r ine va t or raceway. The cure time may be as short as 12 hours. I n dry curing,

t h e washed, defleshed hides are packed with s a l t and stacked i n the cur ing room. Often hides are only sa l ted and hauled t o other p lants o r t o tanner- ies f o r washing, def lesh ing and curing. Washing may be done by batches i n a r o t a t i n g screen, o r i n a tumbler s i m i l a r t o a la rge concrete mixer. De-

f l esh ing i s usua l ly done by passing the h ide through r o t a t i n g scraper knfves. befng made toward t rans fe r r i ng some o f the tannery operations t o the

s laughter ing p lant ; t h i s allows ensuing wastes t o be channeled i n t o aniaml

feed. On the o ther hand, some specia l ty p lants have come i n t o being t h a t

take the green, unwashed hides from the slaughter ing operat ion and deflesh,

clean, and cure them as an intermediate step before they go t o the tannery. Hide processing leads t o s ign i f i can t loads o f blood, t issue, and d i r t being sewered. wastewater.

Hides may be processed wet o r dry. Wet processing involves h ide

[- / I n very small p lan ts both may be done by hand. Some e f f o r t i s

The cur ing operat ion contr ibutes s a l t (sodium chlor ide) t o the

Cu t t i ng

and i s o f ten performed i n a separate par t o f the bui ld ing.

ca r r i ed out i n p lants tha t do no fu r ther processing. p a r t i c u l a r l y t rue i n the case o f beef plants.

carcasses are c u t e i t h e r f o r d i r e c t marketing o f smaller sections or i nd i v idua l cuts, or for fu r ther processing i n the processing operations. Trimmings from t h i s operat ion tha t do not go i n t o products such as

Meat c u t t i n g may be considered par t o f the "processing Operation", It also may be

The l a t t e r i s I n the cu t t i ng area, the

13 - 5

MEAT SPNOFF/INOUSTRY OESCRPT & PLANT SCHEME .i

sausages and canned meats, go t o rendering o f ed ib le f a t s and tal lows.

I n e d i b l e mater ia ls are rendered f o r i ned ib le f a t s and sol ids. There i s

always some mater ia l t h a t reaches the f l o o r , and a considerable amount t h a t adheres t o saw blades o r conveyor systems. dust, f a t t issues, and blood t h a t can be recovered f o r i ned ib le rendering. Much o f t h i s , however, i s washed t o the sewer dur ing cleanup.

This includes meat, bone

Heat Processing The ed ib le po r t i on r e s u l t i n g frm slaughter ing and c u t t i n g may be

processed i n a va r ie t y o f ways. These include manufacturing many v a r i e t i e s

o f sausages, hams, bacon, canned meats, p ick led meats, hamburger, por t ional cuts, etc. Processing ed ib le products i s complex and var ies from p lan t t o p lant . corned beef. Hog carcasses are cut up and hams, sides, and shoulders are genera l ly sent t o curing.

such as Canadian bacon; most l o i n s are packaged without cur ing f o r t h e r e t a i l market.

a r e obtained from processing 1000 kg LWK ( l i v e weight k i l l e d ) i n meat processing operations.

hog operations. But when edib le rendered products such as lard, and f resh pork products such as l o i n s are excluded, the value i s reasonable.

Further, the value o f 400 kg processed product per 1000 kg LWK ( o r a r a t i o o f processed products t o LWK o f 0.4) forms a natural break po in t i n

ca tegor i z ing packinghouses. low-processing packinghouses; high-processing packinghouses have a r a t i o o f

a t l e a s t 0.4. The cu r ing operation involves i n j e c t i n g a s a l t and sugar so lu t i on

i n t o t h e meat, usual ly with a mult ineedle i n j e c t i o n machine. Some cur ing i s done by soaking the meat i n a cur ing solut ion. Smoking i s achieved i n

smokehouses operated a t elevated temperatures. obtained by soaking meat i n a " l i q u i d smoke" solut ion; i n j e c t i n g t h i s

s o l u t i o n i n t o t h e meat w i l l a lso r e s u l t i n a smoked f lavor . S p i l l s frm cooking equipment, cure so lut ion s p i l l s during i n jec t i on , and p a r t i c l e s sewered dur ing clean-up a l l cont r ibute t o the waste load.

Some beef cuts are del ivered t o cur ing rooms f o r preparat ion o f

Some l o i n s may be deboned and cured f o r products

An average o f about 400 kg o f ed ib le "processed" products

This number can vary and may be much higher i n some

Products t o LWK r a t i o s o f less than 0.4 a r e

Smoked f l a v o r s are a lso

13 - 6

c> MEAT SPNOFF/INDUSTRY DESCRPT & PLANT SCHEME

Livestock Pens

Ki I ling

1 I--

Hide Removal

Hog Oehairing

Eviscerating Minor By-product Processing

Trimming

to > Outside

Processing

Cooling Carcasses I I

Figure 3. Process Flow for Slaughterhouse

13 - 7

MEAT SPNOFF/WW CHARACTERIZATION

b i

Wastewater Character is t ics

Water i s a raw mater ia l i n the meat packing i , idust ry tha t i s used t o cleanse products and t o remove and convey unwanted mater ia l . The pr inc ipa l

operations and processes i n meat packing p lants where wastewater o r ig ina tes

are: Animal holding pens

S1 aughter i ng Cut t ing

Meat processing Secondary manufacturing (by-product operations) inc lud ing

Ed ib le and ined ib le rendering

Clean-up Wastewaters from slaughterhouses and packinghouses contain organic matter ( inc lud ing grease), suspended sol ids, and inorganic mater ia l such as

phosphates, n i t ra tes , n i t r i t e s , and sa l t .

stream as:

These mater ia ls enter the waste

blood meat and fa t ty t i sue

meat ex t rac ts

paunch contents bedding

manure h a i r d i r t contaminated cool ing water losses from rendering

cur ing and p i c k l i n g so lut ions

preservat ives

caus t ic o r a l ka l i ne detergents.

Raw Waste Charac ter is t i cs

The r a w waste load from the indus t ry 's four categories excludes the by-products gleaned from in-p lant recoveries.

b i rds w i th one stone" by reclaiming by-products which would otherwise be sent t o the w a s t e s t r e a m s and subsequently requi re treatment as

po l lu tants .

These recoveries " k i l l two

13 - 8


One EPA study o f the indust ry analyzed 85 plants. Much of the f o l - lowing discussion i s based on the data gathered dur ing tha t study. parameters used t o character ize the raw e f f l u e n t were the flow, BOO,

suspended so l i ds (SS), grease, chlorides, phosphorus, and Kje ldahl n i t r o - gen. BOD was considered t o be. i n general, the best avai lab le measure o f

t he waste load. Parameters used t o character ize the s ize o f the operations were the k i l l ( l i v e weight) and volume o f processed meat products produced. All values o f waste parameters are expressed as kg/1000 kg/LWK, which has the same numerical value when expressed i n lb/1000 l b LWK. I n sane cases the e f f l u e n t s were so d i l u t e tha t the concentration became l i m i t i n g . these cases, concentrat ion was expressed as mg/l.

processed meat products are expressed i n thousands o f kg. Tables 4 through 7 inc lude a data sumnary showing averages, standard deviat ions, ranges, and

number o f observations (p lants) f o r each o f the four indust ry categories.

The

I n K i l l and amount o f

S1 aughterhouses

both simple and complex slaughterhouses i s shown i n Figure 4. simple slaughterhouse normally conducts very few o f the by-product

operations (secondary processes) l i s t e d i n Figure 4, whereas a complex slaughterhouse conducts mst o r a l l o f them. Occasionally slaughterhouses

may not have wastewaters from some o f the operations shown, depending upon Ind i v idua l p lan t circumstances. For example, some slaughterhouses have

dry animal pen clean-up w i th no discharge o f wastewater, some have l i t t l e o r no cu t t ing , and others may have a separate sewer f o r sani tary waste.

No d i s t i n c t i o n was made i n the categories f o r the type of animal being

slaughtered. I t i s recognized, however, t ha t i n some small p lants there w i l l be more s i g n i f i c a n t differences i n p o l l u t i o n waste loads depending on the animal type. These cases, however, are s t i l l w i t h i n the waste loads c i t e d f o r the subcategory.

waste charac ter is t i cs f o r a simple slaughterhouse. The tab le shows tha t

24 of the 85 p lan ts analyzed were simple slaughterhouses (about one-half were beef and the others d iv ided between hogs and mixed k i l l ) and tha t the

A t y p i c a l f low diagram i l l u s t r a t i n g the sources o f wastewaters i n

Note tha t a

The f l ow diagrams lnclude both beef and hog operations.

Simple Slaughterhouses. Table 4 sumarizes the p lant and raw

if.-

13 - 9


i .

Sanitary Facilities

R a v ' Wastevater

Slaughterhouse -+ from

Figure 4. Operating and Wastewater Flow C h a r t f o r Simple and Complex Slaughterhouses.

13 - 10

...I

fable 4. Sumnary o f P l a n t and Raw Waste Characterlstlcs for Simple Slaughterhouses.

llw K i l l BOD5 1/1000 k t kg/lOOO ka

Base LWK 1000 kglday LWK

(Number of P l a n t i ) (24) ( 2 4 ) (24)

Average 5.328 220 6.0

S t a n d a r d Deviation 1,644 115 1.0

Range, l o r h i g h 1,134- 18.5- 1.5- 14,641 5 5 2 . 14.1

K i l l ' BOD5

Xjaldahl T o t a l Suepmdcd N i r r o t m Chlotld*n ?hotphorua

Solid. a. n a t Cl a t P

Kj c l d a h l Suapcnded Nitrogen

SolidB cceaac a t N

:S: I 2.1 1 0.68 1 , ::: 1 . 0.05 I 0.6- 0.24- 0.23- 0.01- 0.014-

2 .2 0.46 0.03

12.9 7.0 1.16 S. h 0.086

1000 kglday

Table 5. Sumnary o f P lant and Raw Waste Characteristics f o r Canplex Slaughterhouses.

kg/lOOO kg kg/lOOO kg kg/lOOO kg kg/lOOO kg LVK LWX LUX LWK Ba,?lc

Number of P l a n r a )

Average

(19)

595

.. l l o v

1/1000 kg LWX

(19)

7,179

(19)

10.9

Standard Devinrienl 2,718 I 156 I h . 5 I 4.1 I 5.7 I 0.66

0.13- 2.8- I 0.7- I I 12,507 20.5 16.8 2.1 1,627- Range, low-high

Total

2.8 0.33

2.7 0.49

I 7.9 I 1.2 0.01- 0.05-

Table 6. Sumnary o f Plant and Raw Waste Character is t ics f o r Low-Processing Packinghouses.

A w

A N

Table 7. Sumnary o f Plant and Raw Waste Characteristics for High-Processing Packinghouses. 2

F 8.1 0.91 11.3 0.11 166

2.8- 0.65- 0.1- 9.2- 4.5- 0.43- 0 I m

N

21.0 2 . 1 36 .1 0.61 e l l . 2.14 T: 3 H 0 z

.. , , ...,

i


?> It,. BOD waste load covered a range from 1.5 t o 14.3 kg/1000 kg LWK (same value

i n lb/1000 l b LWK). Small p lants were determined as those w i th a LWK of l ess than 43.130 kg (95,000 lbs) , and medium p lan ts as those w i th a LWK

between 43,130 kg and 344,132 kg (758.000 l b ) . Two of the 24 p lan ts were small and the remainder were medium-sized.

Complex Slaughterhouses. Table 5 sumnarizes the p lan t and raw

waste charac ter is t i cs f o r canplex slaughterhouses.

p lan ts analyzed were canplex slaughterhouses (11 were beef; 6 hogs; and 2, mixed). Def in ing a large p lant as one w i t h a LWK o f greater than 344.132

kg (758.000 lb ) , and a medium p lan t as i n the paragraph above, Table 5 k i l l data show a l l canplex slaughterhouses included were e i t h e r medium o r large. Ac tua l l y about one-third *re large.

Nineteen of the 85

Packinghouses A t y p i c a l flow diagram i l l u s t r a t i n g the sources o f wastewaters i n

r: both low- and high-processing packinghouses i s shown i n Figure 5. Remem- ber t h a t the main d i f fe rence between a low- and high-processing packing-

house i s the amount o f processed products r e l a t i v e t o k i l l ; i.e., a r a t i o o f less than 0.4 f o r a low- and greater than 0.4 f o r a high-processing

plant. f o r a low-processing packinghouse.

processes and operations cont r ibu t ing t o the waste load as a slaughterhouse, plus the meat processing steps f o r the packinghouse.

d i f fe rence i s t ha t the degree and amount o f c u t t i n g i s much greater f o r a packinghouse. I n some cases, unf in ished products may be shipped from one

p lan t t o another f o r processing, resu l t i ng i n more products produced at a p lan t than l i v e weight k i l l e d there.

raw waste charac ter is t i cs for low-processing packinghouses. Twenty-three

o f the 85 p lan ts analyzed were low-processing packinghouses. The average r a t i o o f processed products t o k i l l i n these 23 p lan ts was 0.14, w i th a standard dev ia t ion o f 0.09. The low-processing packinghouses included i n the analyses have a r a t i o of processed products t o LWK wel l below the

value o f 0.4 used t o d is t ingu ish between low- and high-processing plants. Using the above d e f i n i t i o n s o f p lant size, the k i l l data show that a l l the

packing houses i n the sample were medium or large i n size.

As a resu l t , the waste load con t r i bu t i on from processing i s less A packinghouse has the same basic

Another

Low-Processing Packinghouses. Table 6 sumnarizes the p lant and

13 - 1 1

MEAT SPNOFF/WW CHARACTERIZATION ,'

H.tcr1.1.

f3- Recovery

Slaughtering

C"Ci"S c.nn1ng

Figure 5. Operating and Wastewater Flow Chart for Low- and High- Processing Packinghouses.

13 - 14


5 Sources o f Wastewater

Anlmal Pens. Although pen wastes only contain about 0.25 kg o f BOD/lOOO kg LWK, these wastes are high in nutr ients.

s o l i d wastes are removed by dry cleaning, followed by l i t t l e o r no

washdown.

recover so l i ds ra the r than a l lowing them t o enter a treatment system. Any

r a i n f a l l o r snome l t run-of f i s normally contained and routed f o r treatment with o ther raw waste flows. Watering troughs are another source o f pen wastewater. more. With 50 o r m r e pens used a t a la rge plant, the water source becomes s ign i f i can t .

p lant , pen waste i s but a minor contr ibutor . Slaughtering. The slaughter ing operation i s the la rges t s ing le

source of waste load i n a meat packing plant, and blood i s t he major cont r ibutor . Blood i s r i c h i n BOO, chlorides, and nitrogen. It has an

u l t ima te BOD of 405,DOO mg/l and a BOO5 between 150,000 and 200,000

mg/l. Ca t t l e conta in up t o 50 pounds o f blood per animal, and t y p i c a l l y on ly 35 pounds o f the blood are recovered i n the s t i c k i n g and bleeding area. The remaining 15 pounds o f blood are l o s t as wastes which represents

a waste load o f 2.25 t o 3.0 kg B00/1000 k g LWK (2.25 t o 3.0 lb/1000 l b LWK). Total loss o f the blood represents a po ten t ia l BOD waste load of 7.4 t o 15 kg/1000 kg LWK (7.5 t o 15 lb/1000 l b LWK). Because very few meat p lan ts p rac t ice blood contro l outs ide o f the bleeding area, the t yp i ca l BOD

load from blood losses i n the s laughter ing operation i s estimated t o be 3 kg/1000 kg LWK.

removal. Beef paunch o r rumen contents i s another major source o f waste.

Paunch manure, which contains p a r t i a l l y digested feed mater ia l , has a BOO o f 50.000 mg/l. Of the e n t i r e contents can cont r ibu te 2.5 kg/1000 kg LWK.

comnon pract ices are t o e i t h e r screen the paunch contents, washing the so l i ds on the screen (wet dumping), o r t o dump on a screen t o recover the

sol ids, a l lowing only the " j u i ce " t o run t o the sewer (dry dumping). Because 60 t o 80 percent o f the BOD5 i n the paunch i s w a t e r soluble,

w e t dumping o f the paunch represents a BOD5 loss o f about 1.5 kg/1000 kg LWK.

less than th i s .

Frequently, the

I f washdown i s practiced, a manure t r a p i s f requent ly used t o

Each trough may discharge 8 l /m in (2.1 gal/min) o r

However, considering the t o t a l waste load from the

f-

I n beef plants, much of t h i s loss occurs dur ing hide

A t an average paunch weight o f 50 pounds per head, dumping However, the

I f dry dumping i s pract iced, the po l l u t i ona l waste load i s much When none of the paunch i s sewered but is processed or

13 - 15

MEAT SPNOFF/WW CHARACTERIZATION i

hauled out of the plant for land disposal, paunch handling does not contribute t o the waste load. i s a hot a lkal ine solution ( t r ipe processing) will add t o the waste load, par t icular ly t o the grease load. waters my also make grease recovery mre d i f f i cu l t .

pollution. The overflow from a hog scald tank i s usually about 84 1/1000 k g LWK (10 ga1/1000 l b LWK) a t a BOD loss of about 3000 mg/l. T h i s could represent a BOD loss of about 0.25 kg/1000 kg LWK. Continuous overlow of water from the dehairing machine is estimated t o contribute a maximum BOD5 load of 0.4 kg/1000 kg LWK.

washing, viscera and offal processing, and stomach and neck f l u s h i n g . The offal operations such as ch i t te r l ing washing and cleaning intestinal casings can also contribute t o the waste load.

Nevertheless, cooking of the rumen or paunch

The strong alkal ini ty of these waste-

The hog scald tank and dehairing machine a re other sources of

Other wastes from slaughtering and carcass dressing are from carcass

The waste contribution from these operations could be greatly reduced i f the slime waste from the casings was not sewered.

Of carcasses; an extreme example for which data are available shows rates o f 2915 l / m i n (350 gal/min). viscera, conveyor s t e r i l i z ing , and the t r i p e "umbrella" washer are other h i g h water use operations.

Heat Processing. meat ex t rac ts , meat and f a t ty t issue, and curing and pickling solutions. Loss of these solutions can be the major contributor t o the waste load from processing. the curing brine remained i n the product. t o the sewer. curing and sa l t ing floors t o reduce slipperiness, explains why some packinghouse wastes are h i g h in chlorides. i s dextrose; i t has a BOD equivalent of 0.66 kg /kg ( lb/ lb) . packinghouses w i t h a sizeable curing f a c i l i t y will have a h i g h BOO waste unless the wastes from curing are segregated or recycled. over 2000 pounds of dextrose was los t daily. and f a t t y t i s sue can be substantially reduced by dry clean-up prior t o

The highest source of water use i n slaughtering i s from the washing

F l u s h i n g the manure from chi t te r l ing and

The major pollutants from m a t processing are

The results of a recent study showed tha t only 25 percent of The res t of the brine was los t

T h i s source of chlorides, plus others such as from hide

Another constituent of the cure Consequently,

I n one plant The pollution load from meat

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f washdown. The water use i n meat processing should be p r imar i l y l i m i t e d t o

cleanup operations and t o product washing, cooling, and cooking.

Secondary Manufacturing Processes

within the indus t ry f o r the handling, recovery, and processing o f blood, t r lm lngs , .and ined ib le o f fa l . They include paunch and viscera handling,

h lde processing, h a i r recovery and processing, and edib le and ined ib le renderlng. Those viscera and o f f a l operations t h a t occur on the slaugh- t e r i n g f loor , such as paunch handling and t r i p e processing, were considered under slaughtering.

rendering, produces a strong waste load w i th a BOO value o f about 70,000

mg/l. The waste conservation t rend i n the past few years has been toward n o t hashing and washing p r i o r t o rendering, but sending the uncleaned

v l t c e r a d i r e c t l y twrender ing. I n one plant, removal o f the hasher and washer reduced the BOO by 910 kg (2000 pounds) per day, w i th an attendant

increase i n the rendered animal feed production. E f f i c i e n t recovery o f hog h a i r i s now pract iced widely w i t h i n the

industry, although the market f o r t h i s by-product has been reduced i n recent years. Very few p lan ts hydrolyze hog hai r , but ra ther wash and

b a l l i t f o r sale o r disposal d i r e c t l y t o land fi l l. Hide cur ing operations are becoming increasingly involved a t meat

packing plants. i n tanks, vats, o r raceways. The hides, p r i o r t o being soaked i n brine,

a re washed and defleshed. These washings, which are sewered, contain blood, d i r t , manure, and f lesh. I n most def leshing operations the bulk o f

the t i ssue i s recovered. I n add i t ion t o these wastes, soaking the hide i n the br ine resu l t s i n a net overf low o f approximately 7.7 l i t e r s (2 ga l lons)

of b r ine so lu t ion per hide. I n a few p lants the br ine i n the raceway i s dumped weekly. I n others i t i s dumped yea r l y or whenever the so l ids b u i l d

Secondary manufacturing processes are those by-product operations

The hashing and washing o f viscera, o f ten performed p r i o r t o

(t

Today many beef s laughter operations include hide cur ing

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up t o a po int where they i n t e r f e r e w i th the hide cur ing operation. l i f e of the br ine can be extended by pumping the recycled br ine over a

v ib ra t i ng o r s t a t i c screen.

The

The waste load f ran the overflow and washings, i n a typ ica l h ide cur ing operation, where the hide cur ing wastes are not .d % c

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f requent ly dumped, i s about 1.5 kg/1000 kg LWK f o r BOD and about 4 k g

salt/1000 kg LWK.

which are q u i t e comnon, use a jacketed vessel wi th r o t a t i n g blades t o prevent burn-on; t h i s process resu l t s i n low losses t o the sewer (es t i -

mated t o con t r i bu te about 0.3 kg BOD/1000 k g LWK). Continuous r i n g dryers a re sometimes used; they produce a r e l a t i v e l y small amount o f blood water

that , i n some small plants, i s discharged t o t h e sewer. The ho ld technique

of steam sparging t h e blood t o coagulate it i s s t i l l f requent ly used. The

coagulated blood i s separated from the blood water by screening. The blood water has a BOD of about 30,000 mg/l. It i s o f ten sewered, con t r i bu t i ng a waste load o f about 1.3 kg/1000 kg LWK. This loss can be el iminated by evaporating the blood water, e i t h e r by i t s e l f o r by canbining i t with o the r

ma te r ia l s i n conventional i ned ib le dry rendering operations. Wet rendering and low temperature rendering are p o t e n t i a l l y l a rge

sources o f po l l u t i on . Tank water from wet rendering can have a BOD value of 25,000 t o 45,000 mg/l, and the water centr i fuged from low temperature

rendeirng can have a BOD o f 30,000 t o 40,000 mg/l. It i s estimated t h a t sewering o f e i t h e r o f the waste streams produces a waste load o f 2 kg

BOD/1000 kg LWK. These waste loads can be el iminated by evaporation o r combining wi th other mater ia ls used i n dry inedib le rendering. T r ip le -

ef fect vacuum evaporators are o f ten used t o concentrate t h e "tankwater" from the wet rendering operation. The waste load from wet rendering i s

p r i m a r i l y caused by overf low o r foaming i n t o the b a r m e t r i c l eg o f these evaporators and discharge t o the sewer or, sometimes d i r e c t l y t o a stream.

From dry rendering t h e p o l l u t i o n cmes from the condensing vapors, from spi l lage, and from clean-up operations. A recent study revealed t h a t a

t y p i c a l dryer used 454 t o 492 l /m in (120 t o 130 gal/min) o f water f o r condensing vapors, and t h a t the e f f l u e n t contained 118 mg/l o f BOD and 27 mg/l grease. The estimated waste load from dry rendering i s 0.5 kg/1000 kg LWK.

Blood processing may be done e i t h e r wet o r dry. Continuous dryers,

Cutt ing. The main p o l l u t a n t s from c u t t i n g operations are meat and f a t scraps from trimming, and bone dust from sawing.

po l l u tan ts enter the waste stream dur ing clean-up operations. wastes can be reduced by removing the major i ty o f them by dry clean-up

p r i o r t o washdown, and also, by some form of grease t rap i n c u t t l n g area.

Most o f these

These

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The co l lected mater ia l can be used d i r e c t l y i n rendering. Bone dust i s a i

la rge source o f phosphorus and when mixed wi th water, does not s e t t l e out readi ly; thus It i s d i f f i c u l t t o recover, and should be captured i n a box

under the saw. Clean-up. Clean-up contr ibutes between 0.3 and 3 kg BOO/1000 kg

LMK i n small packinghouses. Data co l lected by the Iowa Department o f Environmental Q u a l i t y showed tha t anywhere from 27 t o 56 percent o f the t o t a l BOD waste load i s contained i n the clean-up wastewaters. The clean-up operation i s a major cont r ibutor t o the waste load. t o a s ign l f i can t loss o f recoverable by-products. Detergents used i n clean-up can adversely a f fec t the e f f i c iency o f grease recovery i n the p lan t catch basin.

The techniques and procedures used during clean-up can grea t ly

inf luence the water use i n a p lant and the t o t a l po l lu t iona l waste load. For example, dry cleaning o f f l oo rs p r i o r t o wash down t o remove scraps,

and dry scraping o f - t h e blood from the bleed area i n t o the blood serrer are f i r s t steps. A l i g h t washdown, draining t o the blood sewer before the

It also leads

. normal washdown, d e f i n i t e l y decreases the po l l u t i on load from clean-up.

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JVASTE REDUCTION TIPS FOR SLAUGHTER AND MEAT PACKING OPERATIONS

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Train employees on dry clean-up techniques. Dry clean-up focuses on removing as much waste as possible from the floors and equipment (including equipment that must be disassembled for cleaning) prior to beginning wet clean-up.

Provide brushes, squeegees, shovels, additional catch pans, and training on dry clean-up methods. Solids can be shoveled before using water. Look for squeegees that can be used to clean troughs, using brooms on blood and other wet materials is not as effective. Additionally, shop vacs are good tools for both wet and dry clean-up. You may even consider putting covers over the drains until a good dry clean up can be done, then removing the covers to wash down with water.

Use catch pans or troughs to catch all blood, fat, and solids before they reach the drains. Catch pans should be deep enough so that they do not overflow and should be emptied before they overflow or before water is used in clean-up. Areas where pans or troughs are needed include; kill areas, singers, cut areas, hoggers, chit washing and packing areas, grinders, salting operations, and all process areas where fats, solids, and brines can be collected.

Look for ways to capture oil and grease drippings from smoke house floors or other cooking areas. You might be able to squeegee the oil into a container and/or use an absorbent.

Consider hiring someone full time to do dry clean-up during processing. This helps to keep pieces off of the floor and also cuts down on the amount of fat, blood, etc. being tracked through the facility.

Strainer baskets should be installed in all drains. Make sure employees do not remove these baskets or slant grates during clean-up to get big pieces of solids down the drains.

Clean solids out of grates and pens in animal barns before washing with high pressure hoses.

Animals should be properly aligned when they are killed so that blood flows into the troughs and not on the floor.

Extend blood troughs all the way to the prewash or use catch pans at the end of the troughs. Look for areas where blood gets into floor drains before it can be cleaned up.

Install high pressure low volume nozzles on all hoses to reduce the amount of water used in cleaning.

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Make sure sterilizers are not overflowing and check to see if the flow on sterilizers can be reduced.

Check all handwashes for leaks at the base.

Use automated washing systems for washing hooks and tree racks. Any system used should have a strainer or screen to removed solids from the wash and rinse waters. Soaking or pre-washing the hooks and trees can reduce the amount of detergent and water required for cleaning.

An inspection of bathrooms and locker rooms should be conducted. Things to look for include running toilets, leaking showers, and leaking faucets.

All exterior faucets should be periodically checked to assure that they are not broken. Installing flow control valves in these faucets can reduce water usage by outside personnel.

A final plant walk through should be conducted after clean-up when the plant is going to be shut down (Le. weekends, holidays) to assure that all water lines are shut off.

Preventative maintenance schedules should be established for all equipment. If such a program requires additional maintenance personnel then additional personnel should be hired. Preventative maintenance not only reduces waste generation but prolongs equipment life and can improve safety.

Explore the possibility of separating out the effluent from the barns and the trailer wash areas for possible land application.

Use mini” amounts of water in mucosa cookers so that cook down is more complete and there is less discharge. Since this is a high ammonia stream consider adding this discharge to the effluents from the truck wash and stock yard wash for land application purposes.

Condensate from rendering is another high ammonia stream which could be isolated and perhaps added for land application. If high ammonia streams can be segregated you may be able to find someone that would be interested in using this waste stream in fertilizer. The city or county may even be interested in using it as a nitrogen supplement for composting.

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Documents

Slaughtering 13 2 Process · processing into products such as pharmaceutical preparations. The blood water (or "serum" remaining after coagulation) may be evaporated for animal feed,