C Dairy

Manure characteristics for lactating and dry cows and for heifers are listed in table 4-5. These data are appropriate for herds of moderate to high milk production. Quantities of dairy manure vary widely from small cows to large cows and between cows at low production and high production levels. Figure 4-1 more accurately reflects these quantities of "as excreted" manure total solids and volatile solids where more precise data are desired. Dairy feeding systems and equipment often allow considerable feed waste, which in most cases is added to the manure. Feed waste of 10 percent can result in an additional 40 percent of total solids in a dairy waste. Dairy cow stalls are often covered with bedding materials that improve animal comfort and cleanliness. Virtually all of the organic and inorganic bedding materials used for this purpose will eventually be pushed, kicked, and carried from the stalls and added to the manure. The characteristics of these bedding materials will be imparted to the manure. Quantities of bedding materials added to cow stalls and resting areas are shown in table 4-4. See 651.0403(b), "Foreign material in manure," for additional information.

Milking centers—the milk house, milking parlor, and holding area—can produce about 50 percent of the waste volume, but only about 15 percent of the total solids in a dairy enterprise (table 4-6). Because this very dilute wastewater has different characteristics than the waste from the cow yard, it is sometimes

Lagoons that receive a significant loading of manure, such as from the holding area or the cow feed yard, generally operate in an anaerobic mode (table 4-7). Supernatant (upper liquid layer of the lagoon) concentration in an anaerobic lagoon is much greater than that in an aerobic lagoon. Anaerobic dairy lagoon

Table 4-5 Dairy waste characterization — as excreted*

Component

Lactating

Dry

Heifer

Weight

lb/d/1000#

80.00

82.00

8S.00

Volume

ft3/d/1000#

1.30

1.30

1.30

Moisture

%

87.S0

88.40

89.30

TS

% w.b.

12.S0

11.60

10.70

lb/d/1000#

10.00

9.S0

9.14

VS

it

8.S0

8.10

7.77

FS

h

1.S0

1.40

1.37

COD

h

8.90

8.S0

8.30

BOD5

h

1.60

1.20

1.30

N

h

0.4S

0.36

0.31

P

h

0.07

0.0S

0.04

K

h

0.26

0.23

0.24

TDS

0.8S

C:N ratio

10

13

14

* Increase solids and nutrients by 4% for each 1% feed waste more than 5%.

* Increase solids and nutrients by 4% for each 1% feed waste more than 5%.

Chapter 4 Agricultural Waste Characteristics Part 651

Agricultural Waste Management Field Handbook sludge accumulates at a rate of about 0.073 cubic foot per pound of total solids added to the lagoon. This is equivalent to about 266 cubic feet per year for each 1,000 pound lactating cow equivalent (100% of waste placed in lagoon).

If a dairy waste lagoon receives wastewater only from the milk house or the milking parlor, the lagoon generally exhibits a very dilute supernatant and operates in an aerobic mode (table 4-7). The rate of sludge accumulation in such lagoons is slow.

Figure 4-1 allows a more specific estimation of dairy manure solids production based on lactating cow size and the level of milk production. The following examples show how this graph can be used.

Example 4-1: Estimate the daily production of total volatile and fixed solids in the manure of a 1,000 pound cow that is producing milk at the rate of 11,000 pounds per year.

Entering figure 4-1 on the horizontal scale at the annual milk production level of 11,000 pounds and projecting vertically to the TS and VS curves for the 1,000 pound cow and then horizontally to the vertical scale, the values of 8.9 lb/d and 7.6 lb/d are found for TS and VS, respectively. Fixed solids, which are determined by taking the difference between TS and VS, equal 1.3 lb/d (8.9 - 7.6).

Example 4-2: Estimate the daily production of total volatile and fixed solids in the manure of a herd of 125 cows of 1,400 pound average weight producing 19,200 pounds of milk per cow per year.

Entering figure 4-1 on the horizontal scale at the annual milk production level of 19,200 pounds and projecting vertically to the TS and VS curves for the 1,400 pound cow and then horizontally to the vertical scale, the values of 14.2 lb/d and 12.1 lb/d are found for TS and VS, respectively. Multiplying each of these values by 125, the number of cows in the herd, and determining FS from the difference of TS and VS, the daily manure solids produced by the herd are:

Table 4-6 Dairy waste characterization — milking center

Table 4-7

Dairy waste characterization — lagoon

Component

Units

MH MH+MP MH+MP+HA

Aerobic* Supernatant

MH MH+MP MH+MP+HA

Volume

ft3/d/1000#

0.22

0.60

1.40

1.60

Moisture

/

99.72

99.40

99.70

98.50

TS

/ w.b.

0.28

0.60

0.30

1.50

VS

lb/1000 gal

12.90

35.00

18.30

99.96

FS

it

10.60

15.00

6.70

24.99

COD

h

25.30

41.70

BOD

h

8.37

N

h

0.72

1.67

1.00

7.50

P

h

0.58

0.83

0.23

0.83

K

h

1.50

2.50

0.57

3.33

C:N ratio

10

12

10

7

MH - Milk house; MP - Milking parlor; HA - Holding area. Holding area scraped and flushed—manure excluded. Holding area scraped and flushed—manure included.

MH - Milk house; MP - Milking parlor; HA - Holding area. Holding area scraped and flushed—manure excluded. Holding area scraped and flushed—manure included.

Aerobic* Supernatant

Moisture

/

99.75

90.00

99.95

TS

/ w.b.

0.25

10.00

0.05

VS

lb/1000 gal

9.16

383.18

1.67

FS

h

11.66

449.82

2.50

COD

h

12.50

433.16

1.25

BOD5

h

2.92*

0.29

N

h

1.67

20.83

0.17

NH4-N

h

1.00

4.17

0.10

p4

h

0.48

9.16

0.08

K

h

4.17

12.50

C:N ratio

3

10

* Milk house and milking parlor wastes only.

* Milk house and milking parlor wastes only.

Figure 4-1 Dairy manure solids production

"o

9,000 10,000

"o

-

-

A

- a 1400 lb cow

A

10

00

l

b

co

w

1

Note: FS = TS- VS

T

I

1

1

I

1

1

1

9,000 10,000

12,000 14,000 16,000 Milk production, lb/yr

18,000 20,000

12,000 14,000 16,000 Milk production, lb/yr

18,000 20,000

Table 4-8 lists characteristics of "as excreted" beef manure. Beef waste of primary concern are those from the feedlots (table 4-9). The characteristics of these solid wastes vary widely because of such factors as climate, diet, feedlot surface, animal density, and cleaning frequency. The soil in unsurfaced beef feed-lots is readily incorporated with the manure because of the animal movement and cleaning operations. Wasted feed is an important factor in the characterization of beef wastes.

Beef feedlot runoff water also exhibits wide variations in character (tables 4-10 & 4-10a). The influencing factors that are responsible for feedlot waste variations are similar to those listed for solid wastes. Surfaced feedlots produce more runoff than unsurfaced lots.

Table 4-8

Beef waste characterization — as excreted*

Component

Units

Feeder, yearling - 750 to 1,100 lb -High High forage energy diet diet

450 to 750 lb

Feeder, yearling - 750 to 1,100 lb -High High forage energy diet diet

Weight

lb/d/1000#

59.10

51.20

58.20

63.00

Volume

ft3/d/1000#

0.95

0.82

0.93

1.00

Moisture

%

88.40

88.40

87.00

88.40

TS

% w.b.

11.60

11.60

13.00

11.60

lb/d/1000#

6.78

5.91

7.54

7.30

VS

it

6.04

5.44

6.41

6.20

FS

h

0.74

0.47

1.13

1.10

COD

h

6.11

5.61

6.00

6.00

BOD5

h

1.36

1.36

1.30

1.20

N

h

0.31

0.30

0.30

0.33

P

h

0.11

0.094

0.10

0.12

K

h

0.24

0.21

0.20

0.26

C:N ratio

h

11

10

12

10

Average daily production for weight range noted. Increase solids and nutrients by 4% for each 1% feed waste more than 5%.

Average daily production for weight range noted. Increase solids and nutrients by 4% for each 1% feed waste more than 5%.

Chapter 4

Agricultural Waste Characteristics

Table 4-9 Beef waste characterization — feedlot manure

Table 4-10 Beef waste characterization — feedlot runoff pond

Component Units

Unsurfaced lot*

- - Surfaced lot** - -High High forage energy diet diet

Component

Units

Weight

Moisture

C:N ratio lb/d/1000#

* Dry climate (annual rainfall less than 15 inches); annual manure removal.

** Dry climate; semiannual manure removal.

Moisture

NH4-N

99.70

82.80

0.30

17.20

7.50

644.83

17.50

788.12

11.67

644.83

1.67

51.66

1.50

17.50

7.50

14.17

Table 4-10a Nitrogen content of cattle feedlot runoff (Alexander and Margheim 1974)1

Annual rainfall Below-average conditions2 Average conditions3 Above-average conditions4

<25 inches 360

25 to 35 inches 60

>35 inches 15

110 60 30 15

10 5

1 Applies to waste storage ponds that trap rainfall runoff from uncovered, unpaved feedlots. Cattle feeding areas make up 90 percent or more of the drainage area. Similar estimates were not made for phosphorus and potassium. Phosphorus content of the runoff will vary inversely with the amount of solids retained on the lot or in settling facilities.

2 No settling facilities are between the feedlot and pond, or the facilities are ineffective. Feedlot topography and other characteristics are conducive to high solids transport or cause a long contact time between runoff and feedlot surface. High cattle density—more than 250 head per acre.

3 Sediment traps, low gradient channels, or natural conditions that remove appreciable amounts of solids from runoff. Average runoff and solids transport characteristics. Average cattle density—125 to 250 head per acre.

4 Highly effective solids removal measures, such as vegetated filter strips or settling basins that drain liquid waste through a pipe to storage pond. Low cattle density—less than 120 head per acre.

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