J. agric. Engng Res. (1980) 25, 375-380

A Pilot Scale Treatment Process for Laying Hen Manure

A. T. SOBEL*

The use of carbonaceous additives to increase handling ease, alter the physical appearance and reduce the pollution potential of animal manures presents itself as an approach to solving many waste management problems. The results of pilot scale studies concerned with the addition of wood shavings to laying hen manure indicate that the resulting product is storable and has an altered appearance.

Introduction

A horizontal batch mixer was adapted to process laying hen manure by the addition of wood sawdust. This mixer had a capacity of 0.5 m3 and was powered by a 2 hp, 3-phase electric motor. The motor was controlled by a time clock to run a preset time each hour. The mixer was insulated with 5 cm of polyurethane.

The mixer was initially filled with approximately 9 1 kg of previously hand-processed material. At 3-4 day intervals approximately 22.7 kg of material was removed and 22.7 kg of manure and sawdust was added. The theoretical retention time was 14 days. The sawdust was a coarse material of mixed woods and had a moisture content between 20 and 40% on a wet basis (wb). The manure was from caged White Leghorn laying hens housed at the Agricultural Waste Manage- ment Laboratory, New York State College of Agriculture and Life Sciences, Cornell University. The manure had been partially dried using the slot-outlet system of undercage drying. The manure produced from this system had a moisture content of 30-50 % (wb).

The oxygen content of the air within the manure-sawdust mixture was measured using an oxygen probe. The probe was placed within the material just after the material had been mixed and periodic measurements were taken. While this was a unique use of equipment designed for measuring the dissolved oxygen of a liquid, the information obtained indicated the uptake of oxygen by the microorganisms within the system. Fig. 2 shows such an oxygen uptake study and indicates that in 30 min the oxygen within the mixture had been reduced to 25 7: of that in the surrounding air. The mixing sequence was therefore set for the mixer to be on 10 s every 30 min.

Temperatures were taken inside the mixer during operation. Fig. 2 shows this temperature for several cycles of feeding and weighing plus a time when the mixer was accidentally left switched on. The temperature reached an average maximum of 125F.

Mass balance After the mixer had been in operation for 20 days and after conditions had been established

within the mixer, a detailed record was kept of the parameters of the process for a 35-day period. The operating procedure was similar for that followed in the initial period. The amount of saw- dust added was calculated to produce an approximate 20% sawdust : 80% manure ratio by weight for 30% moisture manure. This is equivalent to 0.36 kg sawdust per kg of total solids. Adjustment was made for changes in moisture content of the manure added but not for changes in sawdust as this all came from a common supply. Water was added to the mixture in the mixer to replace evaporation. To keep an approximate equal amount in the mixer, during each feeding the entire contents of the mixer were removed, weighed, and a constant weight (68 kg) was placed back into the mixer. Tables I and II present the various parameters for this study including a

*Department of Agricultural Engineering, New York State College of Agriculture and Life Sciences, Cornell University, Ithaca, New York

Received 19 December 1978; accepted in revised form 10 May 1980

315

OW-8634/80/040375 t-06 SOZ.OO/O fi? 1980 The British Society for Research in Agricultural Engineering

376 TREATMENT OF HEN MANURE

Fig. 1. Oxygen uptake within mixer

4Ol b I I I I I I, f:: I , , , , , , , , 0 20 40 60 00 100 120 I40 160 180

Tame (h)

Fig. 2. Temperature within mixer

Dat

e

30 N

ov.

197 1

3

Dec

. 19

71

7 D

ec.

1971

10

Dec

. 19

71

14D

ec.

1971

17

Dec

. 19

71

21 D

ec.

1971

24

Dec

. 19

71

28 D

ec.

1971

31

Dec

. 19

71

Ave

rage

92

.26

68.0

4 24

.14

68.5

9 30

.28

47.3

6

- I

TA

BLE

I

Mea

sure

d pa

ram

eter

s of

pilo

t m

anur

e tr

eatm

ent

proc

ess

Wet

wei

ghts

, kg

I- To

tal

in

Left

in

mix

er

mix

er

____

~ 72

.58

68.0

4 89

.36

68.0

4 68

.04

94.8

0 68

.04

99.3

4 68

.04

87.5

4 68

.04

100.

24

68.0

4 95

.26

68.0

4 94

.35

68.0

4 96

.16

68.0

4 92

.99

0

- I R

emov

ed

Tota

l A

sh,

from

mix

er

solid

s, %

%

4.54

21

.32

26.7

6 31

.30

19.5

0 32

.20

27.2

2 26

.31

28.1

2 (9

2.99

)

66.2

4 30

-45

39.5

6 68

.45

27.0

2 41

.34

65.6

9 30

.94

40.3

1 67

.87

30.0

7 45

.13

66.8

5 30

.07

49.1

5 72

.35

31.4

8 45

.31

70.6

8 30

.82

48.3

9 69

.7 1

30

.71

50.4

6 70

.06

29.9

9 62

.03

68.0

2 31

.28

51.9

7

Mix

ture

re

mov

edfr

om

mix

er

Nit

roge

n m

g/g

ts

Org

anic

-N

NH

,-N

15.2

0 14

.35

13.9

4 13

.88

15.3

2 13

.23

14.4

2 14

.74

16.2

7

16.0

9

14.7

4 67

.03

25.3

7 54

.41

9.20

Tota

l A

sh,

solid

s, %

%

63.2

7 69

.19

69.0

4 65

.95

66.4

4 67

.01

63.1

0 70

.53

68.7

3

-

Man

ure

adde

d to

mix

er

2544

21

.00

24.3

4 27

.71

27.1

6 24

.42

26.9

6 25

.78

25.5

3

NH

,-N

Nit

roge

n m

g/g

ts

Org

anic

-N

.___

57

.95

57.1

9 52

.25

63.4

1 54

.41

46.2

8 41

.40

49.0

0 67

.80

9.92

7.

79

8.38

12

.38

9.49

7.

80

8.99

7.

60

10.4

2

TABLEII

Mass

bala

nce

on p

ilot

man

ure

proc

ess

Ave

rage

to

tal

wet

wei

ght

in m

ixer

Ti

me

betw

een

feed

ings

Th

eore

tical

re

tent

ion

time

Tim

e of

tes

t pe

riod

Num

ber

of f

eedi

ngs

Tota

ls

duri

ng

test

pe

riod

W

et w

eigh

t of

man

ure

adde

d W

et w

eigh

t of

saw

dust

ad

ded

Wat

er

adde

d W

et w

eigh

t of

mix

ture

re

mov

ed

Evap

orat

ion

[153

,0+

10 (3

.74)

] W

ater

eva

pora

ted/

kg

vola

tile

solid

s lo

st

92.0

kg

3.5

days

13

.0 d

ays

35.0

day

s 10

294.

6 kg

40

.2 k

g 15

3.0

kg

241.

4 kg

19

0.4

kg

3.4

kg

Wet

0y

/lJ

S

olid

s,

Moi

stur

e /

, A

sh,

Vola

tile

TKN

w

eigh

t, so

lids

kg

kg

ash

kg

solid

s, ~~

kg

kg

m

glg

g

IN

Man

ure

29.4

6 67

.03

* 19

.75

9.71

25

.37*

5.

01

14.7

4 63

.61

1256

Sa

wdu

st:

4.02

60

,OO

t 2.

41

1.61

1.

00*

NEG

2.

41

NEG

N

EG

Tota

l 33

.48

66.1

9 22

.16

11.3

2 22

.61

5.01

__

\-___

. 17

.15

56.6

8 12

56

OU

T M

ixtu

re

24.1

4*

68.5

9*

16.5

6 7.

58

30.2

8*

5.01

11

.55

62.1

0 10

28

Cha

nge

- 9.

34

- 5.

60

- 3.

74

0 -5

.60

- 22

8

A C

hang

e -

27.9

-

25.3

0

- 32

.6

-18.

1 I

Org

anic

-N

mgl

g g

54,4

1*

1074

N

EG

NEG

48.4

6 10

74

47.3

6*

78

4 -

290

- 27

.0

I N

H,-N

mgl

g g

9.20

* 18

2 N

EG

NEG

8.21

18

2

14.7

4*

244

+62

+ 34

.1

* M

easu

red

valu

es--

all

othe

r va

lues

ar

e ca

lcul

ated

:

~;pl

atio

ns

assu

me

ash

rem

ains

co

nsta

nt

and

ash

in

equa

ls as

h ou

t 0

by

wei

ght

TKN

-Tot

al

Kje

ldah

l N

itrog

en;

NEG

-Neg

ligib

le

A. T. SOBEL 379

mass balance on the solids and forms of nitrogen. The comparison was made based on the assumption that the fixed solids (ash or inorganic matter) remained constant and did not accumu- late within the mixer, i.e. equal amounts of fixed solids were added and removed during each feeding.2

The mass balance indicates that there was a loss of nitrogen and a substantial conversion of organic nitrogen to ammonia. This was apparent during the operation of the unit by a strong ammonia odour. Considerable evaporation occurred with 3.4 kg of water evaporated per kg of volatile solids lost. Assuming all the heat for evaporation to come from the decomposition of manure solids, the energy used for the evaporation of water was approximately 2000 kcal/kg organic matter destroyed. The energy potential of laying hen manure is 4000 kcal/kg of volatile solids3 The portion of the released energy used for evaporation was therefore 50;.

Storage of processed material-uncovered

The processed manure from the mass balance study was placed as removed from the mixer into an outside storage. This storage was a simple 2.5 x 2.5 m plywood frame 0.6 m high. No cover was provided and the manure was exposed to the rain, snow and sun. The mixture remained in the storage for 5 months after the last material was added. At this time samples were taken from various areas of the pile and the material was utilized for a home vegetable garden. Table III presents the analysis of the manure at the end of the storage period. A fertilizer analysis on the material from the storage indicated 2.9 % P and 2.14 y/, K. With an average nitrogen content of 4f,; and expressing the P and K as P,O, and KzO. the fertilizer value was therefore 4.0-6.6-2.6.

The material was of granular nature and easy to handle. The material did not resemble man- ure, but was similar in appearance to high organic soil or leafmould.

TABLE III

Analysis of mixture stored outside uncovered

Moisture Location content,

% (wb) __~_

Centre of pile 34.48 Centre cross section, dry portion 31.06 10 cm from surface, high manure content 67.54 18 cm from surface, high sawdust content,

some fly larvae 66.94 Outside edge, very wet 70.77

______ Average 54.16

Total solids,

0, 0

Fixed solid.s,

I 0

65.52 21.30 68.94 28.88 32.46 42.35

33.06 35.27 29.23 41.28

45.84 33.82

Nitrogen, rng/x t.v

TKN ___~~

25.66 39.11 54.41

NH,-N

IO.81 15.48 34.60

47.92 31.68 34.38 13.37

39.90 21.19

Analysis of overall system

The overall system of treating laying hen manure would include predrying the manure under the caged birds, moving this to the mixer for combination with a carbonaceous additive such as sawdust, a period of time in the mixer for treatment, storage of the treated mixture, possible bagging of the stored material, and final use of the material as a soil conditioner. Based on analysis during the various components of such a system, the overall losses and concentrations are presented in Table IV. The composition of the As Produced manure was taken from References (4) and (5). The losses have been calculated based on the assumption that the fixed solids (ash) remain constant.

380 TREATMENT OF HEN MANURE

TABLE IV

Overall concentrations and losses for laying hen manure treatment system

Wet weight, W, units Moisture, m, % Total solids, S, %(100/A) Volatile solids, V, % of S (V/A) Fixed solids, A, % of S Nitrogen: TKN, % of S (N/A)

Organic N, % of S (ON/A) NH,-N, % of S (AN/A)

% loss (or gain) from As Producedt Wet weight Total solids Volatile solids Fixed solids Nitrogen: TKN

Organic-N NHS-N

As produced Predrying Treatment

100~00 35.28 75.004 32.97 25.004 (4.167) 67.03 (3.942) 76.00 (3.167) 74.63 (2.942) 24.004 25.37

7.5005 (0.3 125) 6.361 (0.2507) 6.97S (0.2906) 5.441 (0.2145) 0.5255 (0.0219) 0.920 (0.0368)

_ _

28.89 31.41 68.59 (3.302) 69.72 (2.302) 30.28

6,210 (0.2051) 4.736 (0.1564) 1.474 (0.0487)

Storage* ___._

38.70 54.16 45.84 (2.957) 66.18 (1.957) 33.82

3.990 (0.1180) 1,871 (0.0553) 2.119 (0.0627)

_--__-

0 - 64.72 71.11 -61.30 0 - 5.40 - 20.76 - 29.04 0 - 7.10 -27.31 - 38.21 0 0 0 0 0 - 19.78 - 34.37 - 62.24 0 -26.19 -46.18 - 80.97 0 + 65.75 + 122.37 + 186.30

-

- ?? Values presented are for the uncovered storage t Calculations based on assumption that fixed solids remain constant 4,s Data taken from References (4) or (5) as indicated

The major losses occurred during the storage portion of the system. There was a great increase in ammonia during the treatment and storage portions resulting in the ammonia being released.

Whilst these losses resulted in a stable material, the decrease in nitrogen (62 7:) represented a significant nutrient loss.

Conclusions

A manure treatment system was investigated that provided a storable product. This product had the advantages of granular nature making it easy to handle, low pollution potential, and altered appearance, making it more acceptable as a soil conditioner. The product had the dis- advantage of being low in nitrogen due to losses during treatment and storage.

REFERENCES

Sobel, A. T. Undercage drying of laying hen manure. Proc. Cornell Agricultural Waste Management Conf., Ithaca, New York, 1972 187-200

Sobel, A. T.; Ludingion, D. C. Management of laying hen manure by moisture removal-results of several research investigations. Proc. Cornell Agricultural Waste Management Conf., 1977 549-579

Sobel, A. T.; Ludington, D. C. Destruction of chicken manure by incineration. Management of farm animal wastes. ASAE Pub]. No. SP-0366. Proc. nat. Symp. Animal Waste Management, 1966 95-98

Sobel, A. T. Physicalproperties of animal manures associated with handling. ASAE Pub]. No. SP-0366. Proc. natn. Symp. Animal Waste Management, 1966 27-32

Hashimoto, A. G. Characterization of White Leghorn manures. Proc. Cornell University Agricultural Waste Management Conf., Ithaca, New York, 1974 141-152