Management of Organic Waste

52

Picture 1. Polyurethane carrier with adhered A. suum eggs

Picture 2. Perforated plastic nets with the carriers
The samples were examined for the pH (1:10 water extract) using a pH electrode (HACH
Company, Loveland, Colorado, USA). Dry matter (drying at 105°C to a constant weight),
residum-on-ignition (550°C for 4 h), and water soluble ammonium nitrogen (NH
4
+
) by
titration (Mulvaney, 1996). Soluble and insoluble substances were determined by
evaporation of the known amount of homogeneous sample filtrate on a water bath after

The Sanitation of Animal Waste Using Anaerobic Stabilization

53
absorption of insoluble substances on a filter, drying the evaporation residue at 105°C and
determining its weight. COD was determined on the basis of organic substances oxidation
in sample by potassium dichromate in sulfuric acid medium during 2-hour boiling in a COD
reactor (HACH Company, Loveland, Colorado, USA). Portion of samples for N
t

determinations were digested using a HACH-Digesdahl apparatus (HACH Company,
Loveland, Colorado, USA). N
t
was distilled with NaOH (40 %) (Bremner, 1996). The C

(Picture 5) and that of
smaller lagoon is 5 000 m
3
. Both lagoons serve as reservoirs of digested slurry. Liquid
fraction from the smaller lagoon was carried away and spread on fields. The presence and
survival of parasite eggs were studied in the larger lagoon. Samples were taken from raw
slurry collecting basin before the inlet in to bioreactor (input samples), from outlet of
digested slurry after methanogenesis in bioreactor (output samples), from supernatant
(liquid fraction) and from lagoon sludge (solid fraction - sediment). The slurry samples for
parasitological and physical and chemical examination were collected monthly during 29
month.
Slurry from the pig farm stored in the collecting basin showed a considerable variability
during the period of study (Table 1). Compared with mean pH value of 7.12 ± 0.26, pH raw
slurry in the month 11, 17 and 21 was lower, ranging between 6.61 and 6.95. The most
conspicuous differences were recorded in DM content, which is most likely associated with
the amount of process water use. The DM content in raw slurry determined during the
period studied ranged from 0.81 % to 5.30 %. The amount of NH
4
+
in raw slurry was
between 821 mg.l
-1
and 1 774 mg.l
-1
. Chemical oxygen demand (COD) for that period varied
from 2 000 mg.l
-1
to 22 530 mg.l
-1
. The mean contents of N


56
This is caused by the projected input, reckoning on the 5 % of dry matter in raw pig slurry, but
the mean dry matter content in raw slurry supplied to bioreactor was 1.96 % and therefor
poultry excrements had to be regularly added (average DM content 22.27 %) to pig slurry
prior to its supply into bioreactor. Stabilized slurry outlet of bioreactor contained as much as
3.23 ± 2.54 % DM on the average. Anaerobic digestion increased slurry pH which was ranging
from 7.37 to 8.50. Compared with untreated slurry, anaerobic stabilization increased the
content NH
4
+
to 7.80 ± 0.29 mg.l
-1
on average. Concentration of N
t
was increased twice.

Storage
(month)
pH
COD
(mg.l
-1
)
DM

(%)
IM
(%)
OM

3
7.03 13 500 1.14 57.71 42.29 7 757 3 641 1 202 1 485
4
7.00 20 900 1.57 38.74 61.26 11 095 4 572 1 078 1 363
5
7.35 14 824 0.81 45.71 54.29 4 895 3 178 1 037 1 191
6
7.36 13 333 2.52 17.36 52.64 5 366 19 844 1 247 1 429
11
6.61 21 795 5.30 33.02 66.98 - - 1 695 1 089
17
6.95 12 750 0.95 30.53 69.47 1 000 8 500 1 478 1 010
21
6.95 22 530 2.80 19.97 80.03 5 870 22 130 1 358 1 872

Table 1. Physico-chemical properties of raw pig slurry (input sample of bioreactor) (COD –
chemical oxygen demand, DM - dry matter, IM - inorganic mater, OM - organic matter;
NH
4
+
- ammonium ions, N
t
- total nitrogen, - - not examined) Storage
(month)
pH
COD
(mg.l

-1
)
0
8.50 36 333 - - - - - 2 633 6 320
1
7.74 10 500 0.81 56.54 43.46 4 739 3 401 2 204 2 605
2
7.63 17 820 1.24 48.50 51.50 6 134 6 226 2 157 2 699
3
7.80 8 500 1.96 59.69 40.31 6 192 13 456 2 045 2 549
4
7.69 17 100 3.16 41.81 58.19 5 965 5 658 1 933 3 138
5
7.77 6 092 4.48 42.06 57.94 3 225 41 603 1 898 1 982
6
7.92 2 186 2.91 42.87 57.13 3 555 25 518 2 437 3 516
11
7.88 4 872 0.50 70.00 30.00 - - 2 171 1 530
17
7.37 7 750 6.45 39.84 60.16 1389 63 111 2 248 1 936
21
7.66 42 169 7.85 33.81 66.19 1 333 77 167 2 655 3 399

Table 2. Physico-chemical properties of digested pig slurry (output sample of bioreactor)
(COD – chemical oxygen demand, DM - dry matter, IM - inorganic mater, OM - organic
matter; NH
4
+
- ammonium ions, N
t

Sediment contained more DM and N
t
than supernatant (Tables 3, 4).

Storage
(month)
pH
COD
(mg.l
-1
)
DM

(%)
IM
(%)
OM
(%)
Soluble
substances
(mg.l
-1
)
Insoluble
substances
(mg.l
-1
)
NH
4

8.28 1 904 0.66 54.83 45.17 5 325 1 284 1 331 1 317
16
8.21 5 385 0.63 56.38 43.62 4 483 1 806 896 882
17
8.29 8 605 0.60 54.27 45.73 3 501 2 524 616 1 415
23
8.32 3 333 0.35 71.43 28.57 2 128 1 372 672 1 016
29
7.95 5 000 0.75 45.33 54.67 3 000 4 500 862 1 031
Table 3. Physico-chemical properties of supernatant from stabilized pig slurry stored in lagoon
(COD – chemical oxygen demand, DM - dry matter, IM - inorganic mater, OM - organic
matter; NH
4
+
- ammonium ions, N
t
- total nitrogen, - - not examined)
A. sum eggs and Oesophagostomum sp. eggs were rarely detected in slurry on the input and
also on the output of bioreactor (Table 5). Similar results of helminths eggs occurrence in
anaerobic slurry treatment were also presented by Juriš et al. (1996), No helminth eggs were
found in the supernatant of digested slurry from the lagoon. A. suum eggs were found in
sediment (Table 5).
High percentage of devitalised unembryonated A. suum eggs (47.46 ± 0.78 %) stored 11
months (from May – month 13 to March - month 23) in a ground slurry lagoon points to the
impact of high concentration of NH
4
+
(max. 5 358 mg.l
-1
in sediment compared to 1 863 mg.l

(%)
Soluble
substances
(mg.l
-1
)
Insoluble
substances
(mg.l
-1
)
NH
4
+

(mg.l
-1
)
N
t

(mg.l
-1
)
0
8.37 9333 1.17 49.21 50.79 1 885 2 138 5 778 5 963
1
8.13 11000 1.17 48.26 51.74 1 681 1 830 5 635 6 041
2
8.07 6170 1,70 43.21 56.79 1 643 2 241 7 344 9 652
Table 5. Occurence of helminth eggs in slurry and in lagoon (A – A. suum eggs, Oe –
Oesophagostomum sp. eggs, ND – not detected, - - not examined)
Slurry
Storage (month) and occurence of eggs per litre sample
0 1 2 3 4 5 6 11 13 14 15 16 17 21 23 29
Input
(raw)
Oe-2 ND ND A-5 ND ND ND - - - - - - ND ND ND
Output
(digested)
A-2 ND ND ND ND ND ND - - - - - - ND A-1 ND
Supernatant
(lagoon)
ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND
Sediment
(lagoon)
ND ND A-6 ND ND ND ND ND ND ND ND ND ND A-2 ND ND

The Sanitation of Animal Waste Using Anaerobic Stabilization

59
Storage (month)
Damaged A. suum eggs (
x
%±SD)
Lagoon Control
May (13)
16.23 ± 3.22 14.80 ± 2.43

periodically stirred. The following variations were investigated in comparison to untreated
(control) manure (CM) and untreated dog droppings (CD):
a. manure mixed with quality dust lime in a concentration of 20 g.kg
-1
(ML20)
b. manure mixed with dust rejects in a concentration of 20 g.kg
-1
(M20)
c. dog droppings mixed with dust rejects in a concentration of 20 g.kg
-1
(D20),
d. dog droppings mixed with dust rejects in a concentration of 70 g.kg
-1
(D70).
Samples for parasitological and physical and chemical examinations were collected after 0,
1, 3, 8, 14, 36 (UM, ML20 and M20) and after 0, 1, 2, 3, 7, 8, 9, 10, 14, 73 (UD, D20, D70) days
of exposure. Three samples were taken and analysed at each of the given sampling intervals.
The physical and chemical properties of treated manure and dog excrements are given in
Tables 8 - 13. Comparison of the changes in The physical and chemical properties

of organic
material during anaerobic stabilisation with or withou dust rejects is given in Fig. 1 – 5.

Management of Organic Waste

60
Storage
(days)
pH
DM

8.27±0.06 14.36±0.12 9.48±0.13 90.52±0.13 48.75±2.80 32698.26±2378.98 14.13:1

Table 8. Physico-chemical properties of the pig manure during anaerobic stabilization (CM)
(DM - dry matter, IM - inorganic mater, OM - organic matter; NH
4
+
- ammonium ions, N
t
-
total nitrogen) Storage
(days)
pH
DM
(%)
IM
(%)
OM
(%)
NH
4
+

(mg.kg
-1
DM)
N
t

Storage
(days)

pH
DM
(%)
IM
(%)
OM
(%)
NH
4
+

(mg.kg
-1
DM)
N
t

(mg.kg
-1
DM)
C:N
0
8.47±0.58 33.22±6.88 8.09±2.57 91.91±2.57 120.89±7.05 13789.52±2356,62 34.27:1
1
12.86±0.03 30.33±3.87 48.90±15.23 51.10±15.23 126.24±9.84 37815.69±1860.53 6.97:1
3
12.96±0.01 37.31±3.89 57.40±5.92 42.60±5.92 130.15±9.01 35790.24±2332.63 6.08:1

(%)
NH
4
+

(mg.kg
-1
DM)
N
t

(mg.kg
-1
DM)
C:N
0
9.08±0.01 35.66±1.83 11.33±0.01 88.67±0.01 219.07±55,70 40758.43±1416.02 11.15:1
1
8.57±0.01 34.66±0.11 14.29±1.77 85.71±1.77 232.05±23,57 39116.17 ±207.87 11.24:1
2
9.61±0.01 35.20±4.23 19.21±4.89 80.79±4.89 395,72±2,48 41116.07±1205.26 10.12:1
3
9.78±0.01 37.56±1.93 22.33±1.06 77.67±1.06 309.78±95.04 44207.73±3222.05 9.05:1
7
9.01±0.01 37.17±0.29 20.58±0.48 79.42±0.48 370,89±8.22 23346.91±5147.86 18.06:1
8
9.39±0.02 33.21±0.18 22.46±1.97 77.54±1.97 82.25±2.55 12152.63±77.34 32.74:1
9
9.55±0.02 29.81±3.03 31.17±3.54 68.83±3.54 132.58±72.91 6556.92±818.39 54.92:1
10

t

(mg.kg
-1
DM)
C:N
0
8.41±0.05 37.21±0.01 16.04±4.81 83.96±4.81 400.57±47.84 45177.35±4724.10 9.64:1
1
11.21±0.02 44.47±0.91 39.37±0.10 60.63±0.10 12.51±8.65 32262.40±4212.96 9.66:1
2
9.34±0.03 56.45±15.15 62.63±19.97 37.37±19.97 36.17±7.84 16218.95±2664.67 12.44:1
3
8.58±0.01 57.28±33.23 60.29±28.06 39.71±28.06 645.10±362.56 45266.01±19058.77 4.23:1
7
9.08±0.01 45.11±6.79 43.58±0.64 56.42±0.64 225.45±91.01 22104.48±11603.90 15.37:1
8
9.13±0.01 43.90±2.84 41.87±0.96 58.13±0.96 439.78±141.28 18254.61±1760.78 16.74:1
9
9.27±0.05 68.66±1.32 27.61±0.60 72.39±0.60 398.59±2.51 18083.74±303.53 20.86:1
10
9.12±0.04 64.15±0.16 42.28±0.71 57.64±0.71 349.02±10.08 16966.79±191.73 17.70:1
14
8.91±0.03 60.02±0.98 49.20±4.49 50.80±4.49 338.50±24,95 17963.19±457.92 14.71:1
73
8.69±0.01 89.06±0.01 38.85±3.90 61.15±3.90 74.54±26.60 13972.75±1214.80 22.56:1
Table 12. Physico-chemical properties of the dog excrements mixed with dust rejects in a
concentration of 20 g.kg
-1
during anaerobic stabilization (D20) (DM - dry matter, IM - inorganic

9.08±0.01 35.66±1.83 11.33±0.01 88.67±0,01 219.07±55.70 40758.43±1416.02 11.15:1
1
12.58±0.04 43.11±1.51 58.48±9.02 41.52±9,02 41.04±42.79 13041.67±2498.12 16.22:1
2
12.68±0.01 46.81±0.17 62.89±2.38 37.11±2,38 10.19 4555.21±936.46 42.69:1
3
12.64±0.01 44.10±1.95 57.53±1.39 42.47±1,39 20.65±14.40 6868.28±1649.01 32.67:1
7
12.36±0.01 45.50±0.21 60.84±0.47 39.16±0,47 140.34±9.77 26830.72±6801.00 7.73:1
8
10.63±0.01 45.22±0.48 62.63±2.26 37.37±2,26 131.32±2.98 14216.80±5981.61 15.04:1
9
10.12±0.01 45.60±1.23 60.40±4.67 39.60±4.67 82.59 16161.23±10202.44 16.18:1
10
10.06±0.02 46.75±1.09 63.09±0.21 36.91±0.21 85.65±10.62 13399.86±759.04 14.14:1
14
9.82±0.01 52.21±1.08 65.03±0.80 34.97±0.80 14.28 19371.98±1147.30 9.21:1
73
8.97±0.02 87.17±0.47 40.50±1.92 59.50±1.92 2.20±0.08 12440.27±566.93 24.43:1
Table 13. Physico-chemical properties of the dog excrements mixed with dust rejects in a
concentration of 20 g.kg
-1
during anaerobic stabilization (D70) (DM - dry matter, IM - inorganic
mater, OM - organic matter; NH
4
+
- ammonium ions, N
t
- total nitrogen, - - not examined)


with or without dust rejects
Fig. 4. Comparison of the changes in N
t
of organic material during anaerobic stabilisation
with or without dust rejects

Management of Organic Waste

64

Fig. 5. Comparison of the changes in C:N ratio of organic material during anaerobic
stabilisation with or without dust rejects
The Table 14 indicates that a 24 hour after application of both types of lime at concentration
20 g.kg
-1
manure more than 80 % of model unembryonated A. suum eggs were devitalised.
A. suum eggs were totally devitalised as early as till 36 days after application of lime in
manure. 58.13±6.89 % of eggs were devitalised in the control without dust reject in the end
of experiment.
Storage
(days))
Demaged A. suum eggs (x%±SD)
CM ML20 M20
0

and within 21 days after application of dust rejects at a
concentration of 20 g.kg
-1
due to the changes in physical and chemical properties of the
stabilised materials (Tables 12, 13). 57.23±3.21 % of eggs were devitalised in the control
without dust reject in the end of experiment (Table 15).

Storage (days)
Demaged A. suum eggs (x%±SD)
CD P20 P70
0
12.62±1.14 12.62±1,14 12.62±1.14
1
35.70±2.46 65.65±2.84** 77.05±2.36***
2
54.43±10.66* 68.65±3.89** 82.30±4.81***
3
67.00±2.55** 75.15±1.21** 87.60±3.98***
7
62.65±4.03** 76.25±5.41** 97.13±3.97***
8
59.80±2.71* 76.93±2.69*** 100***
9
61.87±2.90* 82.30±4.81*** 100***
10
62.85±4.03* 85.69±1.45*** 100***
14
61.96±3.26* 95.69±6.35*** 100***
21
55.65±2.36* 100*** 100***