Table 1 Physical and chemical process parameters of the pilot AD reactor prior to samplings for DNA extraction during the mesophilic and thermophilc test runs

Process parameters

OLR^*), kgVS m^-3d^-1

3

8

3

8-10

HRT ^**), days

22

10

23

9

Temperature, °C

36-37

36-37

54-55

54-55

pH

7.4-7.5

7.4-7.5

8.0-8.1

8.0-8.1

NH₄-N, g liter^-1

1.1-1.2

1.2-1.3

1.6-1.7

1.0-1.1

Alkalinity, mgCaCO₃ liter^-1

5400 - 6000

6300 - 6700

6200 - 6700

4900 - 5300

VFA^***), mg liter^-1

110 - 160

200 - 340

480 - 590

350 - 600

TS, %

3.1 – 3.2

4 – 4.5

3.2 – 3.3

3.7 – 4.2

VS, %

1.6 – 1.8

2.4 – 2.9

2.0 – 2.1

2.3 – 2.7

TS-reduction ^****), %

61 - 62

60 - 62

60 - 62

55 – 60

VS-reduction, %

72 - 74

66 - 69

70 - 71

64 - 70

Feed characteristics

TS, %

Biowaste (BW)

14.9 – 24.6

29 – 32.2

26.7

29.9 – 21.1

Sewage sludge (SS)

4.1 – 4.2

3.1 – 4.8

3.3 – 4.1

4.5 – 6.0

BW and SS mixture

8.6 – 10.3

11.8 – 13.0

10.7 – 10.9

9.5 – 10.6

VS, %

Biowaste (BW)

14.3 – 21.6

21.8 – 26.2

24.6

18 – 19.1

Sewage sludge (SS)

2.7 – 3.6

1.8 – 3.2

1.9 – 2.6

2.8 – 3.7

BW and SS mixture

6.2 – 8.4

7.9 – 8.8

8.7 – 9.2

7.4 – 8.0