1. Aare Kuusik, E. Loigu, O. Sokk, Argo Kuusik Estonia
Enhancement of Methane Productivity of Anaerobic Reactors of Wasterwater Treatment Plants
Aare Kuusik, E. Loigu, O. Sokk, Argo Kuusik Estonia

2. Objectives of Experiments:
Enhancement of methane productivity of existing anaerobic reactors
To get rid of inconvenient waste solids: waste glycerol and fishery residues
To resolve above problems in one process

3. Self-made Reactor

4. Self-made Reactors

5. Manufactored Reactors Armfield W8

6. Technological Scheme of Self-made Reactor

7. Technological Scheme of Manufactured Reactor

8. Maintenance of Reactors
Mesophilic temperature oC, mainly oC
Batch type or fill and draw input-output of sludge every morning
Before and after the input-output process the contents of the reactors were mixed
Produced biogas was evaluated

9. Concentrations were measured
Every morning: pH, H2S, NH3, CO2, O2
Once a week: TS and VS, VFA and alkalinity
of input and output sludge

10. The data of the single sludge digestion was summarised
Days consi-dered
Reten-tion ti-me, days
Volume load TS kg/m3
Input,
g/L
Output,
Organic removal input-output, g/L TS VS
∆TS
∆VS
9 -21 40
0.885
35.4
26.625
22.375
14.05
13.025
12.625 35
1.011
35.394
26.62
22.159
13.234
1338.8
31 – 41 30
1.088
32.644
24.169
22.331
13.819
10.313
10.35
42 – 55 25
1.048
26.203
16.25 20
1.601
32.025
21.863
13.713
10.163
8.663
Average
1.227
31.972
22.693
22.1
13.728
11.242
10.504

11. Continuation of previous table (single sludge)
Retention time, days
Tempe-ratureoC
Methane yield
Methane contents in biogas %
Solid removal %
Per volume L/m3
TS removed L/∆kg
∆TS
∆VS 40
36,5
109.7
339.6
50.98
36.51
47.23 35
37,4
82.1
217.1
51.84
37.40
50.25 30
36,4
92.9
270.3
52.16
31.59
42.81 25
38,5
117.9
54.51 20
37,9
171.5
337.24
57.59
31.75
38.68
Average
37.2
128
310.9
54.39
33.55
42.95

12. Admixed sludge (sludge 98% + 2% waste glycerol) digestion
Days consi- dered
Reten- tion time, days
Volum load, TS kg/m3/d
Input, g/L
Output, g/L
Difference between input- output, g/L TS VS
∆TS
∆VS
12 – 19 40
1.315
52.575
42.375
23.0
14.525
29.575
27.85
20 – 39 35
1.458
51.034
40.994
23.166
14.328
27.869
26.666
40 – 63 30
2.567
44.925
34.613
23.269
10.448
21.656
24.169
64 – 75 25
2.110
52.75
41.125
30.672
17.891
22.078
23.234
76 – 80 20
2.497
49.938
38.213
24.543
9.536
25.4
16.175
Average
2.016
49.307
38.756
24.588
13.274
24.720
24.578

13. Continuation previous table (sludge 98% + glycerol 2%)
Reten- tion time, days
Tempe- rature oC
Methane yield
Methane contents in biogas, %
Solid removal %
Per reac- tor volu- me, L/m3
Per TS removed, L/∆kg
∆TS
∆VS 40 37
336.7
483.5
62.71
56.3
65,72 35
268.8
352.8
61.17
54.62
65,06 30
39.3
287.3
356.6
61.81
48.19
69,82 25
36.5
386.8
416.3
60.05
41.85
56,49 20
37.9
536.7
374.2
61.75
50.85
75,06
Average
37.8
323
381.9
61.42
50.1 66

14. The weighted means of experiments
Subs-trate
Days consi-dered
Retention time,
days
TS input,
g/L
VS input,
TS output,
VS output,
∆TS,
∆VS,
Sludge 100% 73
27.6
32.0 ( )
22.7 ( )
22.1 ( )
13.7 ( )
11.2 ( )
10.5 ( )
Sludge 98% + glycerol 2% 69
31.0
49.3 ( )
38.8 ( )
24.6 ( )
13.3 ( )
24.7 ( )
24.6 ( )
Sludge 95% + glycerol 5% 70 35
64.0 ( )
58.6 ( )
27.0 ( )
15.1 ( )
44.5 ( )
43.7 ( )
Sludge 98% + fish 2% 29
35.7
43.0 ( )
32.4 ( )
23.8 ( )
14.0 ( )
20.8 ( )
18.4 ( )

15. Continuation of weighted means table
Substrate
Methane yield
Methane contents in biogas %
Solid removal %
Per volume ,L/m3
Per remo-ved TS, L/∆kg
∆TS
∆VS
Sludge 100%
128 (82-172)
310.9 ( )
54. ( )
33.6( )
43( )
Sludge 98% +2% glyc.
323( )
381.9( )
61.4( )
50.1( )
66( )
Sludge 95% + 5% glyc.
488.6( )
386.1( )
59.3( )
62( )
74.3( )
Sludge 98% +2% fish
369.4( )
627.7( )
63.5( )
48.5( )
56.8( )

16. Percentage comparison of essential weighted means (in brackets)
Substrate
Retention time in days
Percentage relations
TS load per reactor volume
(kg/m3)
Solids residue after treatment
(g/L)
CH4 produc. per reactor volume, (L/m3)
Raw sludge 100%
100 (1,227)
100 (22.1)
100 (128)
Sludge 98%+ glycerol 2%
164 (2.016)
111.3(24.588)
252 (323)
Sludge 95% + 5% glycerol
40 – 20
173.1(2.124)
122.1(26.994)
382 (488.6)
Sludge 98% + fish resid. 2%
99 (1.215)
107.9(23.836)
288.6(369.4)

17. THANK YOU FOR YOUR ATTENTION