enhancement of methane productivity of anaerobic reactors of wasterwater treatment plants aare...
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Enhancement of Methane Productivity of Anaerobic Reactors of Wasterwater
Treatment PlantsAare Kuusik, E. Loigu, O. Sokk, Argo Kuusik
Estonia
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
Self-made Reactor
Self-made Reactors
Manufactored ReactorsArmfield W8
Technological Scheme of Self-made Reactor
Technological Scheme of Manufactured Reactor
Maintenance of Reactors
• Mesophilic temperature 36-39 oC, mainly 37-38 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
Concentrations were measured
• Every morning: pH, H2S, NH3, CO2, O2
• Once a week: TS and VS, VFA and alkalinity
of input and output sludge
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, g/L
Organic removal input-output,
g/LTS VS TS VS ∆TS ∆VS
9 -21 40 0.885 35.4 26.625 22.375 14.05 13.025 12.62522 - 30 35 1.011 35.394 26.62 22.159 13.234 13.234 1338.831 – 41 30 1.088 32.644 24.169 22.331 13.819 10.313 10.3542 – 55 25 1.048 26.203 16.25 56 - 82 20 1.601 32.025 22.375 21.863 13.713 10.163 8.663
Average 1.227 31.972 22.693 22.1 13.728 11.242 10.504
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
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/LTS VS TS VS ∆TS ∆VS
12 – 19 40 1.315 52.575 42.375 23.0 14.525 29.575 27.8520 – 39 35 1.458 51.034 40.994 23.166 14.328 27.869 26.66640 – 63 30 2.567 44.925 34.613 23.269 10.448 21.656 24.16964 – 75 25 2.110 52.75 41.125 30.672 17.891 22.078 23.23476 – 80 20 2.497 49.938 38.213 24.543 9.536 25.4 16.175Averag
e 2.016 49.307 38.756 24.588 13.274 24.720 24.578
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 37 268.8 352.8 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
The weighted means of experimentsSubs-trate
Days consi-dered
Retention time,days
TS input,g/L
VS input,
g/L
TS output,
g/L
VS output,
g/L
∆TS,g/L
∆VS,g/L
Sludge 100%
73 27.6 32.0
(26.2-35.4)
22.7
(16.3-26.6)
22.1
(21.9-22.4)
13.7 (13.2-14.1)
11.2
(10.2-13.2)
10.5 (8.7-13.4)
Sludge 98% + glycerol
2%
69 31.0 49.3 (44.9-52.8)
38.8 (34.6-42.4)
24.6 (23.0-30.7)
13.3 (9.5-17.9)
24.7 (21.7-29.6)
24.6 (16.2-27.9)
Sludge 95% + glycerol
5%
70 35 64.0 (58.2-77.3)
58.6
(48.8-64.1)
27.0 (23.5-32.3)
15.1
(10.8-19.0)
44.5
(34.4-53.8)
43.7
(38.0-50.7)
Sludge 98% + fish 2%
29 35.7 43.0 (40.4-46.8)
32.4 (30.2-34.8)
23.8 (21.5-24.6)
14.0
(12.8-15.0)
20.8 (18.9-22.6)
18.4 (17.4-19.9)
Continuation of weighted means tableSubstrate 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 (217-340)
54. (51-57.6) 33.6(31.6-37.4)
43(38.7-50.3)
Sludge 98% +2% glyc.
323(269-537)
381.9(338-455)
61.4(60.1-62.7)
50.1(41.9-56.3)
66(65.1-75.1)
Sludge 95% + 5% glyc.
488.6(234.9-705.3)
386.1(273.1-530.4)
59.3(57-61.6)
62(54.7-69.6)
74.3(68.1-77.9)
Sludge 98% +2% fish
369.4(328.9-419.5)
627.7(582.6-686.2)
63.5(62.4-64.9)
48.5(46.7-50.7)
56.8(55.8-57.7)
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%
40 - 20 100 (1,227) 100 (22.1) 100 (128)
Sludge 98%+ glycerol 2%
40 - 20 164 (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%
40 - 30 99 (1.215) 107.9(23.836) 288.6(369.4)
THANK YOU FOR YOUR ATTENTION