Biogaspotential i skogsindustriellt slam

The impact of solids retention time in the aerated step of a pulp and paper mill effluent treatment on the bio methane potential of

waste activated sludge (Master Thesis )

Danish Mehmood [email protected]

0739458132 Chemical Engineering

Karlstad University

Introduction

•  Background •  Need of non-fossil fuel •  Bio Energy concept is growing worldwide •  Best alternate for fossil fuels •  Most economical way to save energy and power cost within industry

Wastewater treatment in pulp and paper industry

•  Primary treatment •  All settleable materials are removed from wastewater, this is called primary

sludge

•  Biological treatment •  Microorganisams convert organic matters into biomass, this called

biological sludge

Sequential  batch  reactor

Microorganisms in activated sludge

•  Two groups of microorganisms are present in activated sludge •  Protozoa (single cell) and metazoa multicell •  Four different types of protozoa present in activated sludge are amoeba,

ciliates ( free swiming and stalked) and flagellates •  Example of metazoa is rotifier

Microorganisams in activated sludge

Results and Discussion

Production of sludge

0

50

100

150

200

250

300

0 5 10 15 20 25 30 35 40

TSS  (mg/L)

Number  of  days

TSS  (Effluents)

SRT  2  

SRT  10  

SRT  20

Chemical oxygen demand (COD)

-­‐‑100

200

500

800

1100

1400

1700

2000

0 5 10 15 20 25 30 35 40

COD  (mg/l)

Number  of  Days

COD  (Effluent)

SRT  2

SRT  10

SRT  20

Production of sludge

0

1000

2000

3000

0 10 20 30 40

TSS  of  sludge

[mg/l]

days  of  operation

SRT  2  days

SRT  10  days

SRT  20  days

0 500 1000 1500 2000 2500

0 10 20 30

VSS  of  sludge

[mg/l]

days  of  operation

SRT  2  days

SRT  10  days

SRT  20  days

Sludge volume index (SVI)

1077

730

434

103

82

42

0

20

40

60

80

100

120

140

160

180

200

0

200

400

600

800

1000

1200

SRT  2  days SRT  10  days SRT  20  days

Sludge  volume  index

[ml/g]

Daily  sludge  production

[mg/day]

Methane yield from lab produced sludges

0

20

40

60

80

100

120

0 5 10 15 20 25

Methane  yield

[Nml]

Days  of  operation

Specific  production  SRT  2  days

Specific  production  SRT  10  days

Specific  production  SRT  20  days

Total  production  SRT  2  days

Total  production  SRT  10  days

Total  production  SRT  20  days

Methane % from lab produced sludges

0 10 20 30 40 50 60 70

0 5 10 15 20 25

Methane  %

Days  of  operation

SRT  20

0 10 20 30 40 50 60 70

0 5 10 15 20 25

Methane  %

Days  of  operation

SRT  10

0 10 20 30 40 50 60 70

0 5 10 15 20 25

Methane  %

Days  of  operation

SRT  2

Methane yeild from mill Substrate with different SRT:

0

50

100

0 5 10 15 20 25

Methane  Yield  (ml)

Days  of  operation

B  3

0 20 40 60 80 100 120 140

0 5 10 15 20 25

Methane  Yield  (ml)

Days  of  operation

R  S

0

5

10

15

20

0 5 10 15 20 25

Methane  Yield  (ml)

Days  of  operation

B  2

Conclusion

Conclusion Lab produced sludge: •  Activated sludge produced through SBR has great potential of methane

gas •  Sludges of all three SRT gave high yeild of methane gas •  SRT 2 showed a higher amount of methane yeild than other two sludges, •  Maximum methane production was obtained in first week of operation, this

trend decreased with time

Conclusion Mill sludge: •  Sludge from mill showed totally different behaviour than lab produced

sludge •  B2 which is most thin sludge gave minimum or almost no methane •  B3 gave maximum methane yeild •  Methane production (%) increased gradually with time, in first week it was

minimum but increased afterward