Anaerobic processes
bacteria, inhibition will normally be observed for these bacteria at first. Table 3.16
gives some examples of concentrations of toxic substances which influence the
processes. Just like other biological processes, the anaerobic processes can develop
resistance to toxic substances which can also be seen in the table.
Parameter
Inhibition by single dose
Inhibition by continued supply
pH
<6
pH
>8
Ammonium, NHt
> 100 g/m 3
Hydrogen sulphide, H2S
>250 g/m 3
Cyanide, CN> 5g/m 3
Trichloromethane
> 1 g/m 3
Formaldehyde
> 100 g/m 3
Nickel
> 200 g/m 3
Table3.16
Toxic substances, anaerobic processes.
Reaction rate constants, anaerobic processes
Table 3.17 gives examples of reaction rate constants.
Symbol
Unit
Maximum specific growth rate,
J..lmax,S
d-1
acid-forming bacteria
Maximum specific growth rate,
J..lmax,M
d-1
methane-forming bacteria
Maximum yield constant,
Ymax,S
kgCOD(B)
acid-forming bacteria
kgCOD(S)
kgVSS
kgCOD(S)
Maximum yield constant,
Ymax,M
kgCOD(B)
methane-forming bacteria
kgCOD(S)
kgVSS
kgCOD(S)
Hydrolysis constant, suspended solids
kh
d-1
Hydrolysis constant, dissolved solids
kh
d-1
khX
kgCOD(X) . d-1
kgCOD(B)
Hydrolysis saturation constant
Kx
kgCOD(X)
kgCOD(B)
Saturation constant, acid step
Ks,s
kg COD(S)/rn 3
Saturation constant, methane step
Ks,M
kg COD(S)/rn 3
Inhibition constant, acetic acid,
K1
kg COD(S)/rn 3
methane step
Table3.17
Reaction rate constants, anaerobic processes, 35°C.
108
<5
>8,5
> 200 g/m 3
> 1000g/m 3
> 100g/~ 3
> 50 g/m 3
> 400g/m 3
> 50 g/m 3
Quantity
1-3
0.3-0.5
0.2-0.3
0.15-0.20
0.04-0.05
0.03-0.04
0.3-0.7
2-20
0.3-0.7
0.02-0.05
0.03-0.15
0.03-0.10
0.2-0.8