Environmental Engineering Reference
In-Depth Information
taBle 32.6
Inhibitory and toxic concentrations of heavy metals
toxicity to adopted
microorganisms
a
[mg/l]
metal Ion
Inhibition start
a
[mg/l]
Cr
3 +
130
260
Cr
6 +
110
420
Cu
40
170
Ni
10
30
Cd
70
600
Pb
340
340
Zn
400
600
a
As inhibitory concentration, it is considered the first value that shows
diminished biogas production and as toxic concentration it is considered
the concentration at which biogas production is diminished by 70%.
Substrates for
biogas production
Additives
(alkaline solutions,
nutrients, ...)
Dilution
water
Pretreatment
(mechanical, thermal,chemical,
biological, enzymatic,...)
Water recirculation
Anaerobic
digestion
Parasitic energy
Digested material
collection
Biogas capture
Biomass recirculation
Biogas treatment
purification
Digested material
treatment
(dewatering)
Biogas use:
-Heat & power
-Fuel
-Gas network
-Raw material
...
Digested material
use:
-Fertilizer (solid &
liquid)
-Further treatment
(aerobic, compositing)
-Disposal
...
FIGure 32.3
Block scheme of anaerobic digestion, biogas use, and digested material use.
