Design of anaerobic plants
concentration does not yield any special effect, whereas a constant exposure at
lower concentrations will cause inhibition in the long run. For almost all toxic
substances in moderate doses it applies, however, that in the event of a long-term
exposure of the sludge, a sludge will be developed (selected) which can better
withstand the toxic substance.
Influence
Primary influence of control parameters, change/velocity
(so strong that the pro- Biological effect
cess is influenced)
Volatile fatty acids Gas production
pH
Increased load with
3-stage-process is is increased I
is increased I
is reduced/
dissolved organic
disturbed
quickly
quickly
moderately
matter
Increased load with
3-stage-process
is increased/
is increased I
suspended organic
is disturbed/
moderately
moderately
matter
washout
Increased input of in- washout
is increased/slowly is reduced/slowly
organic suspended solids
Increased amount of
washout
is increased/slowly is reduced/slowly
suspended solids in
effluent
Temperature variation 3-stage-process is is increased/ quickly is reduced/ quickly is reduced/
disturbed
moderately
pH increase in influ(inhibition)
(is increased/
(is reduced/
is increased/
ent (and reactor)
quickly)
quickly)
quickly
pH decrease in influinhibition
is increased/
is reduced/ quickly is reduced/ quickly
ent (and reactor)
quickly
Sulphate in influent
inhibition
is increased I
is reduced/ quickly is reduced/
quickly
moderately
Ammonium in influinhibition
is increased/
is reduced/ quickly is reduced/
ent
quickly
moderately
Organic nitrogen in
inhibition
is increased/
is reduced/
is reduced/slowly
influent
moderately
moderately
Toxic substances in
inhibition
is increased I
is reduced/ quickly is reduced/
influent
quickly
moderately
Table 9.11
Disturbances in anaerobic processes.
Parameter
Inhibition by single dose
Inhibition by continual supply
pH
<6
<5
>8
>8.5
Ammonia, free, Nfu
> 100gN/m 3
>200gN/m 3
Hydrogen sulphide, HzS
>250g/m 3
> 1000 g/m 3
Cyanide, CN>5g/m 3
> 100 g/m 3
Trichloromethane
> 1 g/m 3
>50g/m 3
Formaldehyde
> 100g/m 3
> 400g/m 3
Nickel,Ni
> 200 g/m 3
>50 g/m 3
Table 9.12
Anaerobic wastewater treatment. Inhibition /7/./8/,/9/.
308
concentration does not yield any special effect, whereas a constant exposure at
lower concentrations will cause inhibition in the long run. For almost all toxic
substances in moderate doses it applies, however, that in the event of a long-term
exposure of the sludge, a sludge will be developed (selected) which can better
withstand the toxic substance.
Influence
Primary influence of control parameters, change/velocity
(so strong that the pro- Biological effect
cess is influenced)
Volatile fatty acids Gas production
pH
Increased load with
3-stage-process is is increased I
is increased I
is reduced/
dissolved organic
disturbed
quickly
quickly
moderately
matter
Increased load with
3-stage-process
is increased/
is increased I
suspended organic
is disturbed/
moderately
moderately
matter
washout
Increased input of in- washout
is increased/slowly is reduced/slowly
organic suspended solids
Increased amount of
washout
is increased/slowly is reduced/slowly
suspended solids in
effluent
Temperature variation 3-stage-process is is increased/ quickly is reduced/ quickly is reduced/
disturbed
moderately
pH increase in influ(inhibition)
(is increased/
(is reduced/
is increased/
ent (and reactor)
quickly)
quickly)
quickly
pH decrease in influinhibition
is increased/
is reduced/ quickly is reduced/ quickly
ent (and reactor)
quickly
Sulphate in influent
inhibition
is increased I
is reduced/ quickly is reduced/
quickly
moderately
Ammonium in influinhibition
is increased/
is reduced/ quickly is reduced/
ent
quickly
moderately
Organic nitrogen in
inhibition
is increased/
is reduced/
is reduced/slowly
influent
moderately
moderately
Toxic substances in
inhibition
is increased I
is reduced/ quickly is reduced/
influent
quickly
moderately
Table 9.11
Disturbances in anaerobic processes.
Parameter
Inhibition by single dose
Inhibition by continual supply
pH
<6
<5
>8
>8.5
Ammonia, free, Nfu
> 100gN/m 3
>200gN/m 3
Hydrogen sulphide, HzS
>250g/m 3
> 1000 g/m 3
Cyanide, CN>5g/m 3
> 100 g/m 3
Trichloromethane
> 1 g/m 3
>50g/m 3
Formaldehyde
> 100g/m 3
> 400g/m 3
Nickel,Ni
> 200 g/m 3
>50 g/m 3
Table 9.12
Anaerobic wastewater treatment. Inhibition /7/./8/,/9/.
308