Plant types, anaerobic processes
Fig 9.4
Anaerobic treatment plant with two separate anaerobic reactors. Suitable for wastewater with a high content of suspended solids.
can be removed in a traditional digester whereas the dissolved part of the organic
matter can be treated in one of the many plant types discussed in the next chapter.
Hyper-filtration can be used for concentration of dilute wastewater, for example
from ordinary households, or as an actual treatment process for the water phase in
highly concentrated wastewater types (industry, agriculture).
It applies for all plants with filters that a pretreatment is necessary to ensure against
clogging. The pretreatment can be anything from fine screening to hyper-filtration.
9 .2.2 Plants with suspended sludge
The plant type resembles activated sludge plants. The sludge is kept mechanically
stirred or in certain cases stirred through the gasification in the process and the
pumping in of wastewater.
The traditional plant is shown in Fig 9.5 and is called the contact process.
The biological process takes place in a tall tank, 5-10 m, whereas sludge separation
takes place by settling, lamella sedimentation, possibly with preceding degasification or refrigeration, see Fig 9.6.
Degasification or gas stripping prevents or delays the time for the production of
rising sludge as a certain gas production is going to take place after the degasification before the water is sufficiently super saturated for gas bubbles to be formed
Fig 9.5
Contact process, anaerobic wastewater treatment.
290
Fig 9.4
Anaerobic treatment plant with two separate anaerobic reactors. Suitable for wastewater with a high content of suspended solids.
can be removed in a traditional digester whereas the dissolved part of the organic
matter can be treated in one of the many plant types discussed in the next chapter.
Hyper-filtration can be used for concentration of dilute wastewater, for example
from ordinary households, or as an actual treatment process for the water phase in
highly concentrated wastewater types (industry, agriculture).
It applies for all plants with filters that a pretreatment is necessary to ensure against
clogging. The pretreatment can be anything from fine screening to hyper-filtration.
9 .2.2 Plants with suspended sludge
The plant type resembles activated sludge plants. The sludge is kept mechanically
stirred or in certain cases stirred through the gasification in the process and the
pumping in of wastewater.
The traditional plant is shown in Fig 9.5 and is called the contact process.
The biological process takes place in a tall tank, 5-10 m, whereas sludge separation
takes place by settling, lamella sedimentation, possibly with preceding degasification or refrigeration, see Fig 9.6.
Degasification or gas stripping prevents or delays the time for the production of
rising sludge as a certain gas production is going to take place after the degasification before the water is sufficiently super saturated for gas bubbles to be formed
Fig 9.5
Contact process, anaerobic wastewater treatment.
290