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whereas facultative stabilization ponds maintain an aerobic surface habitat above an
anaerobic zone. Maturation ponds have aerobic conditions from the bottom to the
surface.
Facultative Pond
Facultative ponds or lagoons are designed in such a way that it favours growth of
facultative bacteria that are capable of living in both aerobic and anaerobic conditions.
The upper portion of facultative pond will be dominated by aerobic bacteria, while the
bottom portion is dominated by anaerobic bacteria. The depth of the pond will be
more than that of oxidation pond to reduce space requirement. A series of ponds connected in series and parallel will be built so that the wastewater will undergo changes
in each stage. This method can be used in frost-free area with consistently cool climate. The settled solid will not be removed continuously as in primary sedimentation
tank and hence required periodic maintenance to remove accumulated sludge.
Anaerobic Pond
Anaerobic ponds will usually have a depth of 3.0–5.0 m. Depending on the climatic
condition and loading these ponds can remove between 50% and 60% of the influent organic load. Sludge gathered at the bottom needs to be removed periodically
every few years.
5.2.2.10 Aerated Lagoon
An aerated lagoon consists of a pond with artificial aeration to enhance the biological oxidation of wastewaters.
5.2.2.11 Activated Sludge Process
The activated sludge process contains an aeration tank (Fig. 5.9) followed by a settling tank. Part of sludge separated in sedimentation tank is recycled to aeration tank
to maintain active biomass (microorganism, which have been acclimatized and
active to disintegrate the organic matter entering the system).
5.2.2.12 Trickling Filter
A trickling filter consists of a fixed bed of porous media over which wastewater is
sprinkled to form layer of microorganism on media followed by settling tank to
settle the pealed biomass that enters outgoing effluent.
5 Water and Wastewater Treatment
whereas facultative stabilization ponds maintain an aerobic surface habitat above an
anaerobic zone. Maturation ponds have aerobic conditions from the bottom to the
surface.
Facultative Pond
Facultative ponds or lagoons are designed in such a way that it favours growth of
facultative bacteria that are capable of living in both aerobic and anaerobic conditions.
The upper portion of facultative pond will be dominated by aerobic bacteria, while the
bottom portion is dominated by anaerobic bacteria. The depth of the pond will be
more than that of oxidation pond to reduce space requirement. A series of ponds connected in series and parallel will be built so that the wastewater will undergo changes
in each stage. This method can be used in frost-free area with consistently cool climate. The settled solid will not be removed continuously as in primary sedimentation
tank and hence required periodic maintenance to remove accumulated sludge.
Anaerobic Pond
Anaerobic ponds will usually have a depth of 3.0–5.0 m. Depending on the climatic
condition and loading these ponds can remove between 50% and 60% of the influent organic load. Sludge gathered at the bottom needs to be removed periodically
every few years.
5.2.2.10 Aerated Lagoon
An aerated lagoon consists of a pond with artificial aeration to enhance the biological oxidation of wastewaters.
5.2.2.11 Activated Sludge Process
The activated sludge process contains an aeration tank (Fig. 5.9) followed by a settling tank. Part of sludge separated in sedimentation tank is recycled to aeration tank
to maintain active biomass (microorganism, which have been acclimatized and
active to disintegrate the organic matter entering the system).
5.2.2.12 Trickling Filter
A trickling filter consists of a fixed bed of porous media over which wastewater is
sprinkled to form layer of microorganism on media followed by settling tank to
settle the pealed biomass that enters outgoing effluent.
5 Water and Wastewater Treatment