Types and functions of stabilization ponds

Stabilization ponds can be divided into four types: aerobic ponds, facultative ponds, aeration ponds and anaerobic ponds according to the predominance of microbial species and corresponding biochemical reactions
.

(1) Aerobic pond The water depth of aerobic pond is relatively shallow, generally 0.
3-0.
5m.
It is an oxidation pond that mainly relies on the photosynthesis of algae in the pond to supply oxygen
.

Sunlight can penetrate directly to the bottom of the pond, and the algae grow vigorously.

According to the level of organic load, aerobic ponds can be divided into low-rate aerobic ponds, high-rate aerobic ponds and advanced treatment ponds
.

Low-rate aerobic ponds reduce the load by controlling the depth of the ponds, and are often used to treat dissolved organic wastewater and the effluent of urban secondary treatment plants

(2) Facultative ponds The water depth of the facultative ponds is generally 1.
5-2m, and there are both aerobic and anaerobic biochemical reactions in the pond
.

In the upper water layer, algae photosynthesis is vigorous during the day, and the pond water maintains an aerobic state, and its purification capacity and various operating indicators are the same as the aerobic pond; at night, the algae photosynthesis stops, and atmospheric reoxygenation is lower than the oxygen consumption in the pond.

(3) The aeration pond is equipped with mechanical aeration or hydraulic aerator on the oxidation pond, in order to promote the action of the pond surface and oxygen, the pond water can be mixed to different degrees and maintain aerobic or facultative state
.

The organic load and removal rate of the aeration pond are relatively high, the area is small, but the operating cost is high, and the concentration of suspended solids in the effluent is high.

(4) Anaerobic pond The water depth of anaerobic pond is generally above 2.
5m, and the deepest can reach 4~5m.
It is a kind of biological pond with high organic load and mainly anaerobic decomposition
.

When the oxygen consumption in the pond exceeds the algae and the atmosphere is reoxygenated, the anaerobic pond will make the whole pond in an anaerobic decomposition state

The main performance of the above four types of oxidation ponds are listed in Table 8-1
.

Table 8-1 Main performance of various stabilization ponds

Each performance in the table is controlled by various factors such as sunlight radiation value, temperature, nutrients and poisons
.

Therefore, its specific value also varies with latitude, weather conditions and water quality