The effluent phosphorus of sewage treatment plant substandard?

01 biological phosphorus removal mechanism.

Phosphorus removal from wastewater is a kind of phosphorus absorption phenomenon.Under the condition of anaerobic conditions, the phosphorus is released under aerobic conditions.After entering the aerobic zone, the PHB can be decomposed by polyp bacteria, and a large amount of energy can be released for the growth and reproduction of phosphorus.

The phosphorus absorbed by microorganisms under aerobic conditions is much higher than that released under anaerobic conditions.Because the system often emits the residual sludge, the phosphorus that is ingested by the bacteria will also discharge the system, thus obtaining a better phosphorus removal effect.

02 factors affecting phosphorus removal.

1. Dissolved oxygen.

First, strict anaerobic environment must be controlled in anaerobic zone.This is directly related to the growth status, the ability to release phosphorus and the ability to synthesize PBH using organic matrix.

The second is to provide sufficient dissolved oxygen in the aerobic zone.In order to meet the degradation of PHB stored by polyp, sufficient energy is released for the use of excessive phosphorus, so as to effectively absorb phosphorus from wastewater.

The DO of normal anaerobic section should be strictly controlled under 0.2mg/L, and the DO of the two aerobic segments should be controlled above 2mg/L.

2. Nitrate content.

The presence of nitrate nitrogen also depletes the organic matrix and inhibits the release of phosphorus, which in turn affects the absorption of phosphorus under aerobic conditions.In addition, there will be part of the nitrate nitrogen as electron acceptor for denitrifying phosphorus accumulating, thus affecting the fermented product as electron acceptor for fermentation to produce acid, inhibit the release of phosphorus and phosphorus accumulating p-uptake capability and PBH synthesis ability.

3, temperature,

In general, within the scope of the 5 ~ 30 ℃, good phosphorus removal effect can be received

4, PH

When the PH value is 6~8, the release of phosphorus is stable.

5. BOD5 load and organic properties.

It is generally believed that the ideal dephosphorization effect can be achieved only when the water inlet BOD5/TP is greater than 15.For this purpose, it is possible to use partial water intake and the method of crossing the initial sink to obtain the BOD5 amount needed for phosphorus removal.

6, sludge age

In general, the age of the biological treatment system with phosphorus removal is controlled at 3.5~7d.