Well,

Chemical conditioning:

There are many chemicals used in sludge conditioning (flocculation-coagulation), including sulfuric acid, alum, chlorinated copper sulphate, iron sulphate and iron chloride alone with or without lime. Lime alone or iron chloride may be used alone. In the adaptation of the sludge and the iron chloride alone, it is used to adapt activated sludge.

Adding chemicals to the sludge increases or decreases the pH value and allows the small particles to be aggregated into larger molecules and can be removed more quickly. Here, the coagulation surely affected by gases, but those gases may not exist in solution always and at the same time, where aeration process vanish the most impact of gases.

Regards

Coagulants are of different nature and its efficiency depends on water pH. For example Alum work in alkaline pH. Therefore Ammoni will have positive effect on coagulation. CO2 produce corbonic acid

CO2 + H2O = H2CO3

Its effect will be negative.

Hydrogen sulfide is slightly soluble in water and acts as a weak acid (pKa = 6.9 in 0.01–0.1 mol/litre solutions at 18 °C), giving the hydrosulfide ion HS-(also written SH−). So it will also discourage the process of coagulation, if Alam is used as coagulants.

Oxygen will have no effect on coagulation.

Gentleman:

Your feedback is greatly appreciated. The explanation helps me to understand why aerated fresh (de stratified) water bodies tend to use less coagulants and chlorine for oxidation and disinfection.

I agree with answer Nafees Mohammad "

Coagulants are of different nature and its efficiency depends on water pH. For example Alum work in alkaline pH. Therefore Ammoni will have positive effect on coagulation. CO2 produce corbonic acid

CO2 + H2O = H2CO3

Its effect will be negative.

Hydrogen sulfide is slightly soluble in water and acts as a weak acid (pKa = 6.9 in 0.01–0.1 mol/litre solutions at 18 °C), giving the hydrosulfide ion HS-(also written SH−). So it will also discourage the process of coagulation, if Alam is used as coagulants.

Oxygen will have no effect on coagulation".

Well,

Dear Carlos

The second stage of treatment is sludge digestion where the purpose of sludge digestion is to destroy or disassemble volatile organic matter and convert it into a stable or inert product.

In the case of aerial digestion, the air is mechanically prepared (surface fans) to help complete the process of dismantling the remaining organic solids. Aerobic digestion is specifically used to treat activated sludge and the surface water collected on the surface of the digestion is again re-treated because it is highly polluted. Intermittently as in small stations usually or continuously as in large stations. Good operation of the ventilation basin helps to obtain bacterial clusters called coagulation. Other bacteria remain free within the water medium. This puff consists of the accumulation of non-living organic polymers that are released from the bacteria and this has a porous structure with huge holes capable of fighting the shear forces resulting from the movement of water during ventilation.

Regards .

REDOX reaction

The use of coagulants are of different nature and its efficiency depends on water pH I think that the use less coagulants and chlorine for oxidation and disinfection is acceptable.

Hello,

This paper may helps!

https://doi.org/10.1007/s13762-022-04309-2