There are many factors affecting the flocculation effect, mainly including the type, concentration, amount of flocculant, stirring condition during coagulation treatment, pH value, temperature and its changes, etc. Different countermeasures should be adopted according to the specific situation.

1. Type and dosage of flocculant: Different flocculants should be used for different wastewater. The amount of flocculant affects the effect of flocculation to a large extent. Excessive or insufficient amount will lead to the dispersion and stability of sol particles, so the optimal dosage should be determined through experiments.

2. The influence of stirring and reaction time: After adding a certain flocculant to the wastewater, firstly, the flocculant must be diffused into the water quickly and evenly. After the flocculant is fully dissolved, the generated colloid will form many tiny alum flowers after contacting with the original colloid and suspended matter in the water. This process is also called mixing. The mixing process requires the water flow to generate intense turbulence to fully mix the agent with the water in a relatively fast time. The mixing time generally requires several seconds to 2 minutes.

3. Influence of ph value and alkalinity: ph value has a great influence on the operation of flocculants, so when flocculating wastewater, it is necessary to pay full attention to its effective ph value range. The organic polymer flocculant does not have a strict limit on the pH value, but a small pH value has a greater impact on the flocculation effect of the flocculant. Inorganic flocculants are more sensitive to the pH value of wastewater. Since the hydrolysis reaction of the flocculant continuously generates hydrogen ions, the hydrolysis reaction should be kept fully carried out.

4. Influence of temperature: water temperature also affects the flocculation effect. The hydrolysis reaction of inorganic flocculants is an endothermic reaction. When the water temperature is low, it is not conducive to the hydrolysis of the flocculant. The viscosity of water is also related to the water temperature. If the water temperature is low, the viscosity of the water is large. , resulting in the weakening of the Brownian motion of water molecules, which is not conducive to the destabilization and flocculation of colloids of pollutants in water, so the formation of flocs is not easy. Therefore, more flocculants are used in winter than in summer. The increase of temperature is conducive to the collision between colloids to cause coagulation, but the temperature of more than 90 degrees Celsius will easily cause the flocculant to age or decompose to produce insoluble substances, which will reduce the flocculation effect.