The coagulation treatment of wastewater by polyferric sulfate is mainly through the adsorption and sedimentation of suspended colloidal particles in the water to achieve the purification effect of precipitation and separation. It has the functions of efficient coagulation, dephosphorization, decolorization and deodorization. In the process of dosing and treatment, when we do wastewater coagulation treatment, we often have poor coagulation effect. Why is this? The following analyzes the influencing factors that affect the coagulation of polyferric sulfate.
The influence of water quality factors, first of all, is the PH value of water quality. Taking the selection of polymeric ferric sulfate as an example, when the pH of the water is less than 4, the ferric hydroxide formed by the reaction of polyiron and water will dissolve in the acidic wastewater and exist in the form of iron ions, which cannot play the role of adsorption and bridging. The pH of the water is adjusted to 6.5-7.5, so that it can generate polymerized ferric sulfate to form ferric hydroxide colloid, and then play the role of adsorption and sedimentation. Therefore, different coagulants have different PH values. In the best PH value, polyferric sulfate can dissolve and aggregate the flocs in the water at the fastest speed to achieve the ideal treatment effect.
water temperature effect. There is a close relationship between the hydrolysis temperature and its reaction time. This is because the water temperature is too low will affect the viscosity of the water, reduce the Brownian motion of water molecules, and affect the coagulation of the water body. On the other hand, if the temperature of the water body is too high, the polyferric sulfate flocculant will be damaged and decomposed into insoluble substances. Therefore, the temperature of the water body should not be too high nor too low, generally not lower than 20 ℃, not higher than 90 ℃.
Impurities in water bodies are also a major factor affecting coagulation. The presence of divalent metal ions in water can promote the aggregation of colloidal particles in water, increase the concentration, and promote coagulation. The presence of chloride ions, surfactants and phosphate ions in the water will prevent the coagulation of the coagulant.
In addition to the above-mentioned water quality factors, the poor coagulation effect is also affected by the coagulant itself. For example, the influence of the basic degree of polyferric sulfate, the dosage and the order of dosage. Different water quality has different requirements for coagulants. In order to achieve better treatment effect, it is best to analyze, select and adjust through experiments before use.