Improve the coagulation effect Adding polyaluminium chloride when adding coagulant What is the role? Improve the coagulation effect Adding polyaluminium chloride when adding coagulant What is the role? Polyaluminum chloride is a kind of macromolecule polymer, because of its larger molecular weight, it has strong ability to adsorb clay colloids and form larger flocs. In order to reduce the coagulant polyaluminum chloride dosage, improve the coagulation effect, often adding polyaluminum chloride at the same time, adding coagulant. Coagulant commonly used in the following categories: Oxidants: such as liquid chlorine and bleach Raw water, such as organic humus or algae content, high chroma, although the turbidity is not very high, often in the coagulation process dosing A large number of polyaluminum chloride. In order to destroy the organic colloids in the raw water and kill the algae, oxygen can be added before adding the polyaluminum chloride to improve the coagulation effect and reduce the polyaluminum chloride dosage. Acid and alkali: such as lime and caustic soda When the alkalinity of raw water can not meet the needs of polyaluminum chloride reaction, alkali treatment must be carried out. Base dosage, can be used to control the PH value to be determined. Lime quality requirements of calcium oxide 70% -80%. Because lime easily absorb moisture and carbon dioxide in the air and deterioration, the content of calcium oxide will be reduced to 20% or less, it is better to buy now. The advantage of caustic soda is more stable quality, generally more than 92% sodium hydroxide content, the use of more convenient. However, caustic soda easy deliquescence (quality is not affected), corrosive, the price is more expensive. Polymer compounds: such as sodium alginate, polyacrylamide, bone glue and other raw materials of sodium alginate seaweed or kelp. It is better at dealing with high turbidity water than low turbidity water, but at a higher cost. Polyacrylamide is currently a good coagulant for treating high turbidity water. It can also be used as a coagulant. Gum and Poly aluminum chloride coagulant mixed with good effect; also with PAC ferric chloride, polyferric sulfate mixed use. It should be noted that the polymer compound coagulant is still used in rural water supply is still low. Skeleton materials for increasing alum and coagulant for ameliorating alum: eg activated water glass. When the raw water turbidity is low, suspended solids content is low, the water temperature is low, the use of activated water glass as coagulant, can promote the floc solid, increase weight, easy to sink. Water glass activation method is to dubbed it 3% -5% aqueous solution, slowly adding industrial sulfuric acid, to be side plus side stirring, the solution alkalinity control 1200 mg / l to 1500 mg / l appropriate. Activation time of about 4 hours, the solution should be emulsified state, if the block becomes frozen failure. Water glass dosage and raw water turbidity, PH value and the water content of silica, the choice should be through experiments before, choose the best dose; dosing point should be selected before the polyaluminum dosing point. The selection of coagulant should be based on the specific circumstances of water quality, proved effective through experiments, combined with the supply of pharmaceuticals and the price for technical and economic comparison to determine the selected active ingredients and toxic substances content should meet the required product quality standards.