The dosing stage of flocculants in wastewater treatment

Wastewater treatment is typically divided into stages such as pretreatment, primary treatment, and secondary treatment. The addition of flocculants is primarily concentrated in the primary treatment stage, with some processes also incorporating auxiliary flocculant dosing during pretreatment or advanced treatment. Specific applications are as follows: 1. Primary treatment stage (core dosing point) Scenario: After entering the primary sedimentation tank, sewage is treated by adding flocculants (such as polyaluminium chloride and polyacrylamide). These flocculants, through their charge neutralization and adsorption bridging effects, cause suspended particles and colloidal impurities to aggregate into large flocs. Function: Accelerate solid sedimentation, significantly reduce wastewater turbidity, SS (suspended solids), and part of COD (chemical oxygen demand), thereby reducing the load on subsequent biochemical treatment. 2. Preprocessing stage (auxiliary input point) Scenario: If the concentration of suspended solids in the raw water is extremely high (such as industrial wastewater), a small amount of flocculant can be added in advance after screening and regulation in the pool to initially coagulate large particles of impurities. Function: Prevent subsequent pipeline blockages and enhance primary treatment efficiency. 3. Advanced Treatment Stage (Specific Process Addition Point) Scenario: Before processes such as membrane treatment and advanced oxidation, if the turbidity of the effluent does not meet the standard, flocculant can be added for secondary flocculation. Function: To ensure the operational stability of precision processing equipment (such as membrane modules) and prevent contaminants from blocking the membrane pores. Key points of dosing: Water quality adaptation: Select chemicals based on the pH value and type of pollutants in the wastewater (e.g., iron salts for alkaline wastewater, aluminum salts for acidic wastewater). Concentration control: Determine the optimal dosage through beaker experiments to avoid excessive dosage leading to viscous water or increased costs. Process synergy: Flocculation is often combined with coagulation and sedimentation processes to form an integrated “coagulation-flocculation-sedimentation” workflow, enhancing treatment efficiency. The scientific dosing of flocculants is a crucial step in solid-liquid separation in wastewater treatment. The dosing point needs to be flexibly adjusted based on water quality characteristics and process objectives, in order to achieve a balance between efficient purification and cost optimization. The main products of flocculant manufacturer Xinhuan Water Treatment are: White polyaluminium chloride (food grade), drinking grade polyaluminium chloride, industrial grade polyaluminium chloride, anionic polyacrylamide, cationic polyacrylamide, nonionic polyacrylamide, petroleum recycling polyacrylamide, oil recovery polyacrylamide, polyacrylamide, polymer flocculant polymer flocculation coagulant, polymeric ferrous sulphate, polymerized iron and aluminium chloride, and other water treatment chemicals. Welcome customers to write to us to negotiate business! Tel/WhatsApp：86 19139972558 Email：Sunny@xhwtm.com Contact:Sunny