What are the PAM pilot-scale testing methods and evaluation methods?

Sludge dewatering or flocculation? It’s available on Baidu

PAM is a coagulant aid, used in combination with coagulants; it is directly related to the type of coagulant, the amount added, water temperature, mixing intensity, and the SS concentration of the water sample.

Using the characteristic 1PAM, suspended substances can be flocculated through electro-neutralization and bridge adsorption. 2 can exert adhesive effects through mechanical, physical, and chemical actions. 3PAM can effectively reduce the frictional resistance of fluids; adding a small amount of PAM to water can reduce this resistance by 50–80%. 4: PAM has thickening properties under both neutral and acidic conditions; it is prone to hydrolysis when the pH value is above 10. When it is in a semi-network structure, thickening will be more pronounced. Instructions for the amount of polyacrylamide to be used: 1. The amount of cationic polyacrylamide used for coal washing can be set between 30 kilograms and 110 kilograms ； The wastewater usage in the chemical industry is generally between 50 and 120 kilograms ； The wastewater from the dyeing and printing industry as well as that from the papermaking industry is the most difficult to treat. It is advisable to increase the amount used, with 100 to 300 kilograms being a reasonable range; for the wastewater from the electroplating industry and ordinary industrial uses, the amount should not exceed 50 kilograms. Note: (The usage amounts for these industries are all per thousand tons of wastewater.) 2. Depending on the treatment method, different flocculants are used for sludge removal in domestic wastewater. If the main treatment process employs biochemical methods, that is, sludge dewatering of residual sludge (which may contain some primary sediment), only cationic PAM is required as a sludge dewatering agent. If physical and chemical methods are used in the main processing steps, such as primary intensification or magnetic separation, PAC is generally added first for conditioning, followed by anionic flocculants, and finally cationic flocculants for dewatering. The specific dosage should be determined based on the quality of the wastewater. There are also many sewage treatment plants where sludge dewatering can be achieved by simply adding PAC or other inorganic coagulants; this method is widely used in plate and frame filter presses, especially in electronics factories or small-scale sewage treatment plants. When used as a sludge dewatering agent, PAM generally needs to be mixed with water at a ratio of 0.1%–0.2%. After being dissolved into a glue-like liquid, it is then added to the sludge for mixed treatment. The ratio to the sludge is generally 5%–10%, with some values being even lower; this depends on the concentration of the sludge. It is best to determine the optimal dosage and the appropriate model through laboratory tests on site. The treatment efficiency of sludge varies depending on different types of sludge, different chemicals used, different equipment, and different management levels. 3. Cationic polyacrylamide is used as a sludge dewatering agent in wastewater treatment plants. During communication with clients, they often ask about the amount of sludge dewatering agent to be used in the process of dewatering sewage sludge. To determine the dosage of sludge dewatering agents with relative accuracy, it is first necessary to understand various parameters such as the moisture content of the sludge, the moisture content of the sludge cake, the amount of sludge fed in, the amount of chemical added, and the concentration of the mixture. Sludge moisture content: The percentage of the weight of water contained in the sludge relative to the total weight of the sludge is known as the sludge moisture content. Sludge cake moisture content: The percentage of the weight of water contained in the dewatered sludge, that is, the sludge cake, relative to the total weight of the sludge is known as the sludge cake moisture content. Calculations are also required using the following formulas: 1. Dosage amount in mg/L = dosage mass / treated water volume / concentration of the chemical used. 2. Dosage amount required for a given treated water volume = treated water volume in m3/h * dosage amount in g/m3. 3. Amount of dry sludge = treated water volume * 【(1 – moisture content of sludge) / (1 – moisture content of sludge cake)». 4. Chemical consumption per ton of dry sludge in g/m3 = dosage amount / amount of dry sludge

Principle of flocculation: When PAM is used for flocculation, it is related to the surface properties of the substances to be flocculated, particularly their zeta potential, viscosity, turbidity, and the pH value of the suspension. The zeta potential on the particle surface is what prevents aggregation; by adding PAM with an opposite surface charge, this zeta potential can be reduced rapidly, thereby facilitating aggregation. Adsorption bridging: PAM molecular chains are attached to the surfaces of different particles, and polymer bridges are formed between these particles, causing the particles to aggregate and settle. Surface adsorption: The various adsorptions of particles onto the polar groups on PAM molecules. Reinforcement effect: The PAM molecular chains bind the dispersed phase together through various mechanical, physical, and chemical mechanisms, forming a network that thereby provides reinforcement.

Key technical specifications of polyacrylamine: Type – Anionic, Cationic, Non-ionic, Amphoteric. Molecular weight range – 5 million to 20 million. Degree of ionization – Not specified. Price – 7,500–19,500 yuan per ton, 19,500–35,000 yuan per ton, 7,500–18,000 yuan per ton, 7,500–19,000 yuan per ton. Packaging – 25KG per bag, 25KG per bag, 25KG per bag, 25KG per bag

Storage, transportation, and usage methods of polyacrylamide, as well as precautions: 1. It must not be mixed with additives from other brands without conducting experiments first； 2. The water used for dilution and the containers must be kept clean ； 3. This product should be stored in a cool, well-ventilated place, away from direct sunlight ； 4. This product is a chemical preparation and is not edible. Contamination on the human body and clothing can be removed by washing with water ； 5. Storage period: three months.