In urban pile driving or shield tunnel construction, a large amount of sewage is generated in shield tunneling construction, tunnel segment cleaning, grouting pipe cleaning, mortar bucket cleaning and underground flushing, especially when the water-rich strata encounter gushing, a large amount of highly concentrated mud water will be produced. Sewage contains a large number of kaolin mud particles, cement, etc. Ground application wastewater is mainly mortar mixing, washing. Sewage from vehicles, road flushing, toilet flushing, etc.
According to the long-term experimental summary of Shouxin Environmental Protection of our company, by adding flocculant PAC and polyacrylamide PAM into the water samples taken from underground without pretreatment, the sewage can be completely treated clean after stirring and precipitation, and can meet the reuse standard.
The role of polyacrylamide precipitator in pile shield mud is adsorption, bridging, net trapping and electric neutralization, the role of polyaluminum chloride is to produce strong electric neutralization reaction to colloids in water, adsorption bridging, etc. Some difficult mud even need to add lime calcium oxide for coagulation or dilution treatment.
In building piling shield, it is necessary to choose anionic polyacrylamide or cationic acid according to the characteristics of mud. The mud in different areas should be tested to select the suitable polyacrylamide products for customers to use on site. At present, most of the mud is treated with anionic polyacrylamide. According to the long-term experiment of our company, it is suitable for mud treatment with anionic polyacrylamide hydrolysis degree between 25-40%, molecular weight between 12 million and 18 million, and the mud flocculation treatment effect is better.
Polyacrylamide (PAM) is a linear polymer, chemical formula is (C3H5NO) N. It is a hard glassy solid at room temperature. The products are liquid glue, latex and white powder particles, translucent beads and flakes. Good thermal stability. Can be dissolved in water in any proportion, aqueous solution is uniform transparent liquid. After long-term storage, the solution viscosity will decrease due to slow degradation of polymer, especially when the storage conditions are poor.  Polyacrylamide, as lubricant, suspension agent, clay stabilizer, oil displacement agent, water loss reducer and thickener, has been widely used in drilling, acidification, fracturing, water plugging, cementing and secondary oil recovery, tertiary oil recovery. It is a very important oil field chemical.Learn more
Polyferric sulfate is a kind of inorganic polymer coagulant with superior performance. It is a light yellow amorphous powdery solid and easily soluble in water. 10% (mass) aqueous solution is red-brown transparent solution and hygroscopic. Polyferric sulfate is widely used in drinking water, industrial water, all kinds of industrial waste water, municipal sewage, sludge dewatering purification treatment.Learn more