Sludge dewatering is an important part of sewage treatment, and polyacrylamide (PAM) as a sludge dewatering agent cannot be replaced by other dehydrating agents. However, many customers find that when using polyacrylamide (PAM) sludge for dewatering, the sludge sticks to the filter cloth or clogs it. There are also situations where the water quality is unclear and the viscosity of the water increases. Through a large number of practice and test tests, Henan Laixing Water Purification will answer in detail the reasons and prevention measures for clogging filter cloth with polyacrylamide (PAM) for sludge dewatering.
Cationic polyacrylamide (CPAM) has good dewatering performance and application effect, and is currently commonly used for sludge dewatering. In the sludge treatment process, polyacrylamide (PAM) needs to be added to adjust the sludge concentration, which can be understood as adding polyacrylamide (PAM) to the sludge to make the sludge in the sludge flocculate quickly, so as to achieve a good dehydration effect during the filtration process. During the sludge dewatering process, sludge sticks to the filter cloth or clogging for the following reasons:
1. The model is wrong, the molecular weight is too high
When the molecular weight of cationic polyacrylamide (CPAM) is too high, the viscosity of the treated sludge will increase. When pressing through the filter cloth, the sludge will block the seepage holes of the filter cloth, resulting in incomplete desilting of the filter cloth or sticking to the filter cloth. Different sludge sources and different filter presses require different types of polyacrylamide (PAM). It is recommended to re-analyze the test selection.
2. Excessive dosage and incomplete dissolution
The amount of polyacrylamide (PAM) is the exact result obtained after the test. If the dose is increased in pursuit of better dehydration effect, not only will the effect not increase, but it will also lead to poor dehydration effect. If the amount is too large, the mud will become viscous, and there will be too much gelatinous sticky substance, which will clog the filter cloth. And the insufficiently dissolved polyacrylamide (PAM) will appear gelatinous substance, which cannot be completely dissolved after adding the slurry, resulting in sticking to the filter cloth during filter pressing. The recommended dosage is subject to the manufacturer's test results and shall not be increased or decreased. When preparing a polyacrylamide (PAM) solution, water should be added to the mixing drum first, then the mixer should be started, and then polyacrylamide (PAM) should be added slowly, evenly, and uniformly along the vortex formed by stirring. According to the volume of the mixing drum, after adding the dosage of the test, continue to stir for no less than 30 minutes to make it completely dissolved. The mixing drum needs to be cleaned regularly. Clean up the undissolved drug lumps at the bottom in time.
3. The flushing water pressure is too low
As the main method of cleaning filter cloths, cleaning water pressure is very important. If the pressure is too low, the remaining sludge on the filter cloth will not be cleaned and the water permeability will be reduced. The sludge sticks to the filter cloth and cannot be cleaned. At the same time, it will also reduce the solid content of the sludge cake, causing the filter cloth to be seriously blocked for a long time, which cannot ensure the normal operation of sludge dewatering. It is recommended to regularly check the operation of sludge dewatering equipment and deal with problems in a timely manner.