In the field of municipal sludge treatment, the plate and frame filter press, as an efficient solid-liquid separation device, is widely used in the sludge dewatering process. However, in the actual operation process, the plate and frame machine often encounters two major thorny problems when pressing sludge - sticking to the filter cloth and the appearance of a "runny core" phenomenon. This not only affects the filtration efficiency but also increases the operating cost and the difficulty of treatment. The emergence of sludge enhancers has provided an effective solution to these problems.
Adhesion of filter cloth: The "Stumbling block" to filtration efficiency
When the plate and frame filter press is in operation, sludge is forced into the filter chamber. Under the action of pressure, water passes through the filter cloth and is discharged, while solid particles remain in the filter chamber to form a filter cake. However, when dealing with sludge of certain special properties, the sludge tends to stick to the filter cloth. The adhered sludge will clog the pores of the filter cloth, increasing the filtration resistance and making it difficult for water to be discharged smoothly, thereby prolonging the filtration time. For instance, some sludges containing a large amount of colloidal substances or organic matter have a relatively high viscosity and are very likely to adhere to the surface of the filter cloth. This not only reduces the filtration efficiency but also increases the frequency and difficulty of cleaning the filter cloth. Frequent cleaning of filter cloth not only consumes a large amount of water resources and manpower, but also shortens the service life of the filter cloth and increases the cost of equipment maintenance.
"Runny heart" phenomenon: The "Killer" of Filter cake quality
The "runny heart" phenomenon refers to the excessive moisture content inside the filter cake, presenting a state similar to thin mud and failing to achieve the expected dehydration effect. There are mainly two reasons for the "runny heart". On the one hand, the particle structure of sludge is fine and uniform, making it difficult to form an effective framework structure to support the discharge of water during the filtration process, resulting in water being retained inside the filter cake. On the other hand, the binding force between the water in the sludge and the solid particles is relatively strong, and it is difficult to separate them by conventional filtration pressure. For instance, some sludge containing high concentrations of chemical agents or microorganisms has a relatively tight combination of internal water and particles, which is prone to the problem of "runny heart". The "runny heart" filter cake not only increases the difficulty of subsequent transportation and disposal, but may also cause secondary pollution and have adverse effects on the environment.
Sludge enhancer: The "Key" to Problem-solving
Sludge enhancer is a kind of chemical agent specially developed for sludge treatment. By changing the physical and chemical properties of sludge, it effectively solves the problems of sludge sticking to the filter cloth and "runny core" in plate and frame press sludge.
From the perspective of solving the problem of adhering filter cloth, sludge enhancers can reduce the viscosity of sludge. It works by undergoing chemical reactions with colloidal substances and organic matter in the sludge, destroying their molecular structure and reducing the interaction forces between sludge particles, thus making it less likely for the sludge to adhere to the filter cloth. For instance, some sludge enhancers contain surfactant components, which can reduce the surface tension of sludge particles, making it easier for the sludge to fall off the filter cloth. In this way, the filtration resistance is reduced, water can be discharged quickly, and the filtration efficiency is significantly improved. Meanwhile, the cleaning frequency of the filter cloth is reduced, its service life is prolonged, and the maintenance cost of the equipment is lowered.
In addressing the "runny heart" issue, sludge enhancers play a unique role. It can improve the particle structure of sludge and form a more stable framework structure between sludge particles. This skeleton structure can provide more channels for water to be discharged and enhance the dewatering performance of sludge. In addition, sludge enhancers can also break the binding force between water and solid particles in sludge, making it easier for water to be separated. For instance, sludge enhancers contain flocculant components, which can cause sludge particles to aggregate into larger flocs, increase the porosity of sludge, and promote the discharge of water. After being treated with the sludge enhancer, the sludge, under the action of the plate and frame filter press, can form a filter cake with a low moisture content and firm texture, effectively solving the problem of "runny heart".
Practical application case: Remarkable results
During the operation of a certain municipal sewage treatment plant, the plate and frame filter press often experiences the phenomenon of filter cloth sticking and "runny core" when treating sludge, resulting in low filtration efficiency and persistently high moisture content in the filter cake. To solve these problems, the factory introduced sludge enhancers for experiments. After adding the sludge efficiency enhancer, the operation effect was significantly improved. The filtration time has been shortened from an average of 4 hours to 2.5 hours, significantly enhancing production efficiency. Meanwhile, the cleaning frequency of the filter cloth has been reduced from three times a day to once a day, and the service life of the filter cloth has been nearly doubled. In terms of filter cake quality, the moisture content of the filter cake has been reduced from the original 75% to below 60%, achieving an ideal dewatering effect. By using sludge enhancers, this sewage treatment plant not only reduces operating costs but also enhances the efficiency and quality of sludge treatment, providing convenience for subsequent transportation and disposal.
The sludge enhancer has a remarkable effect in solving the problems of sludge sticking to the filter cloth and "runny core" in the plate and frame press. It enhances the efficiency of filtration by improving the physical and chemical properties of sludge, reduces operating costs and improves the quality of filter cakes. In the field of municipal sludge treatment, the promotion and application of sludge enhancers have significant practical significance, which is conducive to achieving efficient, environmentally friendly and sustainable development of sludge treatment.