The agents that can be used for deep dewatering of paper mill sludge mainly include but are not limited to the following:
Polyacrylamide (PAM) :
Polyacrylamide is a kind of high polymer dehydrating agent, which has strong hydrophilicity and good flocculation performance.
According to ionic properties, PAM can be divided into anionic, cationic and non-ionic types. In the process of deep dewatering of sludge in paper mill, cationic PAM is often selected because it can effectively reduce the settling volume of sludge (SV30) and improve the settling performance of sludge.
Polyaluminum chloride (PAC) :
Polyaluminum chloride is also a commonly used sludge dewatering agent, which can quickly form a large floc in the sludge and contribute to the subsequent dewatering treatment.
When used in combination with PAM, PAC first combines with sludge to form floc, and then PAM further increases the floc of sludge through net catching, rolling, adsorption and bridging, forming a large floc that can self-settle, thereby improving the dehydration efficiency.
Biological flocculant:
Biological flocculant is a new sludge dewatering agent, which uses microorganisms or their metabolites as flocculants, and has the advantages of environmental protection, non-toxic, biodegradable and so on.
Although the application of biological flocculants in the deep dewatering of paper mill sludge may not be as extensive as that of traditional agents, its environmental protection characteristics deserve attention and promotion.
Other agents:
In addition to the above agents, alum, lime, ferrous sulfate, polyferric sulfate and other agents can also be used for deep dewatering of paper mill sludge.
These agents have their own characteristics, and the specific selection should be considered according to the nature of sludge, treatment scale, cost and other factors.
In the process of deep dewatering of sludge in paper mill, the selection of chemical agents and the matching degree of sludge dewatering equipment are very important. For example, when using a plate and frame filter press for deep dehydration, it is necessary to ensure that the large flocs formed by the conditioned sludge can pass smoothly through the filter cloth and effectively discharge water. In addition, the operator also needs to strictly control the dissolution ratio of the reagent and the way of mixing the reaction to ensure the effective use of the reagent and avoid waste.
In summary, there are a variety of agents that can be used for deep dewatering of paper mill sludge, and the specific selection should be comprehensively considered according to the actual situation.