Although most of the sludge dewatering methods used are plate-chamber filter mechanical pressure drying, according to the characteristics of different sludge, chemical conditioning can make the degree of moisture in the sludge particles become free water so that the sludge is Mechanical dehydration is twice the result with half the effort. Therefore, it is particularly important to understand the classification and source of sludge.
1. The nature of the sludge
Primary sedimentation sludge
This sludge comes from the primary sedimentation tank, and the nature of the sludge varies with the composition of the wastewater. Such as domestic sludge and industrial sludge, the characteristics of the sludge produced at this stage are quite different.
Residual activated sludge and humic sludge
The sludge in the secondary sedimentation tank after the sludge is treated by the activated sludge method and the biofilm method is called the remaining activated sludge and the humic sludge, respectively.
The sludge that has been digested and stabilized, such as the primary sedimentation sludge, excess activated sludge, and humic sludge, is called digested sludge.
Sludge is produced by chemical methods such as coagulation and chemical precipitation.
Organic sludge contains high organic matter, including activated sludge, biofilm, digested sludge after anaerobic digestion, pumping sludge, and sludge formed by the precipitation of solid-phase organic pollutants in wastewater.
The main component is inorganic matter, such as the sediments of wastewater using lime to neutralize sedimentation, coagulation sedimentation, and chemical sedimentation.
2. Source of sludge
It mainly refers to the sludge produced by sewage treatment plants and municipal facilities. This type of sludge is the source of sludge in our country.
Refers to the sludge from the drainage collection system.
River and lake silt
Silt from rivers and lakes. In order to make the city more beautiful, many places have begun to carry out river and lake silt treatment.
Sludge from electroplating factories, leather factories, printing and dyeing factories, paper mills, oil mining, and other places. Because of the complex composition and strong pollution of these sludge, it is necessary to strictly abide by the relevant national laws and regulations during treatment.
3. Add medicine
1) Polymer flocculant, PAM, after being hydrolyzed and matured, is fully stirred with the sludge and pumped to the filter press for dehydration.
2) Adding lime and poly ferric sulfate can also play a role in filtering aid. However, the amount of sludge will increase by about 30%, and the effluent will be alkaline due to the action of lime, which is not conducive to the next treatment of sludge. This sludge can only be landfilled.
3) Add an appropriate amount of coagulant, coagulant, and other chemical agents to the sludge. The main function is particle flocculation. The direct cause of the inability of the filter press to dry is due to the small particles and high viscosity of the sludge, which block the filter cloth and cause difficulties in dewatering. You can try to put quicklime and other conditioning sludge properties.
4. Working principle of chamber filter press
The chamber filter press is firstly positive pressure dehydration, also called slurry dehydration, that is, a certain number of filter plates are tightly arranged in a row under the action of strong mechanical force, and a filter chamber is formed between the filter plate surface and the filter plate surface. The filter material is sent into the filter chamber under strong positive pressure. The solid part of the filter material entering the filter chamber is intercepted by the filter medium (such as filter cloth) to form a filter cake, and the liquid part passes through the filter medium and is discharged from the filter chamber to achieve solid The purpose of liquid separation. The moisture content is an important indicator of the degree of sludge treatment. The moisture content directly affects the difficulty of enterprise transportation and later disposal, and the sludge with high moisture content is prone to odor, permeate, etc., causing secondary pollution.
In the chamber filter press, chemicals are added before the sludge is processed. The appropriate amount of coagulant and coagulant are added to improve the filtration performance of the slurry and shorten the filtration time. After the slurry is added with a flocculant, some organic molecules will gather together to form a floc, and the degree of dispersion is reduced, thereby improving the filterability. If you want to know more about the chamber filter press, please contact online customer service or leave a message.
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