Selection of a filter press?
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Let me explain the situation first: the company is relatively small, with limited space and funds. . . . :There probably isn’t any space or money for things like sludge thickening tanks. So I’m thinking of using sedimentation followed by direct pressure filtration; I wonder if that’s possible? The design is aimed at treating phosphate wastewater, by using filter presses to settle the solids. There are two types of sediments: lime sludge and flocculent precipitates formed from polyaluminum chloride. For lime sludge, I think a plate and frame filter press can be used. What kind of filter press is suitable for the flocculent precipitate of polyaluminum chloride?
Or please tell me some actual examples or things I need to pay attention to. I can look up information on filter presses from books on my own (I’m not lazy; P).
Without a thickener and relying only on sedimentation tanks, it is difficult to remove the sludge; after a long time of sedimentation, it becomes impossible to remove it at all, and even grabbing it with a grab is challenging.
In factories, plate-and-frame and belt types are used most frequently; both have their advantages and disadvantages. The advantage of the plate-and-frame type is that it results in low sludge moisture content and makes transportation easier, while the disadvantage is that it requires manual operation for opening the plates for cleaning, which involves a lot of work and creates a poor working environment. The advantage of the belt type is automatic pressing and a better working environment, while the disadvantage is that its moisture content is higher than that of the plate-and-frame type. I’m not aware of the current prices; you can inquire with the manufacturer. In the past, we have used the plate and frame filters from Hangzhou Xinyuan as well as the compression units for municipal sewage treatment equipment in Tianjin, and the quality of both was quite good. It’s best to consult the manufacturer for details. However, regardless of the treatment method, it is best to use coagulants and flocculants to reduce the workload on the filter press.
For belt-type concentration integrated filter presses, if there is no space, a vertical concentration tank can be used.
The type of filter press to be used should also take into account the particle size and crystal fineness of the medium.
For the precipitation of phosphate-laden lime sludge, a plate and frame filter should work; if the amount is large, a sedimentation centrifuge is recommended. The two types of precipitates are treated together; the flocs may settle along with the lime precipitate, and plate and frame filtration can be used for this purpose. For flocculation and sedimentation to be handled separately, there may be no suitable method. This post was last edited by YANZE1116 on 2009-3-9 21:42.]
Direct dehydration without concentration will result in the need for a larger dehydrator, which does not save on costs, and the moisture content of the sludge will remain very high! ! ! Consider a concentration and clarification unit that combines both functions!
Mix the two together and then feed them into a filter press; use a filter cloth of a denser type for the filter press
The brother on the 4th floor is absolutely right; sludge concentration is necessary. Although there are filter presses that combine concentration and filtration, their price is more than twice that of belt-type machines with the same processing capacity, and their performance is fairly average in the absence of a concentration tank. Regarding the concentration tank, the owner is worried about the high cost of investment, but this concern is unfounded. Since your plant is small, the amount of water used is likely low, so the concentration tank will also be small. You can consider building a concentration tank made of brick and concrete, as its cost is about half lower than that of one made of steel and concrete. A pool with a volume of 100 cubic meters costs just over 30,000 yuan (including the equipment), so it’s not a large investment. This post was last edited by johncom on 2009-4-12 08:45]
LZ has such equipment, called a belt-type concentration and filter press integrated unit; companies like Yangzhou Tianyu Environmental Protection and Nanjing Lanshen Environmental Protection possess it, but it is very expensive. The best solution is to build a sludge thickening tank; it isn’t costly but is very practical.
It is best to use coagulants and flocculants for treatment in order to reduce the workload on the filter press. If the volume is not large, batch operation can be used. The filter presses in our factory are of the centrifugal type; they have a high degree of automation and a low failure rate, but their price is too high!
A rapid diaphragm filter can be used for limestone precipitation; we have clients who use the same type of equipment. If flocculation is involved, plate and frame filters are not suitable when the concentration is low, as the filtration time will be longer.