Is a filter press needed in stone masonry?

Systems for purifying production water used in processing processes for stone, glass or ceramics, for example, focus on precipitating as many solids as possible from the water. The process water required for tool cooling in machining processes must be free of as many impurities as possible that can damage the tools or the material being machined. In the stone and glass industry, it is not required to obtain clear water, that is, perfectly transparent water. Slightly cloudy water is still good process water. So the water treatment plant used there must be effective and reliable enough to filter a great deal of contaminants from the water. This is important because the solids circulating in the process water are hard and sharp, and thus dangerous to the treated surfaces, which can be scratched.

Process water treatment plants for stonemasons and glassblowers are usually based on vertical sedimentation supported by appropriately selected flocculants and coagulants. Suspended solids in water accumulate at the bottom of sedimentators, also called vertical settlers or clarifiers. Such a thickened suspension, due to the material in the water, is very heavy, which leads to spontaneous further thickening at the bottom of the settling tank. In order to prevent the sludge from binding or clumping, and thus clogging the settling tank, the accumulated suspended solids must be removed from it regularly. The process of emptying such a settling tank (clarifier) is gravity draining by the lower valve of the mud accumulated at the bottom.

The sludge removed from the treatment plant is a semi-liquid substance so and difficult to further collect or handle. Such a semi-liquid sludge of the consistency of, for example. The cream must be dried so that it can be further processed or disposed of. The method of drying, on the other hand, is defined by the amount and moisture content of the sludge. Due to the nature of stone processing and the amount of grinded (ground) stone dust that is produced during the work, the amounts are quite large. For small filtration plants, where the waste is less than 1m3 / week, you can deal with its drying in special filter bags. Such bags are also disposable packaging for this waste. Such a method of sludge dewatering is used by semi-automatic water treatment plants manufactured by Silkam. However, with larger amounts of sludge, such solutions are already becoming inefficient. They require a significant amount of space to collect and dry the bags. In addition, they are very labor-intensive which is related to the need for frequent replacement of bags. With larger amounts of mud sludge, filter presses are already becoming necessary for drying.

Chamber filter presses manufactured by Silkam, are designed specifically to handle heavy stone, glass or concrete sludge. The task of such a filter press is to compress and dewater the sludge thickened in the settling tanks. The size of the device depends on the amount of sludge to be dewatered and the degree of compaction of this sludge. The size of the filter press is also selected according to the types of sludge and flocculants used.

The filter press manufactured by Silkam, is an automatic device, and thus the need for human supervision of its operation is reduced to a minimum. Thanks to its use, sediment accumulated in sedimentators is constantly and regularly removed from them. Most importantly, however, is the fact that the use of a filter press deprives the accumulated sludge of excess water in a short process. Compressed sludge can have a moisture content as low as 25%. Such dewatering of the sludge makes it hard, and it can be accumulated on heaps or transported by standard transportation means designed for bulk materials. Typically, the filter press is set up so that a container for the compressed sludge can be placed underneath it.

From an economic point of view, the use of a chamber filter press is justified in companies where sludge (sludge) is generated in quantities of more than 1m3/week. For smaller amounts of sludge, however, it is still more advantageous to dewater or dry the mud in filter bags. This is mainly due to the price difference between treatment plants with and without a press. The capacities of filter presses designed for use in quarrying reach up to several m3 per hour of dewatered sludge. In a production facility where the sludge generated is more than 1m3/day, the only reasonable way to dry it is to use a press. Thus, a complete water treatment plant provides continuous filtration of process water in a closed circuit, moreover, when it is equipped with a filter press, it additionally provides drying of solids precipitated from the water.

So is a filter press necessary? Definitely yes if our facility produces larger amounts of waste. Its use, in addition to providing dried waste, also significantly reduces the amount of labor, that is, time spent operating the device.