The full article from "DISCOVERY STONE" about water recycling and the stone industry

In Australia it is vitally important to find cost effective and intelligent solutions to the problems of excessive water consumption in all areas of life, but especially within industries. The stone industry is one in particular that produces large amounts of wastewater while cutting and polishing natural and engineered stone products.

The process for the transformation of natural stone and engineered stone is almost always carried out using water as a cooling, cleansing and carrying agent to remove waste. 
It is obvious then, that huge volumes of water are needed during the process of transformation. Furthermore during this process the water gets charged with macroscopic and microscopic particles as a result of the various operations (cutting, polishing, profiling etc). This water then cannot be reused (due to residual matter) unless it is clarified.

If we consider water consumption over the space of one working year, cost is very high (for instance: a traditional bridge saw and an edge polisher require around one hundred l/m). If we take an average use at 50%, that is we suppose the machines actually work only 12 days out of every 25 a month, 8 hours a day, then the total consumption of water for that year is around 6 million litres. We can see the cost is very high if we multiply this consumption by the cost of a litre of water.

The water that comes out of the industrial process presents us with another problem as it not only contains stone particles, but also particles from the diamond tools. Obviously this industrial waste has to be disposed of by authorised companies and the cost of disposal will depend on whether we dispose of the water with the sludge still in it, or of the dry sludge alone. In this second case the cost is much less.

The process of separating solid particles in suspensions in the water is called water clarification and sludge dehydration. This process allows the user to recycle virtually 100% of the water coming from the industrial process. Usually the treatment of water takes place by means of chemical accelerators (flocculants, coagulants) that are chosen depending on the type of water to clarify.  Obviously the clarified water coming out of the plant is never equal to the total amount of water introduced from the mains in that there is some loss of volume during the whole process. Therefore, from time to time, water needs to be added from the mains but still the clarification plant has given us a water and money saving, in full compliance with environmental laws.