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Residual sludge coming from dimension stones working plants represents a problem for European Stone Industries. The difficulties to opportunely exploit such waste are related to their chemical and physical characteristics. Moreover the management of sludge is subject to periodic updating regulatory developments (DLgs 152/06, DLgs 13/09 and DLgs 61/2012 in Italian legislation) which can complicate their correct management. The topic of the research, financed by Camera di Commercio VCO (Verbano Cusio Ossola—Piedmont Region—NW Italy), is the evaluation of the best methodologies for residual sludge treatment and exploitation. A chemical and physical characterisation on the sludge as such, and on several mixes produced to individuate the more suitable recycled products, was foreseen. Laboratory and in situ tests are in progress (2012–2014). The paper aims to demonstrate that, on the basis of a strict characterisation, appropriate treatment and correct management it is possible to turn residual sludge (waste) into resources (potentially alternative to the natural ones).

Numerous exploited springs (1571) have been investigated in the Turin Province. They have been mapped with a GIS on a new, specially drafted, geolithological map and statistically examined with regard to areal distribution, discharge, use and lithological composition of their catchment basin. One spring every 4 km2 occurs in this area. In detail, the spring density is greater in the mountains (1 spring every nearly 3 km2) than in the plains and in the hills (1 spring every 10–53 km2). These springs are well-distributed in the different altitude ranges, with two peaks at 800–1,100 m and at 140–300 m. They are mostly used for drinking water supply (65 %), irrigation (23.5 %), sanitary use (6 %) and, subordinately (5.5 %), industries, fish farms, production of electric energy and unknown use. The 54.7 % of the springs has discharge lower or equal to 1 l/s, while only the 2.7 % (43 springs) has discharge greater than 10 l/s. A 81 l/day drinking water supply each inhabitant is estimated per capita. The spring areal distribution into the different geolithological units and their discharge values (linked to the aquifer typology) are synthetized. A sample of 28 analyzed springs has bicarbonate to sulfate alkaline-earth facies. Their electric conductivity (100–400 μS/cm) is due to content of bicarbonates (mean value of 100 mg/l) and sulfates (mean value of 15 mg/l). In a single basin (Dora Riparia) the Total Hardness exceeds 25 French Degrees.