Nowadays calcium carbonate has a great importance in different industrial fields and currently there is the opportunity of appreciate the potential value of marble waste and convert it into marketable products. Marble slurry samples, collected from different dimension stone treatment plants in Orosei marble district (Sardinia - Italy), were chemically, physically, mineralogically, and morphologically analyzed and the obtained data were evaluated for compatibility with the marketable micronized CaCO3 specifications required by some industrial sectors, estimating the prospects of recovered CaCO3 utilization. Besides the economic benefits, transforming a waste into an important economic resource involves environmental advantages, due to reduced marble waste landfills, and sustainability promotion

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In this study, the anammox process was applied for the first time to the treatment of ammonium-rich liquid residues produced by the two-stage anaerobic digestion of food waste (2sAD-FW); such residues may represent a significant environmental issue if not properly managed. A granular anammox reactor was fed with a progressively increasing share of partially nitritated 2sAD-FW wastewater. An alternative operating strategy based on partial by-pass of the partial nitritation unit was tested, in order to regulate the influent NO2/NH4 molar ratio without chemical addition. High nitrogen removal efficiency (89±1%) and negligible nitrite discharge rates were achieved, together with high nitrogen removal rate / nitrogen loading rate (NRR/NLR, 97±1%) and stable specific anammox activity (0.42±0.03 gN2-N/gVSS•d). The observed NH4removed/NO2-removed/NO3-produced molar ratio was in agreement with anammox stoichiometry, as confirmed by the low contribution (< 5%) of denitrification to nitrogen removal. Moreover, the possibility of using digital color characterization of granular biomass as a novel, simple tool for the monitoring of anammox biomass enrichment and process performance was investigated under dynamic conditions, using real wastewater: changes in granule color correlated well with the increasing share of 2sAD-FW wastewater in the influent (R 2 =83%), as well as with the decrease of anammox biomass abundance in the reactor (R 2 =68%). The results suggest that anammox may be successfully integrated into a 2sAD-FW system, thus enhancing its environmental sustainability.

Underground quarrying is rarely adopted for granite extraction due to the difficulties in the implementation of traditional technologies (drilling and explosive). As alternative to drilling and explosive, the combination of diamond wire and water jet seems to be the most promising available technology. The cutting performance achievable with the water jet technology depends on the operative parameters, the material characteristics and the state of stress within the rock massif. To assess the effect of the state of stress on the cutting rate, laboratory tests have been performed with an oscillating water jet machine on granite samples subjected to a static load. The stress distribution in the layer of rock to be removed has been evaluated by numerical simulation with the FLAC code (Fast Lagrangian Analysis of Continua). The correlation between the results of the cutting tests and the numerical models of the rock samples has been inferred. Starting from a conceptual model, which theoretically describes the relationship between the cutting rate and the stress, a step function was defined that indicates the ranges of stress where predefined values of the cutting rate are workable.