This work analyzes the surfaces obtained in Alloy 718 when they are milled by Abrasive Waterjet (AWJ) at different conditions, and the effect of main process parameters on the characteristics of these surfaces. This analysis revealed that all surfaces have a homogeneous roughness in the transversal and the longitudinal directions, present embedded abrasive particles and have hardened about 50% with respect to the untreated bulk Alloy 718. On the other hand, Plain Waterjet (PWJ) technology was used for removing the abrasive particles embedded in surfaces of Alloy 718 milled previously by AWJ technology. The effect of this process on the surface characteristics is also analyzed. For all tested conditions, this technology removed all the particles embedded in the surface. In addition, the PWJ technology process in general smoothened the surfaces produced by AWJ milling and it also released nearsurface stress. Finally, fatigue tests revealed lower performance of the treated specimens in comparison to untreated specimens, due to crack-like surface irregularities introduced by the treatments.

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Olive oil production is well distributed among the Mediterranean countries. Different levels of processing technology and different industrial organizations co-exist. The production cycle is seasonal and usually concentrated in the fall-early winter period. The pollution characteristics of this industry are peculiar because the flow rates are relatively small while the pollutant load is extremely high and difficult to abate because of the inherent characteristics of low pH and high concentrations of suspended matter, organic matter and lack of nutrients. The free disposal of such waste waters into the environment, though fairly common practice, has disastrous effects on the soil, on aquatic bodies, sewers and on urban waste water treatment plants. Factory specific pre-treatment is too complex and expensive to be realistically adoptable. A territory integrated solution strategy is therefore preferable and a few treatment schemes have here been presented. The recovery and exploitation of the by-products can be justifiable while a realistic consideration of the local realities must be kept in mind. Research is still required to improve and optimize some phases of treatment.

Many electrochemical processes for watewater treatment have been developed over the years. In the field of sewage purification attention has focused on clarification, disinfection and phosphate removal with the aim of reducing costs compared to traditional processes. The on-site production of necessary chemicals is a step towards reducing operating costs. Electrochemical treatment is very efficient and reduces process detention times thereby allowing smaller plants. Sea water or brine is mixed with the screened sewage in an appropriate ratio, then passed through an electrolysis cell rather similar to that used for hypochlorite production. Depending on the material of the electrodes, their arrangement (vertical or horizontal) and the applied potential difference, the reactions which occur produce the chemicals required for the purification processes. Downstream the electrolysis, the mixture flows into a clarification basin which acts as a contact tank for disinfection. The detention time of this process depends on the type of basin used. I report results of electrochemical treatment performed on a semiindustrial scale, using horizontal electrodes: anode of graphite or silicon-iron and stretch-iron cathodes; followed by a sludge recirculation clarification basin. The removal of suspended solids and the abatement of B.O.D. and phosphates were much better than those reached by traditional physical-chemical treatment. The energy consumption is approximately 0.5 kWh/m of raw sewage.