Galvanization process requires the use a large amount of water and produces wastewaters that are usually purified by conventional cost-effective procedure. This kind of treatment generates waste sludge which becomes a hazardous if is not properly stabilized. Hence, the aim of this paper is to investigate the characteristics of galvanic sludge through the inspection of its physicochemical parameters and consider stabilization of waste materials, including waste glass and aluminum slag by their conversion into an eco-designed material referred to as glass ceramics. The obtained products have been studied by X-ray diffraction (XRD). XRD analyses confirmed occurrence of chemical and phase transformations in treated galvanic sludge and binding of toxic metals (Al 3+ , Cr 3+ , Cu 2+ , Cd 2+ , Ni 2+ , Pb 2+ , Zn 2+ ) into crystalline phases and very sTab. structure.

The effects of the coagulation/floculation conditions on clarification and filtration of the floculated particle suspension obtained by the chemical treatment of the waste oil-in-water emulsion (OWE) from a non-ferrous metalworking plant were studied. The treatment involved the addition of aluminum(III) sulfate and lime to the OWE. The main goal was to define the optimum conditions for clarification and filtration of the floculated particle suspension. The factors involved were amounts lime (i.e. pH) and filter aid added the OWE on clarification and filtration rates. At pH>10, the clarification rate was increased and the final volume of the concentrated suspension (sludge) was reduced, while filter aid affected negatively the clarification rate. The filtration rate was also increased when the coagulation was carried out at pH>10. The floculated particle suspension should be concentrated before filtration in order to decrease the filtration duration. The most efficient filter aid was Celite standard super-cel, its optimum initial concentration being found to be 2 g/dm3

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Used water emulsions obtained in the metalworking process contain oils and grease, organic compounds as well as secondary oils and anti-corrosion fluids, metal ions and other things. Since they can have a negative effect on the environment before released into the recipients, they need to be processed through the primary, secondary and tertiary phase of treatment. The primary treatment procedure of waste oil-in-water emulsions is used for the separation of free and non-emulsifying oils as well as for balancing the course of wastewater and oil concentration. In the secondary phase of treatment of waste oil-in-water emulsions, the emulsifying oil and a large fraction of dissolved oil are carried out. What follows is the tertiary biological treatment based on the basic biological processes present in nature. Key words: metalworking, waste oil-in-water emulsions, treatment

The technology of meat processing involves the processes and operations which lead to the emission of harmful gases, wastewaters and sludge. In order to monitor more easily and to remove the possible causes, this paper analyses the critical points of the technology of meat processing as well as the consequences of undesired events, aiming at reducing the risk level. Key words: meat industry, wastewater, critical control points