This paper discusses the applications of synthetic PONILIT GT-2 anionic polyelectrolyte in conjuction with ferric sulfate in a chemical wastewater treatment viz. wastewater from ceramics manufacturing. Synthetic wastewaters with different colloid concentrations were prepared and the coagulation-flocculation process followed by sedimentation and/or filtration was studied. Variables associated with the chemical wastewater composition, mixing time, and the coagulant and flocculant dose are considered in order to appreciate the process efficiency in terms of turbidity, chemical oxygen demand (COD), and color removal. The degrees are higher for turbidity and color (> 80 %) removal respectively, and, satisfactory for COD (< 50 %). An empirical model was elaborated by a third order rotatable design 2 3 type, considering ferric sulfate dose, polyelectrolyte dose, and mixing time as independent variables, while the turbidity and color removal efficiencies were chosen as optimization criteria. The empirical model was found adequate for the chemical wastewater treatment. Also, an analysis of the model was performed to find the optimal operating conditions, in order to apply this process for an efficient chemical wastewater treatment using ferric sulfate as coagulation agent and PONILIT GT-2 anionic polyelectrolyte as flocculation agent. The optimal values correspond to a ferric ions concentration of 6.093 mg/L, a polyelectrolyte dose of 0.651 mg/L, and a mixing time of 24.024 minutes for turbidity removal (95.869 %), respectively, and, to a ferric ions concentration of 6.01 mg/L, a polyelectrolyte dose of 0.69 mg/L, and a mixing time of 26 minutes for color removal (98.741 %).

This paper discusses the applications of synthetic PONILIT GT-2 anionic polyelectrolyte for chemical wastewater treatment. Synthetic wastewaters with different colloid concentrations were prepared and the flocculation process followed by sedimentation and/or filtration was studied. Variables concerning the chemical wastewater composition, temperature, mixing time, and flocculants dose are considered in order to appreciate the process efficiency (e.g., turbidity, color and organic matter removals). The removal degrees of turbidity and color are important (>80%) and, respectively, acceptable for organic matter expressed by Chemical Oxygen Demand (COD removal <45%). An empirical model was elaborated by a third order rotatable design 2 3 type, considering temperature, polyelectrolyte dose and mixing time as independent variables, while the turbidity and color removal efficiencies were chosen as optimization criteria. The mathematical model was found adequate for the chemical wastewater treatment. Also, an analysis of the model was performed to find the optimal operating conditions, in order to apply this process for efficient chemical wastewater treatment using PONILIT GT-2 anionic polyelectrolyte as flocculation agent.

Some investigations concerning the decolorization of Acid Red G azo dye by photooxidation with hydrogen peroxide were performed. The influences of pH, oxidant concentration, and the presence of Fe 2+ or other metal ions (Co 2+ , Cu 2+ , Ni 2+ , Mn 2+ ) as potential catalysts, were investigated. The best results were obtained in the presence of ferrous ions in acid and neutral media. The other ions are not as effective as Fe 2+ for dye decolorization. Co 2+ and Cu 2+ ions have a catalytic action, at low concentration, within a wide range of pH. Ni 2+ and Mn 2+ ions have no catalytic effect in photooxidation with hydrogen peroxide at acid pH values, but show a weak action in alkaline media.

The applications of electrochemical technologies based on electrocoagulation/ electroflotation for removal of pollutants as oil, organic compounds expressed through Chemical Oxygen Demand (COD), heavy metal ions together with colloidal particles from wastewaters in the presence of a cationic polyelectrolyte (PRODEFLOC CRC 301 commercial product, dose of 0.25 mg/L) are discussed. Experiments were performed into an electrocoagulation/electroflotation cell without diaphragm with monopolar electrodes in order to establish the optimal operational conditions (e.g.: electroflotation/ electrocoagulation time, electric current intensity or electricity quantity) for removal efficiencies of more than 60 % COD, 95 % oil, 80 % turbidity and 85 % zinc ions. This treatment can be applied instead of conventional mechanical-chemical techniques that lead sometimes to irregular average removal degrees of all important pollutants.

The investigated site is a heat and power co-generation plant situated into an industrial area, having a total surface of 18.38 ha. The most important facilities of this plant are energetically and industrial stream generation, electricity generation, hot water generation, electric energy transmission system to National Energetic System, and liquid or/and gaseous combustion fuels units. The environmental impact is assessed using the method of global pollution index, as was proposed by Rojanschi and improved by Popa et al., in order to get the final results in a very useful way. The studied environmental components are considered: air, surface water and soil. For each components is established an evaluation degree and calculated the global pollution index. The results of the two studied global pollution methods applied for an energetically unit are similar, and correspond to the situation of "environment modified by industrial/economic activities dangerous to life form". The activity of the heat and power co-generation plant seriously modifies the environmental quality, especially air quality, inducing a great impact in environment. This requires remediation actions and pollution control for minimization of all emissions into environment.