Articles

Foaming problems are wide-spread, being reported by many wastewater treatment plants around the world, and consist in: reducing effluent quality caused by sludge loss, recirculation difficulties, diminution of oxygen transfer inhibiting nitrification, difficulty in maintaining the appropriate sludge concentration in the aeration vessel. In order to demonstrate foaming causes, a complete characterization of wastewater samples taken from the treatment plant of the Coke-Chemical Factory in Galati was made. The sampling points were chosen in the most important parts of the wastewater treatment plant: ammonia striping input/output, output from 2nd step of biological wastewater treatment. In order to select the appropriate means for foaming elimination/diminution, six antifoaming agents acquired from Degusa-Hüls (Stockhausen) and IFIN – Bucharest were tested. The most efficient antifoaming agents were found to be those from Stockhausen, considering the efficiency decreasing: BA, WA, ZU. The treatment with antifoaming agents leads to the total elimination of foam, while the duration of antifoaming effect depends on the type of antifoaming agent. The applied antifoaming dose was 20 ppm.

In terms in available natural water resources (surface and groundwater), Romania finds itself within the category of country with a limited potential. Regarding the quality of these resources, the formal statistics reflect their poor quality due to the impact of point emissions and the diffuse emissions, typical for industrial and agricultural activities. It has to be mentioned that the groundwater quality is seriously affected in areas where chemical and petrochemical units are not develop specific activities, especially for individual water consumers (rural households) which are not connected to a centralized drinking water system for treatment. The work presents the compliance evaluation of different water resources versus the applicable legal norms, the investigation being related to rural settlements for different sites in Prahova county (petrochemical industry) and Valcea county (chemical industry). Based on detailed analytical investigations, the following remarks are to be made: the nature and contamination level of organic pollution reflect the influence of petrochemical and chemical plants on the groundwater used as drinking water in surrounding rural settlements; aromatic hydrocarbons (BTEX) and phenolic compounds are present in concentrations over the legal regulations in the groundwater affected by the activity of a petrochemical plant; organohalogenated pesticides (HCH), phenolic compounds and volatile organic compounds (VOCs) were identified in natural resources located in the close proximity of a chemical plant; the associated inorganic pollutants for these natural resources is due to the presence of iron, nitrates, phosphates ions. Based on each specific pollution profile the treatment flows for two locations are elaborated in order to assure the compliance of water quality with the enforced regulations.