RESUMO
This study evaluates Alum sludge from drinking water treatment plants for the efficient and cost-effective removal of phosphates from aqueous solutions. Extensive characterization and batch experiments have established that optimal phosphate removal was achieved with a sludge dosage of 20 g L-1 (at an initial phosphate concentration of 100 mg L-1), a pH of 5, a temperature of 23 °C, and a stirring speed of 200 rpm. These conditions significantly reduced phosphate levels, ensuring compliance with legal discharge limits. The Langmuir isotherm, pseudo-second-order kinetic and intraparticle diffusion models best described the adsorption process, highlighting the spontaneous and endothermic nature of the phenomenon. The sludge effectively reduced phosphate concentrations to acceptable levels when applied to dairy effluents. This study underscores the potential of Alum sludge as a viable solution for phosphate management in environmental cleanup efforts.
Assuntos
Compostos de Alúmen , Indústria de Laticínios , Fosfatos , Esgotos , Adsorção , Fosfatos/química , Esgotos/química , Compostos de Alúmen/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química , Purificação da Água/métodos , Cinética , Modelos QuímicosRESUMO
A series of food poisoning outbreaks, due to the consumption of imported non-fat dried milk (NDM), occurred in Egypt during 1986. Bacteriological examination was carried out on two samples of the remaining NDM for the outbreaks, and 90 samples of the imported NDM, represented nine code numbers. All of the samples tested were free of coagulase positive staphylococci, Salmonella , Shigella , Bacillus cereus , Clostridium perfringens , and Escherichia coli , and the viable bacterial counts ranged from 7.9 × 102 to 5.0 × 104 cells/g. However, staphylococcal enterotoxins B & A (1.5 & 0.125 µg/100 samples, respectively) were detected in the NDM samples remaining from the outbreaks. At the same time, out of 27 representative samples of NDM, three samples, with the same code number, contained staphylococcal enterotoxin B (1.25 µg/100 g), and one of those three samples contained staphylococcal enterotoxin A (0.125 µg/100 g).