RESUMO
Elemental chlorine-free (ECF) bleach effluents from kraft mill are characterised by: a chemical organic demand/biological organic demand (COD/BOD(5)) ratio of 4, chlorophenol content with low chlorine substitution, and toxicity. The effect of increasing the concentration of 2,4,6-trichlorophenol (2,4,6-TCP) content in ECF bleaching sequence effluent on the degradative activity of bacterial communities present in an aerobic system treatment was studied. An aerobic lagoon (AL) was used as a typical secondary treatment of kraft-mill effluent. AL displays a high performance of BOD(5) degradation (up to 90%); however, only 40% of the COD was removed. Simultaneously, the AL system shows a high ability to biodegrade 2,4,6-TCP up to 237 mg/l day. Kinetic parameters of the 2,4,6-TCP biodegradation by aerobic bacteria were determined. The K(s) and K(i) values were 34.3 and 50 mg/l 2,4,6-TCP, respectively. Moreover, the tolerance of aerobic bacteria was observed up to 1.3 g/l 2,4,6-TCP.
Assuntos
Clorofenóis/metabolismo , Mutagênicos/metabolismo , Bactérias Aeróbias , Biodegradação Ambiental , Resíduos Industriais , Cinética , Papel , Purificação da ÁguaRESUMO
The cesarean section is associated with a high incidence of puerperal infections. The antibiotic prophylaxis in obstetric surgery may reduce infectious complications, nevertheless antibiotic prophylaxis only has proved to be effective in women with risk factors for the occurrence of infection. We made a comparative study of the prophylactic efficacy of the ceftriaxone a single dose versus cefazolin three doses, in women with risk factor for infection. There were enrolled 100 patients, 50 in each group. Six percent of the ceftriaxone group patients developed puerperal infections while 12% of the cefazolin group women developed this complication. The statistic analysis don't show difference between the groups. We consider the single dose prophylactic schema is better because its application is easier, administration is safety and reduces the risk of adverse reactions.