Although the appropriate supply of nutrients has been extensively researched, more information is required on the effects of nutrients in treating gaseous volatile organic compounds (VOCs) in biofiltration. In this study, the effects of phosphorous and trace metals on gaseous toluene and methyl ethyl ketone (MEK) removal were investigated. The transfer of nutrients from the irrigation liquid to the packed bed, and the consumption and holding amount of nutrients in the packing material were observed during biofiltration. Under conditions of 20-24 s of empty bed residence time, MEK removal was 95% or more in all conditions of the biofiltration reactors, whereas toluene removal was affected by the operating conditions of the reactors. Consumption ratio of phosphorus to carbon was from 1.7 × 10 −4 to 1.1 × 10 −3 in the steady state of VOC removal under the conditions of this study. When gaseous VOC treatment was restarted after nine days of shutdown, a significant decline in toluene removal was observed by the reactor in which phosphorus supply was approximately one fifth of the amount in another reactor. Two types of irrigation systems, soaking and spraying, were compared and soaking irrigation achieved a more even distribution of nutrients held inside the packed bed. Soaking irrigation was expected to lead to higher VOC removal capacity by this distribution effect of nutrients, but toluene removal in the reactor with this irrigation was lower than that in the reactor with spraying irrigation. One of the possible reasons for this was the inhibition of nutrients transfer in the bottom part of the reactor. The trend of transfer in all ingredients from the irrigation liquid to the packed bed was synchronized on the whole; however, this transfer relatively tended to be high in nitrate and sodium and low in ammonium and phosphate.Implications: A major concern about using biofiltration systems to treat VOCs is the uncertainty regarding the appropriate nutrient supply to the filter bed to preserve microbial activity. This study showed that all the elements, except nitrogen, were retained sufficiently in the filter bed when a proper composition of nutrient solution was used for irrigation; however, phosphate addition may be needed when restarting a reactor from a prolonged period of shutdown. Distinct differences in the amount of transfer to the filter bed for different ingredients are probable, and may have to be taken into account when operating biofiltration reactors.
Sixteen neonates were born from epileptic women under anticonvulsant treatment. Most of the mothers were administered phenobarbital and phenytoin. Although no congenital anomaly was observed, 2 neonates showed hemorrhage and one died 25 hours after birth from profuse intra‐abdominal hemorrhage derived from ruptured subcapsular hematoma of the liver.
The cord blood concentration of anticonvulsants correlated well with both maternal daily dose and maternal blood concentration. The ratio of cord blood to maternal blood concentration was approximately 1: 1 with phenobarbital and phenytoin. In the 2 neonates with hemorrhage, both the maternal dose and the cord blood concentration were relatively low.
The cord blood of neonates born from an epileptic mother treated with anticonvulsants (especially phenobarbital and phenytoin), should immediately be submitted to coagulation tests, even if maternal daily dose or blood concentration of the drug is low. Such infants should be closely observed and be transfused with fresh frozen plasma, if bleeding is detected.
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