Study on Re-using Media from Iron and Manganese Biological Removal Filter for Defluoridation

The filter media from iron and manganese biological removal filter which w- as replaced by new termly can be re-used. The sand filter media was characterized u- sing the SEM and owns developed interspaces. Drying the sand filter media at 110 degrees C, then inspect and analyse its character and mode of defluoridation. The results show as follows. Under the test condition,the adsorption balance can come out in about 3 hou-rs, the fluoride sorption on the re-used matured filter media followed pseudo-second kinetics. The effect of defluoridation by the matured filter media will be better within the range of pH 3 similar to 7, and best at about pH 4.58. The primary mode of fluoride sorpti- on is chemism, but physical sorption is also in existence, and the adsorption isother- ms could be described by Langmuir equation. Contact-time is a vary important factor in the continuous-flow column experiment. The effect of fluoride removal is long, as the height of filter column is controlled as 40cm. The filter media from iron and manga- nese biological removal filter possess potential of perfect sorbent, space for deeply study and foreground of practical application.