High nitrate levels in drinking water are the primary cause of methemoglobinemia, and evidence points to
a potential linkage between nitrate intake and cancer. The concentration of nitrate in water sources has
steadily risen in developed countries. An attractive alternative to physical and chemical treatment for
removing nitrate is biological denitrification. Autotrophic denitrification is recommended over
heterotrophic denitrification because of downstream instability issues associated with heterotrophic
denitrification. In this research, hydrogenotrophic denitrifiers were used along with a dead-end Hollow
Fiber Membrane Bioreactor (HFMB). The HFMB increased the mass transfer of H2 to improve the
denitrification rates and negate any combustion issues affiliated with H2 gas. Also, the HFMB supported
a high biomass density. The objectives of this project were to compare the denitrification rates and water
quality with previous research, control biofouling, and investigate effects of partial H2 pressure and
mixotrophic metabolism on denitrification rates. The research resulted in denitrification within 24 hours
of startup, along with denitrification rates comparable to previous research. Controlling the biofilm by
shearing with N2 gas improved both the average denitrification rates and effluent turbidity, TOC/DOC,
and heterotrophic plate counts. The mixotrophic metabolism resulted in a slight increase in average
denitrification rate over an autotrophic environment. However, the concerns associated with an organic
carbon source carryover questions the practicality of the mixotrophic concept.
Includes 28 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 400 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 19 |
| Published : | 06/16/2002 |
