Biologisk denitrifikation av dricksvatten - Biological denitrification of drinking water

• A pilot-plant study, made to clarify whether biological denitrification is a possible and suitable method for nitrate reduction of drinking water in Sweden is presented. The concentration of nitrate-nitrogen in un-treated water was 10–15 mg/l. The reactor was a 1.2 m aluminium tube with a inner diameter of 0.19 m. 0.75 m was filled with Filtralite®, expanded clay, through which the nitrate-contaminated water was forced to flow upwards with a velocity of 0.5 m/h. The system was run with artificial nitrate-polluted potable water from the three pumps during a week. The nitrate was then added to the water by using a solution of sodium nitrate. As carbon-source, sodium acetate was used. The Hydraulic Retention Time (HRT) of the system was 5.9 h, of which approximately 2.6 hours were within the bacterial support material. The C:N ratio was found to be below 1.5 and the system was very stable. Since the process will not work as long as oxygen is present, oxygen was degassed, but the importance of trace oxygen amounts could not be decided, since it wasn’t possible to decrease the oxygen to really low concentrations in the water prior inlet to the reactor. It was concluded that it is possible to use biological denitrification for drinking water. Post-treatment in an aerated reactor will be needed to ensure that no carbon or nitrite-nitrogen comes into the potable water.

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Kemiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Chemical Engineering (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Samhällsbyggnadsteknik -- Vattenteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Civil Engineering -- Water Engineering (hsv//eng)

Publication and Content Type

art (subject category)

vet (subject category)