Drinking Water, Biological Denitrification of Groundwater

Denitrification of groundwater for drinking water production has become more and more important in the recent time, due to the increasing nitrate concentration in aquifers. In this context, biological denitrification has become a popular means of controlling this contamination. This method is based on the conversion of nitrate to nitrogen gas by bacteria under low-oxygen conditions, resulting in a complete elimination of nitrate and not just its separation. Its good results and benefits make it an ideal technology to remove nitrate from groundwater sources. Although the principle behind the technology is simple, its application can be complicated because parameters such as carbon substrate, temperature, and pH influence its effectiveness. The most commonly used carbon sources are methanol, ethanol, and acetic acid. The right choice depends on plant specifications, economic factors, and general access to the substrate. On the other side, temperature can affect the well-being of bacteria and thus affect denitrification. Low temperatures decrease the denitrification performance considerably. In comparison, the pH value of the groundwater is in most cases already in the slightly basic range and thus in the optimum, so that no adjustments are necessary.