Batch studies on nitrate removal from potable water

A sulphur / limestone autotrophic denitrification process was used to achieve the biological removal of nitrate from groundwater. The feasibility of the system was evaluated under anaerobic conditions using laboratory-scale batch reactors. The optimum sulphur / limestone ratio was determined to be 1:1 (wt/wt). Different initial nitrate-nitrogen concentrations (94, 57, and 10 mg NO3--N/l) were used during the batch tests to examine nitrate removal efficiencies. The results showed that the higher the initial concentration, the longer it takes before nitrate removal commences. Both total suspended solid (TSS) and mean size of particles increased with time, which may be related to bacterial growth in the system. WaterSA Vol.28(3) 2002: 319-32