In situ batch denitrification of nitrate rich groundwater using sawdust as a carbon source - Marydale, South Africa

Abstract

Batch experiments were performed to denitrify groundwater using sawdust as a carbon source at Marydale, South Africa. Alkalinity, pH, Electrical Conductivity, nitrate, nitrite, ammonia, SO42-, heterotrophic plate count (HPC), dissolved organic carbon (DOC), potassium and chloride was monitored. Two soil depths, 75 to 100cm and 165 to 200cm respectively, from the Marydale area were used as matrix material during denitrification based on contrasting chemical composition with respect to major ion composition and moisture to consider different denitrification rates for varying soil depths. Different N: C ratios were used to evaluate the denitrification efficiency and the least undesirable products e.g. elevated SO42-, H2S and other reduced compounds. DOC is directly proportional to the N: C ratio used. Nitrite was produced for most of the treatments as incomplete denitrification occurred