Biological denitrification of underground brackish water using methanol and sugar cane as a carbon source

Abstract

The nitrate content in many parts of Morocco exceeds acceptable standards, especially in agricultural regions like the Gharb region (M′nasra). In this region, the nitrate content exceeds 400 ppm in some wells. Nitrate contamination is attributed to overuse of fertilizers. In Morocco, the maximum acceptable concentration of nitrate in drinking water is 50 mg/L. In this study, two natural organic substrates methanol and sugar cane, were investigated as a potential carbon source in the biological denitrification of drinking water. The experiments were carried out in batch process. Complete denitrification was practically achieved with both methane and sugar cane in the same experimental conditions. Results showed that the sugar cane could be used as an alternative carbon source for denitrification with complex process control and continuous monitoring. It should be noted that sugar cane needs to be changed periodically for the continuation of the process. Therefore, the removal efficiency of methanol varied between 78 % and 98 % according to the conditions of presence or absence of deoxygenation. For sugar cane, it was found that the nitrate removal rate was up to 98 % without deoxygenation.