The pollution effect on the denitrifying capacity of methanogenic sludges

Abstract

Denitrification process has been studied for biodegradation of some emerging contaminants (ECs). For this, anaerobic sludges from different Wastewater Treatment Plants (WTP) have been used; however, the biodegradation capacity can differ due to the contact they have had with various pollutants, given their origin. This work aims to evaluate the kinetic and metabolic capacity of two denitrifying sludges from different WTP to biodegrade CH3COO−-C and NO3−-N. Denitrifying tests were carried out in batches with CH3COO−-C (30 mg L−1) in a CN−1 relationship of 1.8 with sludge from a WTP of an educational center (WTP-A) and CH3COO−-C (50 mg L−1) to a CN−1 of 1.4 with another from the WTP of Atotonilco de Tula, Hidalgo, México (WTP-B). The results showed that the biodegradation rate of CH3COO−-C and NO3−-N with the WTP-B sludge was 35 and 75% greater, respectively, compared to the WTP-A sludge. Therefore, we suggest that the consumption difference of substrate is attributable to the sludges of WTP, which have been exposed to a high concentration of a great variety of pollutants.