Monitoreo de la remoción biológica de nitrógeno en efluentes de tenerías usando un reactor por carga secuencial

Abstract

The objective of this research was to relate the biological nitrogen removal in tannery wastewater with profiles of pH, alkalinity and redox potential (ORP) using a sequencing batch reactor (SBR) with a working volume of 2L. The reactor worked under two operational sequences: anoxic-aerobic-anoxic (Ax/Ae/Ax) and aerobic-anoxic (Ae/Ax), which were combined with two cell retention times (CRT) (15 and 25 days), with an operation cycle time (OCT) of 11 hours. The profiles were performed by measuring each 15 minutes the following parameters: pH, dissolved oxygen (DO), ORP, and each hour the parameters: total alkalinity, total chemical oxygen demand (DQOT), soluble chemical oxygen demand (DQOS), total Kjeldahl nitrogen (TKN), nitrite (NO2−), nitrate (NO3−) and ammonia nitrogen (N-NH4+). Alkalinity and ORP profile were excellent indicators of the processes of biological nitrogen removal. However, pH could not be used as a control parameter, due to the buffering capacity of tannery wastewater. Finally, this research work showed that alkalinity and ORP values can be used as on-line control parameters to monitor the evolution of the nitrogen removal in tannery wastewater (nitrification and denitrification processes).