Design and validation of a nitrification and denitrification scheme for wastewater treatment. A case study in the Dominican Republic

Abstract

Wastewater treatment requires systems that provide the guarantee that the treated water has adequate characteristics to avoid pollution. The objective of this research is to design and validate a scheme that contemplates nitrification and denitrification for wastewater treatment in the Dominican Republic. The designed scheme was implemented as follows: a 90-minute cycle, corresponding to 60 minutes in the nitrification process and 30 minutes in denitrification. During this cycle, the concentration of oxygen, ammonium and nitrate was allowed to fluctuate and the concentration of suspended solids was limited in the range of 8,500 to 18,000 mg/l (Table no 1). The scheme described was monitored and controlled in a continuous, automated manner, via the SCADA system. The scheme was subjected to experimentation for three months, with analyses carried out every week. The results have shown that the scheme designed is adequate to provide water with the quality characteristics required by Dominican standards for water leaving the treatment plants (effluent). In this sense, all the parameters analyzed in the influential of the PTAR Rafey have improved the quality of its polluting load at the outlet of the treated water (effluent), always being located below the permissible values in the Dominican standards. In future research, it should be analyzed whether the wastewater treatment scheme proposed by this research improves the nutritional characteristics of the sewage sludge that is generated in the process.