Anaerobic SBR - Aerobic SBR coupled system. Analysis and simulation.

FUENTES, M; AGUIRRE, P; SCENNA.

PROCESS SAFETY AND ENVIRONMENTAL PROTECTION

INST CHEMICAL ENGINEERS

Año: 2013

0957-5820

The operation of granulated coupled anaerobic SBR ? aerobic SBR for wastewater treatment is addressed. These systems are of increasing interest for organic carbon as well as biological nitrogen loads reduction in small scale wastewater facilities. For design and operations purposes each operation step in each reactor could be considered as time dependent from the other reactor operation. The different steps in each reactor should be designed in order to obtain feasible operations. Furthermore, recycling streams from the aerobic reactor must be obtained and recycled to the anaerobic SBR reactor in order to obtain de-nitrification. At the same time, part of the influent stream should by pass the anaerobic reactor in order to provide Carbon source to the aerobic reactor. In early simulations as well as in experimental studies nitrite inhibition is observed in the aerobic SBR operation. Hence, nitrite inhibition is included into the aerobic kinetic model. Experimental values are well predicted with this model modification. The main variables of the whole process are analyzed and different operation strategies are presented. The results show that the recycle and bypass fractions used in the actual design can be recalculated keeping an adequate C:N ratio for digestion processes and guarantying the quality of treated effluent. In addition, the model allows to study the flexibility of the system in from of eventually changes in the design variables such as the batch size and cycle time without affecting the production rate.