Assessment on the performance of a series of two UASB reactors compared against one of the same total volume using Anaerobic Digestion Model No 1 (ADM1).

The ADM1 is applied to simulate the behaviour of an Upflow Anaerobic Sludge Blanket Reactor (UASB) treating blood powder (spray dried blood meal) wastewater. Considering a completely mixed liquid phase, the model is defined by a set of differential equations which can be numerically solved. Experimental data allows validating the output of the model which is then used for performing numerous simulations. A single reactor is compared to a series of two identical reactors of half the volume each. For the same total hydraulic retention time, the series reaches an outlet concentration 74% inferior to that of the single reactor. Furthermore, for the same total conversion the volume required by the series is 43% of that of the single reactor.