Modelling a spatially heterogeneous biofilm and the bulk fluid: selected results from Benchmark Problem 2 (BM2). - Eberl, H. J.; Van Loosdrecht, M. C. M.; Morgenroth, E.; Noguera, D. R.; Perez, J.; Picioreanu, C.; Rittmann, B. E.; Schwarz, A. O.; Wanner, O. (Water Science & Technology, 2004)