Computational uncertainty quantification for a clarifier-thickener model with several random perturbations: A hybrid stochastic Galerkin approach. COMPUTERS & CHEMICAL ENGINEERING, (89):11-26, PERGAMON-ELSEVIER SCIENCE LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND, June 2016. [PUMA: Finite Galerkin Galerkin; Hybrid Polynomial Uncertainty chaos; method} model; projection; quantification; stochastic volume {Clarifier-thickener]