A moving-boundary model of reactive settling in wastewater treatment. Part 1: Governing equations

Reactive settling is the process of sedimentation small solid particles in a fluid with simultaneous reactions between components and liquid phases. This important sequencing batch reactors (SBRs) wastewater treatment plants. In that application are biomass (bacteria; activated sludge) contains substrates (nitrogen, phosphorus) to be removed through biomass. The operation an SBR cycles consecutive fill, react, settle, draw, idle stages modelled by system spatially one-dimensional, nonlinear, strongly degenerate parabolic convection-diffusion-reaction equations. coupled via conditions mass conservation transport equations on half line, whose origin located at moving boundary model effluent pipe. An invariant-region-preserving finite difference scheme used simulate operating denitrification within SBR.