providing an influent flow to a set of modules stacked on top of each other, each module including screen assemblies and filter media sandwiched between the screen assemblies;

filtering the influent by directing the influent through fluid lines and control assemblies operable for selectively communicating flow to individual modules;

selectively bypassing a forward flow from a module being bypassed around a subsequent module when the module becomes occluded, the forward flow being reintroduced from a previous module to a subsequent module; and

backwashing the occluded module by providing a reverse flow through the screen assemblies and the filter media while bypassing the forward flow around the occluded module.