A recycling system that’s capable of simulating a free flowing fire hose — without wasting water — will be the main feature of a Riverside Fire Department drill Tuesday attended by the mayor, fire chief and other officials. The agency’s new “PumpPod” will be unveiled during a demonstration exercise scheduled for Tuesday morning at the city’s Emergency Operations Center on Saint Lawrence Street. The recirculation system was acquired by the fire department thanks to a $3 million California Department of Water Resources grant administered by the Metropolitan Water District of Southern California.