A membrane filtration unit is operating with 72.5 m2 of membrane and processes 130 L/min feed of wastewater. The permeate flow is 85.4 L/min. The filter removes suspended solids from a waste stream such that the concentration in the permeate is 28.9 mg/L compared to 3,992 mg/L in the retentate. Determine the flow of retentate (in L/min). Report answer to one decimal place.