Polystyrene is a polymer commonly used in civil engineering as styrofoam for building isolation. It is also used in the packaging of glass and sensitive products such as electronics, household products, and other goods. Single-use products such as cups and plates made from synthetic materials are important for waste management. All of these products are responsible for the creation of 6200 kt of waste in 2015 alone. Quite a new idea of the application of styrofoam waste is to use it as basic material for preparation of membranes, which are widely used for water reclamation. Nowadays, membranes are prepared from different, non-waste polymers like polysulfone, poly(ether sulfone), polyacrylonitrile, and others. The aim of this study was to prepare polystyrene waste ultrafiltration membrane and assess its usage to treat river surface water. Conducted tests have been divided into two stages: the first part tested four membranes with different concentrations of waste polymer in order to determine the membrane with the most favorable properties. In the second part, selected membrane was modified with single-walled carbon nanotubes functionalized with hydroxyl groups in three different concentrations. The ultrafiltration process was conducted in a dead-end system under pressure of 0.1 MPa. The obtained results suggest that the ultrafiltration membranes with waste styrofoam guarantee similar treatment effects as with the usage of membranes made with other polymers or commercial membranes.