Gross-Wen Technologies of Ames received the top prize of $25,000 Thursday in the 2017 Pappajohn Iowa Entrepreneurial Venture Competition, Clay & Milk magazine reported. The winners were announced during a luncheon hosted at Drake University. Gross-Wen, which is participating in the ISU Startup Factory, is commercializing an algal wastewater treatment technology that was developed at Iowa State. Lienwaivers.io, a Sioux City company that developed a cloud-based construction payment platform, finished in second place to win $15,000. Vacation rental insurance company Pablow, an insurtech startup based in Des Moines, received the third-place prize of $10,000.