The water supply in most cities of our country is strictly treated at the water treatment plant, and various water quality indicators meet the national sanitary standards for drinking water; however, during the process of being transported to users through long-distance water supply pipelines, complex physical, chemical, and biological changes occur, leading to secondary pollution of drinking water quality. For example, outdated water supply pipes, corrosion and scaling on the inner walls, and microbial films on the pipe walls can cause an increase in turbidity, color, total bacterial count, iron, manganese, and other contents in the water. China's water purification market has a large capacity and strong rigid demand, with good development prospects. In research, it is necessary to adopt scientific water treatment technologies according to different water quality characteristics to ensure high-quality drinking water. This study combines granular activated carbon, ultrafiltration membranes, and ultraviolet disinfection processes, where each treatment unit complements the others, achieving average removal rates of 89.8% for turbidity, CODMn, UV254, and total bacteria count, respectively. 90.7%, 96.2%, and 99.5% ensure the good purification of tap water quality, with the effluent water quality exceeding the national 'Drinking Water Quality Standard' (CJ94-2005), providing people with safe and reliable direct drinking water in real time. Additionally, a second generation direct drinking water device has been developed and successfully applied to the direct drinking water project within the Expo Park at the 2010 World Expo.