Water shortage and pollution in China have led to the development of wastewater reclamation and reuse methods. Different treatment processes, like pond-farmland systems and activated sludge processes, are used to treat wastewater for irrigation and other non-drinking purposes. Full-scale projects have been implemented in water shortage cities, where treated wastewater is reused in agriculture, industry, and homes. In some cities, a dual water system is used for buildings or residential areas, with treatment involving biofilm processes, filtration, and disinfection.