Revealing factors influencing spatial variation in the quantity and quality of rural domestic sewage discharge across China

Understanding the characteristics of domestic sewage discharge in different rural areas is an important prerequisite for effective sewage treatment . Here, we revealed the spatial variation in the water quantity and quality of rural domestic sewage and its influencing factors in 31 provinces and cities of China, based on a multi-factorial analysis. The results showed that the water quantity of rural domestic sewage discharge generally increased from Northwest to Southeast in China and the water quality had opposite pattern. The water quantity was positively correlated with water resources, gross domestic product, rainfall, and temperature, but negatively correlated with altitude. Water resources, with an influence weight of 25.04% by principal component analysis, had the greatest impact on the spatial variation in water quantity. Differently, gross domestic product, which was directly negatively correlated with ammonium-nitrogen and total phosphorus in structural equation model, was a dominant factor influencing water quality. These findings will help us to better understand the factors of controlling rural domestic sewage discharge at a national scale and to optimize the treatment technology of rural domestic sewage.