Historic Trends and Future Prospects of Waste Generation and Recycling in China's Phosphorus Cycle

Intensified human activities have generated a large amount of phosphorus-containing waste (P waste). Unrecycled P waste is lost to the environment and causes eutrophication, while the increasing phosphate consumption risks the depletion of phosphorus resources. The management of P waste is critical to solving these problems. In this study, we quantified the historic trends of P waste generation and recycling in China. From 1900 to 2015, the annual generation of P waste increased from 1 Mt P to 12 Mt P. Crop farming was the largest P waste source in most years, while P waste from phosphate mining and phosphorus chemical production increased the fastest. The total recycled P waste increased 5-fold, but phosphorus loss increased 26-fold. In 2015, 28% of the P waste was lost on cultivated land, and 21% was lost on nonarable land. The largest phosphorus contributor to inland water changed from crop farming to aquaculture. The full recycling of P waste would have reduced phosphate consumption by more than one-third in 2015. The results of a scenario analysis showed that a healthier diet would greatly increase the generation and loss of P waste, but balanced fertilization could reduce the generation of P waste by 17% and promoting waste recycling could reduce the phosphorus loss by 35%.