The history and prediction of composting technology: A patent mining

Composting technology (CT) is a bridge between organic waste and soil carbon pool, which also a critical technology on the sustainable development of agriculture. Although some attempts have been made to address the CT assessment, technical details are not yet available; this brought difficulties in predicting the development directions. Here, patent measurement was used to analyse the structured and unstructured scripts of 11,701 composting technology patents (CTPs) in the Derwent Innovations Index database. It was discovered that the history of CT could be divided into the budding stage (1970-1989), the developing stage (1990-2006) and the expanding stage (2007-2019). Environmental policies are highly related to CT development. China authorised the most CTPs, accounting for 43.89% of the world's total. The World Intellectual Property Organization and the European Patent Office made a significant contribution to patent flow. The co-words analysis suggested that the technological aim of CT has shifted from waste disposal to organic fertiliser preparation. Cluster analysis sectored CTPs into 42.76% of which focuses on the composting device. Through the mining results and literature reviews, the subject of using mineral in compost, anaerobic fermentation, new microbial strain, straw composting and preparation of high-efficiency organic fertiliser were the potential research directions. This study investigated the history of CT and predicted possible trajectories that could be informative to eliminate repetitive and subsidiary horizontal innovations. (C) 2020 Elsevier Ltd. All rights reserved.