Environmental and Economic Impacts of Different Disposal Options for Ulva prolifera Green Tide in the Yellow Sea, China

The Ulva prolifera ( U. prolifera ) green tide has had a large-scale eruption in the Yellow Sea of China for 15 consecutive years. A large amount of coastal U. prolifera has been salvaged and brought ashore for further disposal, but little is known about the environmental impact of its disposal. Using Qingdao as a representative, this study quantifies the life cycle environmental impact and cost of disposal options to deal with the outbreak of the Yellow Sea U. prolifera in China, including incineration, fast decomposition, stabilization, and recycling. In addition, we also analyzed two potential disposal options (anaerobic digestion to produce biogas and fermentative distillation to produce ethanol). In 2021, Qingdao spent 350 million CNY and consumed 46.7 kt oil-Eq of fossil fuels and emitted 331.0 kt CO 2 -Eq of greenhouse gases in response to the eruption of the U. prolifera green tide. Scenario analysis shows that comprehensive utilization is a crucial step to maximize the environmental and economic benefits of U. prolifera disposal, including recycling for fertilizer production and anaerobic digestion for power generation. The combination of source control and comprehensive utilization will minimize the impact of the Yellow Sea U. prolifera green tide.