BACKGROUND: The discharge of food waste and eutrophication in aquaculture could cause environmental pollution and ecological disasters in the hydrosphere. Herein, a novel model of growing microalgae to recover nutrients from food waste and produce feed substitute for aquaculture is proposed. RESULTS: This study developed different methods to pretreat soybean fermentation effluent (SFE) and assessed the contribution of algal growth to nutrient recovery from SFE. Particularly, change of bacterial community was analyzed to explore the interaction between microalgae and bacteria in SFE remediation. In addition, the inclusion level of microalgae in fish diet was optimized and the effect of fresh microalgae on the aquaculture environment was studied. The results showed that unsterilized SFE with appropriate dilution is favorable for microalgal growth and biomass accumulation. Interaction between microalgae and acidogenic bacteria, including Prevotella sp., Acidaminococcus sp. and Lactobacillus sp., favored nutrient recovery from SFE. Removal efficiency of chemical oxygen demand, total nitrogen, total phosphorus and total ammonia‐nitrogen in SFE reached 95.66%, 35.35%, 57.70% and 42.21%, respectively. As the optimal inclusion level of microalgae in fish diet was set as 25%, body length and weight of Micropterus salmoides increased by 13.85 mm and 1.73 g in 44‐day culture. It was also found that fresh microalgae added in fish diet could effectively keep the ammonia concentration in aquaculture system at a lower level. CONCLUSION: The implementation of this model will be of importance to circular economies integrating food waste remediation and eco‐friendly aquaculture. © 2021 Society of Chemical Industry (SCI).

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Waste electrical and electronic equipment (WEEE), also called electronic waste or e-waste, the core of “urban mining”, is attracting more and more attention to its pollution control and circular recycling. Hence, we defined WEEE, preliminarily discussed its history in China and pointed out that China has made great achievements in WEEE circular reutilization and pollution control. Meanwhile, we analyzed the four levels of circular WEEE recycling: repair, reuse and remanufacture, waste-to-materials, waste-to-products and waste-to-energy, and also put forward questions during this process. Moving forward, WEEE management will turn to intelligent management targeted on hazardous waste and other pollution, not merely the guidelines. Meanwhile, WEEE technology will transfer to value-added and automated reutilization, not just simple dismantling.

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