The circular economy requires advanced methods to recycle waste matter such as ammonia, which can be further used as a fuel and a precursor of numerous value-added chemicals. Here, we review methods for the recovery of ammonia from wastewater with emphasis on biological and physicochemical techniques, and their applications. Biological techniques involve nitrification, denitrification, and anammox processes and the use of membrane bioreactors. Physicochemical techniques comprise adsorption, membrane filtration, ion exchange, chemical precipitation, ammonia stripping, electrochemical oxidation, photocatalytic oxidation, bioelectrochemical systems, and membrane hybrid systems. We found that nitrification and anammox processes in membrane bioreactors stand out for their cost-effectiveness, reduced sludge production, and energy efficiency. The use of struvite precipitation is an efficient, environmentally friendly, and recyclable method for ammonia removal. Membrane hybrid systems are promising for ammonia recovery, nutrient concentration, and wastewater treatment, with applications in fertilizer production and water purification. Overall, nitrogen removal ranges from 28 to 100%, and nitrogen recovery ranges from 9 to 100%.

循环经济需要先进的方法来回收氨等废物，这些废物可以进一步用作燃料和许多增值化学品的前体。在这里，我们回顾了从废水中回收氨的方法，重点是生物和物理化学技术及其应用。生物技术涉及硝化、反硝化和厌氧氨氧化过程以及膜生物反应器的使用。物理化学技术包括吸附、膜过滤、离子交换、化学沉淀、氨汽提、电化学氧化、光催化氧化、生物电化学系统和膜混合系统。我们发现膜生物反应器中的硝化和厌氧氨氧化过程因其成本效益、减少污泥产量和能源效率而脱颖而出。使用鸟粪石沉淀是一种高效、环保、可回收的氨去除方法。膜混合系统在氨回收、营养物浓缩和废水处理方面具有广阔的前景，并可应用于肥料生产和水净化。总体而言，氮去除率范围为 28% 至 100%，氮回收率范围为 9% 至 100%。