Luu The Anh, Nguyen Gia Cuong, Truong Manh Tuan, Le Van Giang, Bui Xuan Thanh
Central Institute for Natural Resources and Environmental Studies, Vietnam National University Hanoi 111000 Vietnam
Key Laboratory of Advanced Waste Treatment Technology, Ho Chi Minh City University of Technology (HCMUT), Vietnam National University Ho Chi Minh (VNU-HCM) Thu Duc City Ho Chi Minh City 700000 Vietnam.
RSC Adv. 2025 Jul 10;15(30):24122-24136. doi: 10.1039/d5ra03370e.
Recovering phosphorus (PO ) and nitrogen (NH ) from swine wastewater is critical because their excess release can trigger eutrophication, severely harming aquatic ecosystems. This study introduces a pioneering fluidized-bed homogeneous crystallization (FBHC) process for single-step co-recovery of PO and NH . The method ensures compliance with discharge standards and produces a reusable nutrient product. Preliminary jar-test experiments were performed to identify the feasibility of struvite (MgNHPO·6HO) precipitation and to define the appropriate range for key operational parameters. Subsequently, operational parameters including pH, reaction time, up-flow velocity, cross-sectional loading, and bed height were systematically optimized. Under optimal conditions with a working medium at pH 9, reaction time of 24 min, up-flow velocity of 36 m h, cross-sectional loading of 0.27 kg m h, and bed height of 10 cm, the total removal efficiencies reached 97.42% for PO and 86.55% for NH . The corresponding crystallization ratios were 95.55% and 83.18%, respectively. The FBHC process exhibited high crystallization efficiency (>95%), contributing to reduced impurity levels and improved energy efficiency compared to conventional fluidized bed and chemical precipitation methods. The recovered product was identified as high-purity struvite (94.3%), predominantly comprising particles smaller than 0.75 mm. These results demonstrate the effectiveness of the FBHC strategy for simultaneous nutrient removal and resource recovery through the production of a value-added fertilizer.
从猪废水中回收磷（PO ）和氮（NH ）至关重要，因为它们的过量排放会引发富营养化，严重损害水生生态系统。本研究引入了一种开创性的流化床均相结晶（FBHC）工艺，用于一步法同时回收PO 和NH 。该方法确保符合排放标准，并生产出可重复使用的营养产品。进行了初步的烧杯试验，以确定鸟粪石（MgNHPO·6HO）沉淀的可行性，并确定关键操作参数的合适范围。随后，系统地优化了包括pH值、反应时间、上流速度、横截面负荷和床层高度在内的操作参数。在最佳条件下，工作介质pH值为9，反应时间为24分钟，上流速度为36 m h，横截面负荷为0.27 kg m h，床层高度为10 cm，PO 的总去除效率达到97.42%，NH 的总去除效率达到86.55%。相应的结晶率分别为95.55%和83.18%。与传统流化床和化学沉淀法相比，FBHC工艺表现出高结晶效率（>95%），有助于降低杂质水平并提高能源效率。回收的产品被鉴定为高纯度鸟粪石（94.3%），主要由小于0.75 mm的颗粒组成。这些结果证明了FBHC策略通过生产增值肥料同时去除营养物和回收资源的有效性。
