Xia Hui, Pei Wentao, Huang Kui, Shi Jiwei, Huan Guohui
School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China; Ministry of Education Engineering Research Center of Water Resource Comprehensive Utilization in Cold and Arid Regions 730070, China.
School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China.
Waste Manag. 2025 Aug 1;204:114926. doi: 10.1016/j.wasman.2025.114926. Epub 2025 May 30.
The conventional magnesium ammonium phosphate (MAP) crystallization method for phosphorus recovery from sewage sludge faces significant challenges, including high operational costs and limited inorganic phosphorus release efficiency. To address these limitations, this study introduces an innovative integrated approach combining vermicomposting with MAP crystallization (VCMAP). The results showed that vermicomposting pretreatment significantly enhanced nutrient availability, yielding a 73.58 % increase in ammonium nitrogen and a 16.32 % increase in orthophosphate concentration compared to raw sludge. In addition, fresh vermicompost samples exhibited superior performance, releasing 96.65 % more orthophosphate than their air-dried counterparts. Response surface methodology (RSM) identified the optimal recovery conditions from vermicompost using MAP as pH = 9.3, Mg: N: P = 1.1:1.3:1, and agitation time (AT) of 100 min. Notably, calcium ions exerted a more pronounced influence on the VCMAP process, compared to iron and aluminum ions. The integrated VCMAP system demonstrated remarkable efficiency, achieving a 226 % increase in struvite recovery (8.83 kg/t sludge) and capturing 20.28 % of total phosphorus within 10 days of vermicomposting pretreatment. Moreover, the process exhibited a negative carbon footprint of -56.32 kg CO/t sludge, indicating its potential for carbon credit generation. These findings establish the VCMAP as a promising low-carbon technology for enhanced phosphorus recovery from sewage sludge, offering significant improvements over conventional MAP approaches.
传统的磷酸镁铵（MAP）结晶法从污水污泥中回收磷面临着重大挑战，包括运营成本高和无机磷释放效率有限。为了解决这些限制，本研究引入了一种创新的综合方法，将蚯蚓堆肥与MAP结晶（VCMAP）相结合。结果表明，蚯蚓堆肥预处理显著提高了养分有效性，与原始污泥相比，铵态氮增加了73.58%，正磷酸盐浓度增加了16.32%。此外，新鲜蚯蚓堆肥样品表现出更好的性能，其释放的正磷酸盐比风干后的样品多96.65%。响应面法（RSM）确定了以MAP从蚯蚓堆肥中回收磷的最佳条件为pH = 9.3、Mg:N:P = 1.1:1.3:1和搅拌时间（AT）为100分钟。值得注意的是，与铁离子和铝离子相比，钙离子对VCMAP过程的影响更为显著。集成的VCMAP系统显示出显著的效率，在蚯蚓堆肥预处理10天内，鸟粪石回收率提高了226%（8.83 kg/t污泥），捕获了总磷的20.28%。此外，该过程的碳足迹为-56.32 kg CO/t污泥，表明其具有产生碳信用的潜力。这些发现表明VCMAP是一种有前途的低碳技术，可提高从污水污泥中回收磷的效率，与传统的MAP方法相比有显著改进。
