Struvite Precipitation Offers Effective Method for Nitrogen and Phosphorus Recovery from Biogas Slurry

Strategic Insights -

Researchers at Jiangsu Province and Chinese Academy of Sciences have discovered that struvite precipitation is an efficient method for recovering nitrogen (N) and phosphorous (P) from biogas slurry. This breakthrough has significant implications for agriculture, as the recovered N and P can be used as a slow-release fertilizer. The study found that using magnesium chloride as a magnesium source resulted in higher N and P recovery efficiency compared to magnesium oxide. The optimal reaction conditions for struvite recovery were determined to be pH 10, a reaction time of 20 minutes, a stirring rate of 200 rpm, and a Mg/P/N ratio of 1.2:1.0:1.0. This resulted in N and P recovery rates of 81.83% and 99.67%, respectively.

Key Takeaways:

  • Struvite precipitation is an effective method for recovering N and P from biogas slurry, with a potential application as a slow-release fertilizer in agriculture.
  • The use of magnesium chloride as a magnesium source resulted in higher N and P recovery efficiency compared to magnesium oxide.
  • The optimal reaction conditions for struvite recovery were found to be pH 10, a reaction time of 20 minutes, a stirring rate of 200 rpm, and a Mg/P/N ratio of 1.2:1.0:1.0.
  • The recovered N and P can be used to improve the quality-related parameters of vegetables, such as fresh weight, soluble sugar, and soluble protein.
  • The application of struvite precipitated from biogas slurry in plant cultivation has great potential and lays a solid foundation for the resourceful recovery and utilization of biogas slurry.

Statistics:

  • N and P recovery rates of 81.83% and 99.67%, respectively, were achieved using the optimal reaction conditions (pH 10, a reaction time of 20 minutes, a stirring rate of 200 rpm, and a Mg/P/N ratio of 1.2:1.0:1.0).
  • The proportion of struvite in the fertilizer increased by 194.47%, 46.13%, and 82.42% for fresh weight, soluble sugar, and soluble protein in bock choy (* * Brassica chinensis* * ), respectively.
  • Water celery (* * Oenanthe javanica* * (Blume) DC.) quality-related parameters improved with an increasing proportion of struvite, including soluble sugar (27.90 mg·g[superscript]-1) and soluble protein (42.20 mg·g[superscript]-1).

Sources:

  • A Full Chain of Applying Struvite Recovered from Biogas Slurry to Promote Vegetable Growth. Agriculture, 2025,15(13):1352.
  • Jiangsu Agriculture Science And Technology Innovation Fund
  • Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing 210014, People's Republic of China.