Tampere University of Technology, Laboratory of Chemistry and Bioengineering, P.O. 541, FI-33101, Tampere, Finland.
Tampere University of Technology, Laboratory of Materials Science, P.O. 589, FI-33101, Tampere, Finland.
J Environ Manage. 2018 Apr 15;212:433-439. doi: 10.1016/j.jenvman.2018.02.027. Epub 2018 Feb 22.
Improving environmental protection and finding sustainable and renewable resources of nutrients are core issues in circular bioeconomy. Thus, this study evaluated the efficiency of recovering struvite, MgNHPO·6HO, from different agro-industrial wastewaters (four highly loaded reject waters of anaerobically co-digested agro-industrial waste and a raw swine slurry) and assessed the quality of recovered struvite crystals and their reusability as fertilizer. The efficiency of crystallization (E 40-80%) and amount of struvite in the precipitate (P 55-94%) highly varied due to the characteristics of influent wastewaters, particularly to the content of competing elements, such as alkaline and heavy metals and total solids (TS). In particular, E (94, 75, 61%) and P (76, 66, 48%) decreased at increasing TS (0.57, 0.73, 0.99%), demonstrating the hindering effect of solid content on struvite recovery and quality. According to X-ray diffraction analysis, the structure of all isolated samples corresponded to crystalline, orthorhombic struvite, which exhibited high purity (32-48 g/kg N, 114-132 g/kg P, and 99-116 g/kg Mg) containing only a few foreign elements, whose amount depended on the characteristics of the influent wastewater. All struvite contained other plant macronutrients (K, Ca) and many micronutrients (Fe, Na, Cu, Mn, Co, Zn) that further enhance its agronomic value. Therefore, this study showed that struvite can be successfully recovered from a wide range of highly loaded agroindustrial wastewaters, and that the quality of the recovered struvite could be suitable for reuse in agriculture.
提高环境保护水平并寻找可持续和可再生的营养物质资源是循环生物经济的核心问题。因此，本研究评估了从不同农业工业废水中（四种高度负荷的厌氧共消化农业工业废水和原始猪粪浆）回收鸟粪石（MgNHPO·6HO）的效率，并评估了回收鸟粪石晶体的质量及其作为肥料的再利用性。结晶效率（E40-80%）和沉淀物中的鸟粪石量（P55-94%）因进水废水的特性而有很大差异，特别是由于竞争元素（如碱性和重金属以及总固体（TS））的含量。特别是，E（94、75、61%）和 P（76、66、48%）随着 TS（0.57、0.73、0.99%）的增加而降低，表明固体含量对鸟粪石回收和质量的阻碍作用。根据 X 射线衍射分析，所有分离样品的结构均对应于结晶正交鸟粪石，其纯度高（32-48g/kg N、114-132g/kg P 和 99-116g/kg Mg），仅含有少量外来元素，其含量取决于进水废水的特性。所有鸟粪石都含有其他植物大量营养素（K、Ca）和许多微量元素（Fe、Na、Cu、Mn、Co、Zn），这进一步提高了其农业价值。因此，本研究表明可以从广泛的高负荷农业工业废水中成功回收鸟粪石，并且回收鸟粪石的质量可以适合农业再利用。
