CALAGUA - Unidad Mixta UV-UPV, Institut Universitari d'Investigació d'Enginyeria de l'Aigua i Medi Ambient - IIAMA, Universitat Politècnica de València, Camí de Vera s/n, 46022 Valencia, Spain.
CALAGUA - Unidad Mixta UV-UPV, Institut Universitari d'Investigació d'Enginyeria de l'Aigua i Medi Ambient - IIAMA, Universitat Politècnica de València, Camí de Vera s/n, 46022 Valencia, Spain.
Sci Total Environ. 2019 Jul 1;672:88-96. doi: 10.1016/j.scitotenv.2019.03.485. Epub 2019 Apr 1.
Practical recovery of a non-renewable nutrient, such as phosphorus (P), is essential to support modern agriculture in the near future. The high P content of urine, makes it an attractive source for practicing the recovery of this crucial nutrient. This paper presents the experimental results at pilot-plant scale of struvite crystallisation from a source-separated urine stream using two different magnesium sources, namely magnesium chloride and seawater. The latter was chosen as sustainable option to perform P-recovery in coastal areas. Real seawater was used to assess in a more realistic way its efficiency to precipitate P as struvite, since its composition (with noticeable concentration of ions such as Ca, SO, Na, …) could lead to the formation of impurities and other precipitates. 0.99 g of struvite was obtained per litre of urine irrespective of the operational conditions tested. In all tested conditions, precipitation efficiencies exceeded 90% and recovery efficiencies were higher than 87%, with an average struvite crystal size higher than 110 μm (and up to 320 μm, depending on the experimental conditions) in the harvested struvite samples. Almost pure struvite was obtained when MgCl was used as precipitant, while amorphous calcium phosphate and other impurities appeared in the precipitates using seawater as magnesium source. However, the lower settling velocity of the amorphous precipitates in comparison with the struvite precipitates suggests that their separation at industrial scale could be relatively straightforward.
在不久的将来，要支持现代农业，就必须切实回收不可再生营养物质，如磷（P）。尿液中的高磷含量使其成为回收这种关键营养物质的理想来源。本文介绍了在中试规模下，从源分离尿液中使用两种不同的镁源（即氯化镁和海水）进行鸟粪石结晶的实验结果。选择后者作为在沿海地区进行磷回收的可持续选择。使用实际海水，以更现实的方式评估其作为鸟粪石沉淀磷的效率，因为其组成（如 Ca、SO、Na 等离子的显著浓度）可能导致杂质和其他沉淀物的形成。 无论测试的操作条件如何，每升尿液都可获得 0.99 g 的鸟粪石。在所有测试条件下，沉淀效率均超过 90%，回收率均高于 87%，收获的鸟粪石样品中的鸟粪石晶体平均粒径大于 110 μm（取决于实验条件，最大可达 320 μm）。当使用 MgCl 作为沉淀剂时，几乎可以获得纯鸟粪石，而当使用海水作为镁源时，在沉淀物中会出现无定形磷酸钙和其他杂质。然而，与鸟粪石沉淀物相比，无定形沉淀物的沉降速度较慢，这表明在工业规模上对其进行分离可能相对简单。
