Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
J Environ Sci (China). 2018 Aug;70:144-153. doi: 10.1016/j.jes.2017.11.029. Epub 2017 Dec 11.
Struvite crystallization has been considered a promising approach to recover phosphorus from wastewater. However, its practical application is limited, probably because of the high cost of magnesium (Mg). In this study, a comprehensive economic analysis was conducted using five Mg sources (MgCl, MgSO, MgO, Mg(OH), and bittern) during the operation of a pilot-scale fluidized bed reactor (FBR), using swine wastewater as the case matrix. First, the economic operating conditions were investigated, and subsequently, the performance and the costs of the five Mg sources were compared. The results indicated that the FBR could be operated most economically at pH of 8.5 and Mg to phosphorus (Mg/P) molar ratio of 1.5. Under these conditions, no significant differences in phosphorus removal and product quality could be found between the five Mg sources. Selecting the most economical Mg source was thus highly dependent on the prices of the reagents and Mg sources. Low-solubility Mg sources were preferable when NaOH was priced higher, while high-solubility Mg sources proved more economical when HNO was expensive. The bittern was the most economical choice only when the distances for total inorganic orthophosphate removal and struvite recovery were shorter than 40 and 270km, respectively. The current study provides an overview of the economic selection of an Mg source, which can help reduce the cost of struvite crystallization.
鸟粪石结晶法被认为是从废水中回收磷的一种很有前途的方法。然而，其实际应用受到限制，可能是因为镁（Mg）的成本较高。在本研究中，使用猪废水作为案例矩阵，在中试流化床反应器（FBR）运行期间使用五种镁源（MgCl、MgSO、MgO、Mg(OH)和卤水中）进行了综合经济分析。首先，研究了经济运行条件，然后比较了五种镁源的性能和成本。结果表明，FBR 可以在 pH 值为 8.5 和 Mg 与磷（Mg/P）摩尔比为 1.5 的条件下最经济地运行。在这些条件下，五种镁源在磷去除率和产品质量方面没有显著差异。因此，选择最经济的镁源高度依赖于试剂和镁源的价格。当 NaOH 的价格较高时，低溶解度的镁源更可取，而当 HNO 昂贵时，高溶解度的镁源则更经济。只有当总无机正磷酸盐去除和鸟粪石回收的距离分别短于 40 和 270km 时，卤水才是最经济的选择。本研究概述了镁源的经济选择，这有助于降低鸟粪石结晶的成本。
