Modelling multiple mineral precipitation in anaerobic digester liquor.
Modelling multiple mineral precipitation in anaerobic digester liquor.
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模拟厌氧消化液中的多种矿物质沉淀。
DOI：
10.1016/s0043-1354(03)00173-8
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发表时间：
2003
期刊：
影响因子：
12.8
通讯作者：
G. Ekama
中科院分区：
文献类型：
--
作者：
P. van Rensburg;E. Musvoto;M. Wentzel;G. Ekama
在厌氧消化的初级和废活性污泥混合物的输送和处理中，已经经历了矿物质沉淀问题。本文介绍了对开普敦市污水处理厂厌氧消化液中矿物沉淀的实验研究（南非开普敦），并应用三阶段（水/固体/气体）物理和化学过程动力学模型由Musvoto等人开发。（Water Res.34（2000）1857; Water Res.34（2000）1868; Water SA 26（4）（2000）417）中所述的方法与实验数据进行比较。从实验研究和理论建模中，除其他外，得出以下结论：（i）在实验测量数据和理论预测数据之间存在密切的相关性，（ii）沉淀的主要矿物是鸟粪石，具有少量的无定形磷酸钙和可忽略的纽铍石、方解石和菱镁矿，（iii）当从ADL中损失CO2时，鸟粪石的沉淀受pH增加的控制，（iv）ADL最初相对于鸟粪石是不饱和的，但在pH>7.3-7.7时变得过饱和，（v）鸟粪石沉淀的速率和质量受pH增加速率和初始Mg浓度控制，以及（vi）三种-相动力学模型能够准确地模拟多种矿物竞争相同物种的时间依赖性沉淀数据，并允许以综合的方式同时从单一矿物中确定多种矿物的比沉淀速率。批量试验一些操作策略，以尽量减少鸟粪石沉淀的建议。
Mineral precipitation problems have been experienced with the conveyance and treatment of anaerobically digested primary and waste activated sludge blends. This paper describes an experimental investigation into mineral precipitation in anaerobic digester liquor (ADL) from the Cape Flats (CF) Wastewater Treatment Plant (WWTP) (Cape Town, South Africa), and application of the three-phase (aqueous/solid/gas) physical and chemical processes kinetic model developed by Musvoto et al. (Water Res. 34 (2000) 1857; Water Res. 34 (2000) 1868; Water SA 26(4) (2000) 417) to the experimental data. From the experimental investigation and theoretical modelling, it is concluded inter alia that: (i) there is a close correlation between experimental measured and theoretically predicted data, (ii) the dominating mineral that precipitates is struvite, with small amounts of amorphous calcium phosphate and negligible newberyite, calcite and magnesite, (iii) the precipitation of struvite is governed by the increase in pH when CO2is lost from the ADL, (iv) the ADL is initially undersaturated with respect to struvite, but becomes supersaturated at pH>7.3–7.7, (v) the rate and mass of struvite precipitation are controlled by the rate of pH increase and the initial Mg concentration and (vi) the three-phase kinetic model is able to simulate accurately the time dependent precipitation data for multiple minerals competing for the same species and allows determination of specific precipitation rates for a number of minerals simultaneously in an integrated manner from a single batch test. Some operational strategies to minimise struvite precipitation are proposed.