Analysis of Struvite Precipitation in Real and Synthetic Liquors

Doyle, James; Philp, R. Paul; Churchley, John; Parsons, Simon A.

doi:10.1205/095758200531023

Cited by 49 publications

(43 citation statements)

References 26 publications

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“…Most of the studies [20][21][22] on struvite and calcium phosphate crystallization have been performed on pure synthetic medium containing only the ions directly involved in their composition. Real influents have also been studied but with lower ionic strength compared to the swine wastewater after P dissolution.…”

Section: Introductionmentioning

confidence: 99%

Optimization of struvite precipitation in synthetic biologically treated swine wastewater—Determination of the optimal process parameters

Capdevielle

Sýkorová

Biscans

et al. 2013

Journal of Hazardous Materials

137

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-Line Daumer. Optimization of struvite precipitation in synthetic biologically treated swine wastewater -Determination of the optimal process parameters. Journal of Hazardous Materials, Elsevier, 2013Elsevier, , vol. 244-245, pp. 357-369. <10.1016Elsevier, /j.jhazmat.2012 h i g h l i g h t sStruvite precipitation is mainly influenced by the quantity of MgO added. Optimized parameters favoured struvite formation despite of high [Ca 2+ ] without adding other reagents. 90% of the total dissolved phosphorus is recovered as large crystals of struvite. Raman spectroscopy and solid dissolution show co-precipitation of ACP and presence of CaCO 3 in solid.Keywords: Struvite P-recovery MgO Calcium phosphate Swine wastewater Raman a b s t r a c t A sustainable way to recover phosphorus (P) in swine wastewater involves a preliminary step of P dissolution followed by the separation of particulate organic matter. The next two steps are firstly the precipitation of struvite crystals done by adding a crystallization reagent (magnesia) and secondly the filtration of the crystals. A design of experiments with five process parameters was set up to optimize the size of the struvite crystals in a synthetic swine wastewater. More than 90% of P was recovered as large crystals of struvite in optimal conditions which were: low Mg:Ca ratio (2.25:1), the leading parameter, high N:P ratio (3:1), moderate stirring rate (between 45 and 90 rpm) and low temperature (below 20• C).These results were obtained despite the presence of a large amount of calcium and using a cheap reactant (MgO). The composition of the precipitates was identified by Raman analysis and solid dissolution. Results showed that amorphous calcium phosphate (ACP) co-precipitated with struvite and that carbonates were incorporated with solid fractions.

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Section: Introductionmentioning

confidence: 99%

Optimization of struvite precipitation in synthetic biologically treated swine wastewater—Determination of the optimal process parameters

Capdevielle

Sýkorová

Biscans

et al. 2013

Journal of Hazardous Materials

137

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“…One study shows that digested sludge pipe line's bore was reduced from 0.3 to 0.15 meter due to formation of struvite [8]. Another case shows that in 12 weeks, a 150 mm pipe made of rubber reduced to 60 mm in the discharge line of centrate [9]. Although struvite might be considered as a main problem occurring in wastewater treatment plants, it can be used in the production of fertilizers and soil conditioners [6].…”

Section: Introductionmentioning

confidence: 99%

“…Stirring and aeration will increase the pH of the solution through loss of CO 2 which is a favorable condition for struvite formation [12]. The simplest methods for inducing struvite formation are controlling pH level and magnesium concentration [9]. The purpose of this research is to assess the formation potential of struvite by mixing synthetic centrate and reject water from desalination.…”

Section: Introductionmentioning

confidence: 99%

Use of Desalinated Reject Water as a Source of Magnesium for Phosphorus Recovery

Fattah¹,

Shabani²,

Ahmed³

2013

IJCEA

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Abstract-In this study, the formation potential of struvite has been assessed using synthetic centrate mixed with reject water of a local desalination plant. NH 4 H 2 PO 4 , MgCl 2 .6H 2 O, and NH 4 Cl were mixed in specific concentrations to simulate centrate of a wastewater treatment plant coming from centrifuge of anaerobic digesters. Due to the lack of adequate magnesium in domestic wastewater, the prepared synthetic centrate was further mixed with the reject water of MED and RO units of the desalination plant since it is rich in magnesium which is required for formation of struvite. Significant removal of phosphorus was observed through precipitation of phosphorus compounds after stirring the samples in a batch reactor.

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“…Sludge digestion also releases ammonia due to protein degradation (Henze et al 2000). The released phosphorus may spontaneously bind with major polyvalent ions such as Mg 2+ , calcium (Ca 2+ ) and ammonia nitrogen to form minerals such as struvite and calcium phosphate (Doyle et al 2000, Ohlinger et al 1998). On the other hand, when chemical precipitation is involved in the primary treatment, iron (Fe 3+ ) will bind with phosphorus to form iron phosphate (Tchobanoglous et al 2003).…”

Section: Plant-wide Wastewater Treatment Modellingmentioning

confidence: 99%

“…The released phosphorus binds with magnesium and calcium to form struvite and other metal phosphates (Doyle et al 2000, Ohlinger et al 1998). The centrate (reject water) containing residual soluble phosphate and ammonia nitrogen is recycled upstream to the inlet of the plant, thus increasing the load of nutrients on the activated sludge process.…”

Section: Introductionmentioning

confidence: 99%

Dynamic modelling of minerals precipitation in wastewater treatment

Mbamba¹

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In wastewater treatment, there is an increasing focus on nutrient and energy recovery and a reduction in energy consumption to counter climate change. Because of this, integrated mathematical modelling platforms are required to support plant-wide developments making use of emerging, resilient and environmental-friendly technologies. A reliable model description of a wastewater treatment plant should include both biology and physico-chemistry. However, existing standard models used across the wastewater sector have a biological focus with over-simplified descriptions of important physicochemistry, especially with minerals precipitation which is a very important class of physicochemical reactions.As part of development of a more widely applicable physicochemical framework, this thesis sought to identify a suitable minerals precipitation modelling approach that could give reasonable results in mainstream use with wastewater treatment. This research aim was approached in three steps. Firstly a review of available modelling approaches suggested a simple equilibrium kinetic-based modelling approach could be feasible. This approach was then validated in a simple system of calcite in synthetic solutions using pH titration experiments with the reliable Constant Composition Method (CCM).Further statistical analysis focused on clarifying key environmental factors that influence calcite precipitation to determine whether these are necessary to include in a model. Secondly, the proposed model approach was further tested on different types of wastewater and for multiple parallel precipitation reactions. Experiments included dynamic titration or aeration with synthetic wastewater and real wastewater. Thirdly, the general physicochemical modelling approach was implemented in a plant-wide platform together with standard biological models, namely activated sludge model No 2 (ASM2d) and Anaerobic Digestion Model No. 1 (ADM1). The plant-wide model evaluation compared simulations with real data from a full-scale wastewater treatment plant, and used steadystate, dynamic and scenario analyses to test the model performance.Experimental evidence for calcite precipitating in synthetic aqueous solutions, suggested that minerals precipitation kinetics could be reliably described with a 1 st order dependency on mineral Further testing for multi-species systems in real wastewater indicated that precipitation was dominated by the mineral struvite, forming together with varied and minor amounts of calcium phosphate and some calcium carbonate. Kinetic rate coefficients (kcryst), which were statistically fitted, were generally in the range 0.35-11.6 h -1 with 95% confidence intervals of 10-80% relative.The results confirmed that the baseline model approach provided a statistically good fit of measured pH, dissolved calcium, magnesium, total inorganic carbon and phosphate. With this application, the precipitation modelling approach offered the advantage of only requiring a minimal number of empirical fitted parameters (kcryst values), res...

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Analysis of Struvite Precipitation in Real and Synthetic Liquors

Cited by 49 publications

References 26 publications

Optimization of struvite precipitation in synthetic biologically treated swine wastewater—Determination of the optimal process parameters

Optimization of struvite precipitation in synthetic biologically treated swine wastewater—Determination of the optimal process parameters

Use of Desalinated Reject Water as a Source of Magnesium for Phosphorus Recovery

Dynamic modelling of minerals precipitation in wastewater treatment

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