Struvite Precipitation Research Articles

Improving Prediction of Nutrient Recovery via Struvite Precipitation from Organic Waste Digestate

Improving Prediction of Nutrient Recovery via Struvite Precipitation from Organic Waste Digestate

Phosphorus removal and recovery from water and wastewater by the struvite crystallization

The precipitation of phosphorus naturally present in water, in the form of struvite, constitutes an interesting alternative for the phosphate water treatment. In this context, the main objective of the present study is to follow the crystallization of struvite, in a stirred tank, from real phosphated water (wastewater and natural water) at 25°C and at optimum pH 8.5 and to study the effect of environmental conditions on the crystallization stages (nucleation and crystal growth) and the morphology of struvite crystals.Various analytical methods (spectrophotometry, FTIR, SEM and XRD) were used to characterize the solid and liquid phases. In the light of the results obtained in this investigation, it appears that the precipitates formed in all the samples of treated waters were identified as ammonium magnesium phosphate (i.e. struvite). The precipitation of struvite in water allowed a significant elimination of phosphorus (up to 70%). On the other hand, the SEM analysis was able to highlight the presence of large clusters of large struvite crystals up to 146.8µm, as in the case of the precipitation of struvite with wastewater, where the conversion rate was the highest. The supersaturation ratio is the most important factor influencing the crystallization process.

Techno-economic analysis of nutrient recovery from urine: Centralized treatment of hydrolyzed urine vs. decentralized treatment of fresh urine

The centralized process integrating “Thermal NH3 stripping → Na-chabazite adsorption → Struvite precipitation” has been proposed for nutrient recovery from hydrolyzed urine. Meanwhile, a decentralized approach involving Na-chabazite and biochar adsorption has been suggested for fresh urine, followed by urea hydrolysis and the subsequent centralized integration of struvite precipitation and thermal stripping. However, a systematic comparison of nutrient recovery processes for fresh and hydrolyzed urine, evaluating both technical viability and financial feasibility, is lacking. This study addresses the gap by thoroughly examining both scenarios over a 30-year project, using Université Laval as a case study. It provides a comprehensive roadmap for techno-economic assessment, offering guidance for evaluating nutrient recovery processes prior to scaling up. The decentralized process achieved higher recovery efficiencies for nitrogen and phosphorus, at 89.4 % and 98.7 %, respectively. Financially, the decentralized scenario demonstrated its advantage in the lower initial investment requirement, thereby generating higher gross profits compared to the centralized scenario. As a result, it is projected to reach the break-even point in the 21st year, demonstrating its potential economic feasibility. Sensitivity analysis indicated that a 20 % increase in urine inflow rate and the price of urea-enriched biochar could further enhance the economic viability of both processes. Beyond financial considerations, both scenarios have the potential to reducing the contaminant loading rate in the downstream wastewater treatment plants and promote nutrient recovery and recycling.

Simultaneous adsorption of ammonia nitrogen and phosphate on electro-assisted magnesium/aluminum-loaded sludge-based biochar and its utilization as a plant fertilizer.

Herein, Mg/Al-loaded sludge-based biochar was prepared via electro-assisted impregnation. The structure and chemical analysis of modified sludge-based biochar (MgSBC-0.5(@Al) showed that the material was loaded with MgO and Al2O3. The specific surface area of MgSBC-0.5(@Al) was 11.27 times higher than that of unmodified sludge-based biochar (SBC). The simultaneous adsorption performance of MgSBC-0.5(@Al for ammonia nitrogen (NH4+-N) and phosphate phosphorus (PO43--P) was studied. The maximum adsorption capacities of MgSBC-0.5(@Al for NH4+-N and PO43--P at 298 K were 65.19 and 92.10 mg·g-1, respectively, 4.45 and 6.28 times higher than those of SBC. The external and internal elemental compositions of the modified and unmodified biochar specimens were quantitatively characterized using inductively coupled plasma mass spectrometry, X-ray photoelectron spectroscopy, and X-ray fluorescence spectrometry. The results emphasized the importance of Mg-loading for NH4+-N and PO43--P capture. MgO was mainly loaded on the surface of biochar, enabling adsorption through chemical reactions. Analysis showed that the adsorption of NH4+-N and PO43--P on the modified biochar proceeded simultaneously through multiple mechanisms. Particularly, the adsorption of NH4+-N and PO43--P occurred through the precipitation of struvite and physical adsorption, with PO43--P also adsorbed through the formation of MgHPO4 and CaHPO4. Other data indicated that Al, Ca, and Fe had a trapping effect on the adsorbate. Importantly, the biochar after adsorption could be used as a soil amendment.

Optimization of struvite from sewage sludge ash as phosphorus source.

Phosphorus is an essential macronutrient for crop production. Struvite precipitation and reuse from phosphorus-rich sewage sludge are cost-effective measures to improve phosphorus utilization efficiency and decrease its negative environmental impact. In this study, the objectives were to optimize the phosphorus extraction (using sulfuric acid) and recovery (as struvite) processes and determine the most appropriate process conditions using RSM. This was done by evaluating the effect of different parameters such as acid concentration (mol/l) (0.02 to 0.8), H2SO4/ISSA ratio (liquid/solid) (20 to 150ml/g), and time (0.5 to 4h) for leaching tests and N: P ratio (1 to 2), Mg: P ratio (1 to 2), and pH (8 to 11) for struvite precipitation. The optimization of the factors affecting PO43--P extraction from SSA by acidic leaching showed that applying 0.5mol/l H2SO4 and 57ml/g L/S ratio at 2h achieved the highest PO43--P extraction (99.8%). The extraction of phosphorus also leached heavy metals; however, using a cation exchange resin, it was possible to effectively remove heavy metals from P-rich solutions. The optimal phosphorus recovery as struvite (98.5%) was achieved at the lowest pH and N/P ratio, while an increase in Mg/P ratio from 1 to 2 positively affected phosphorus recovery. The obtained struvite had a high content 94.6%, and the heavy metal content in struvite was lower than the value of standard, so that the obtained struvite sample can be used as fertilizer.

Nutrient recovery from urine: Urea adsorption onto biochar integrated with Na-chabazite as urease inhibitor

This study presents an innovative technical integration for concomitant nutrient recovery from source-separated urine. While cation exchange is known for efficient K+ recovery, it faces competition due to the high molarity of NH4+ in hydrolyzed urine. This study proposes inhibiting urease activity to facilitate the recovery of K⁺ and urea from fresh urine. Na-chabazite was first proposed as a urease inhibitor in this study, reducing urease activity by 50 %. Wood biochar, with its high porosity (308.0 m²/g) and polar functional groups, shows a urea adsorption capacity of 25.4 mg/g, which can be further improved by steam activation. The isotherm analysis suggests that urea adsorption onto biochar follows a multi-layer adsorption process. Finally, an integrated process is suggested: "Na-chabazite and Biochar adsorption → urea hydrolysis → struvite precipitation + ammonia stripping-acid scrubbing", ensuring efficient recovery of urea, NH4+, PO43-, and K+ from source-separated urine.

Integrating Anaerobic Digestion With Struvite Production for Enhanced Nutrient Recovery, Pathogen Reduction, and Circularity in Manure Management

ABSTRACTIntroductionAnaerobic digestion (AD) is essential for manure management, generating biogas and nutrient‐rich digestate for organic fertilizer. However, improper digestate use can pose environmental risks. Recovering struvite, a magnesium ammonium phosphate (MAP) compound, from digestate provides a sustainable, controlled‐release fertilizer, supporting a circular economy in agriculture.Materials and MethodsThe study employed a two‐stage (liquid–solid) AD process using poultry, dairy, and swine manures, along with wasted corn silage. Digestates were sampled for physicochemical and biogas quality analyses, with feedstocks categorized into D1 and D2, and a composite (D3) formed for struvite characterization. Microbial populations were enumerated on selective media, and struvite mineral content was analysed via argon plasma emission spectrometry.ResultsThe digesters processing feedstock mixtures D1 and D2 achieved specific methane yields of 1.26 L/g CODs fed and 1.49 L/g CODs fed, with cumulative biogas production of 374 and 369 L, respectively, over four 77‐day cycles. The two‐stage AD process significantly reduced antibiotic‐resistant, Enterobacteriaceae and Enterococcus spp. Total ammoniacal nitrogen (TAN) recovery rates were high at 98%–99%, with a consistent struvite crystal mass of 0.67 g/10 mL, indicating the efficiency of this integrated process. The agronomic value of struvite was determined, indicating its potential utility as a fertilizer, and scanning electron microscopy analysis revealed diverse crystal structures, warranting further investigation into their implications for usage and storage.ConclusionThe results suggests that the two‐stage AD process efficiently transforms organic waste into high‐quality biogas, reduces antibiotic‐resistant bacteria, and facilitates nutrient recovery through struvite precipitation. This approach supports co‐digestion of multi‐substrates and promotes circular economy principles, with potassium or sodium phosphate enhancing struvite recovery for sustainable agriculture.

A new approach on the management of landfill leachate reverse osmosis concentrate: Solar distillation coupled with struvite recovery and biological treatment

The management of reverse osmosis (RO) concentrate remains a challenging task for operators of Landfill Leachates Treatment Plants. In this article we suggest an integrated treatment scheme for RO concentrate that combines solar distillation, struvite precipitation to reduce ammonia content of the distillate and biological treatment of the supernatant either with mixed cultures of bacteria or with microalgae. Experiments in a pilot-scale solar still, equipped with underfloor heating system, showed that the production rate of the distillate ranged up to 3.17 L/d m2. The distillate was characterized by elevated average concentrations of ammonium nitrogen; 2028 mg/L and 1358 mg/L in the two experiments conducted, respectively. A decreasing trend on concentrations of NH4+-N was noticed during these experiments, while the opposite was observed for COD. Struvite recovery experiments showed that the optimum Mg:NH4:PO3 ratio was that of 2:1:5.8. Under these conditions, the NH4+-N removal reached 88%. Further treatment of the process supernatant into a 4-L hybrid sequencing batch reactor with biocarriers and activated sludge achieved NH4+-N removal higher than 98% in Phases C and D, where 450 and 600 mL of supernatant were added, respectively. Similar removal was also observed in a 2-L bioreactor with microalgae Chlorella sorokiniana when 150 mL of struvite supernatant were added (Phase B) while further increase of the amount of added supernatant to 200 mL resulted to a sharp stop of NH4+-N consumption (Phase C). Calculations for a landfill serving 20,000 inhabitants and a daily RO concentrate production of 6 m3/d showed that the required area for the construction of the solar still was 1893 m2 and the volumes of the hybrid and the microalgae reactor were 54 m3 and 60 m3, respectively. The recovered solid material of struvite process, after characterization for heavy metals and organic micropollutants, could be reused to the fertilizers industry.

Multiple element approach to P recovery and recycling: A green and sustainable strategy by using fused magnesia waste ash

Recovery of phosphorus through controlling the crystallization of struvite (MgNH4PO4·6H2O), a slow-release fertilizer, is highly attractive, but costly if large amounts of magnesium and alkali have to be added. In this study, a strategy for synchronously recovering phosphorus and nitrogen resources from wastewater and magnesium resources from solid waste was proposed. We demonstrated the fused magnesia waste ash (FMWA), an industrial by-product of magnesia which might serve as a cost-effective source of magnesium and alkali. The results showed that a recovery efficiency of 93.0 % PO43− and 88.8 % NH4+ from synthetic wastewater and 46.6 % Mg2+ from the FMWA was achieved when the ratio of [Mg2+]:[NH4+]:[PO43−] was 1.8:1:1. The magnesium release potential of FMWA was 10 times more than that of other known magnesium-containing solid wastes, due to the process in electric melting furnace damaged the lattice structure of magnesite and converted magnesite to magnesia. XRD analysis showed that crystalline struvite was the major product. The undissolved components of FMWA (MgCO3, MgO and SiO2) acted as crystal seeds, increasing the particle size and accelerating struvite precipitation. The application of FMWA for phosphorus fixation can reduce costs by 98.3 % compared with MgCl2. This research paves the way for employing FMWA in efficient recovery of phosphorus from wastewater, simultaneously achieving the resource utilization of industrial waste.

Optimization of potassium (K) recovery via electrochemical precipitation of K-struvite upon magnesium addition in urine

Potassium (K)-struvite precipitation is a promising approach to K recovery but faces the critical challenge of co-precipitation of sodium (Na)-struvite mainly due to the addition of sodium hydroxide (NaOH) for pH adjustment. To avoid using NaOH, this study investigated the electrochemical addition of magnesium (Mg) and hydroxide ions for K-struvite recovery. Results showed that a high release rate of Mg and hydroxide ions in the electrolysis led to a Mg:Phosphorus (P) ratio higher than 1:1 and pH higher than 11.3, which however resulted in a decrease in the K recovery efficiency. Subsequent optimization experiments conducted in synthetic urine, diluted fivefold, maintained a process pH of 10.811.0, with a current density of 5 mA/cm2 and an electrode spacing of 20 mm. Under these conditions, K recovery efficiency reached 38 %, while P recovery efficiency reached 93 % after 30 minutes of electrolysis. Compared to chemical precipitation methods, electrochemical recovery exhibited a 41 % increase in K recovery efficiency and a 153 % increase in K-struvite:Na-struvite molar ratio in the precipitates. Furthermore, a predictive model was developed to estimate optimal K recovery time and energy consumption, showcasing the effectiveness of electrochemical Mg addition in urine for high-efficiency K recovery.

Nutrient recovery in wastewater treatment plants through biosolids and struvite precipitation: Case study in Panama City

This work assesses the nutrient recovery potential in Panama City’s wastewater facilities. Nutrients can be recovered by using biosolids, which are currently dumped in landfills, and by precipitating struvite from waste streams. The economic viability of four types of struvite reactors was analyzed. The installation of struvite systems is not profitable for the current discharge limit of 10 mg/l for P. However, for P limits of 4 mg/l and below, struvite systems would generate significant revenue due to savings in the chemicals needed to remove the excess of P. For a P limit of 4 mg/l, the best struvite reactor presented a payback time of 10 years and a return on investment of 13.68 %. It is concluded that in Panama, as in the rest of Latin American countries, nutrient discharge standards are currently too loose for struvite systems to become viable. Meanwhile, the use of biosolids is of particular interest as the standards for their use are already well developed. The use of biosolids from Panama City could supply 1.6 % of the consumption of fertilizers in the country. It was found that the quality of the biosolids that are produced in the region is satisfactory, and that the demand from potential users can be improved through composting the material.

Strategy of Nutrient Recovery from Domestic Wastewater Using Magnesium‐Modified Agricultural‐Waste‐Based Biochars

AbstractThis work presents a reasonable strategy of optimizing the N : P molar ratio of municipal wastewater to simultaneously restore N‐NH4+ and P‐PO43− via struvite precipitation employing biochar modified with magnesium as the seeding material. The phosphate removal efficiency and ammonium removal efficiency could reach up to 71 % and 100 %, respectively. The remaining phosphate can be restored by other techniques for low phosphate concentration input, such as electrocoagulation. The XRD patterns indicate the appearance of struvite with high nutrient contents including Mg, N and P in the resulting precipitate, suggesting its potential agricultural application. The biochar from rice husk and rice straw modified with MgCl2 solution via a simple procedure could be used as a new seeding material in struvite precipitation to simultaneously restore phosphate and ammonium from wastewater. It has been found that modifying with MgCl2 concentration of 0.5 M and 1 M were enough to improve 14.7 % and 26.5 % of the phosphate removal efficiencies of rice straw‐based and rice husk‐based biochar, respectively. Along with the highly compatible of the post‐precipitated product with soil amendment, the magnesium modified biochars from rice husk and rice straw were highly suitable for enhancing the restoration of phosphate and ammonium via struvite precipitation.

Treatment and nutrient recovery from landfill leachate by sequential persulfate oxidation and struvite precipitation: An evaluation of technical feasibility.

The technical feasibility of advanced oxidation process, in particular persulfate (PS) oxidation followed by struvite precipitation for landfill leachate treatment and nutrient recovery has been depicted in the current study. Furthermore, the impact of activation of PS with thermal and ultraviolet (UV) irradiation techniques on COD removal efficiency is also investigated. A maximum COD removal efficiency of 96% is accomplished at 65°C together with supply of UV irradiation. The impact of persulfate dose, pH, and PS/65°C/UV system on COD and biodegradability is also illustrated in the current study. Additionally, decomposition rate constant values are also ascertained in the present study. Afterwards, nutrient recovery using struvite precipitation is carried out for sustainable utilization of resources. Preliminary treatment of leachate with PS/65°C/UV system is greatly conducive to recovering high quality struvite crystals. Besides, 94.9%, 83.5%, and 91.3% of PO43- -P, NH4+ -N, and Mg2+ recovery efficiency attained respectively at pH 9.5 and 1.2:1:1 molar ratio of Mg2+: NH4+-N: PO43--P. Additionally, all the nutrient recovery studies are validated using chemical equilibrium model Visual MINTEQ. Later, bioavailable fraction of PO43--P in the recovered struvite is also investigated for utilization as fertilizer. The presence of Cu and Zn in the recovered struvite precipitate enhanced its economic value as a fertilizer. Since Cu and Zn are vital micronutrients for growth of plants. The low soluble values of recovered struvite precipitate confirmed its utilization as slow releasing fertilizer.

Nitrogen recovery from biogas slurry with high ammonia nitrogen concentration through struvite precipitation utilizing acid leaching solution of collophanite tailings

ABSTRACT The high concentration of ammonia nitrogen (NH4+) and chemical oxygen demand (COD) in biogas slurry pose great challenges to the efficiency of traditional wastewater treatment systems. Collophanite tailings are solid waste, characterized by significant concentrations of phosphorus (PO43-) and magnesium (Mg2+), represent a potential resource for the reduction and recovery of NH4+ in biogas slurry via struvite precipitation. This study systematically explored the optimal leaching parameters employing sulfuric acid for the extraction of PO43− and Mg2+ from collophanite tailings. The effect of [PO43-]:[NH4+] molar ratio and pH on the recovery of NH4+ in biogas slurry was investigated. The physicochemical properties of the precipitates were confirmed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and chemical analysis. Results suggested that the highest removal efficiency of NH4+ (88.5%) was achieved when employing a [PO43-]:[NH4+] molar ratio of 1.0 at pH 9.5. Evaluation of effluent quality demonstrates a significant enhancement in the biodegradability of the treated biogas slurry, evidenced by an increase in the COD/TN ratio increased from 2.1 to 10.4. Economic analysis shows that the net income would be approximately 21.33 USD/m3 for proposed produces. These findings underscore the potential of utilizing collophanite tailings for NH4+ recovery from biogas slurry.

Strategies for ammonia recovery from wastewater: a review

AbstractThe circular economy requires advanced methods to recycle waste matter such as ammonia, which can be further used as a fuel and a precursor of numerous value-added chemicals. Here, we review methods for the recovery of ammonia from wastewater with emphasis on biological and physicochemical techniques, and their applications. Biological techniques involve nitrification, denitrification, and anammox processes and the use of membrane bioreactors. Physicochemical techniques comprise adsorption, membrane filtration, ion exchange, chemical precipitation, ammonia stripping, electrochemical oxidation, photocatalytic oxidation, bioelectrochemical systems, and membrane hybrid systems. We found that nitrification and anammox processes in membrane bioreactors stand out for their cost-effectiveness, reduced sludge production, and energy efficiency. The use of struvite precipitation is an efficient, environmentally friendly, and recyclable method for ammonia removal. Membrane hybrid systems are promising for ammonia recovery, nutrient concentration, and wastewater treatment, with applications in fertilizer production and water purification. Overall, nitrogen removal ranges from 28 to 100%, and nitrogen recovery ranges from 9 to 100%.

A comparative study on UASB MF-OMBR and AnMF-OMBR treating slaughterhouse wastewater: Process performance, struvite precipitation, and economic evaluation

Up-flow anaerobic sludge blanket microfiltration osmotic membrane bioreactor (UASB MF-OMBR) is a cutting-edge technology derived from the anaerobic osmotic membrane bioreactor (AnOMBR). This study investigated long-term performance of an UASB MF-OMBR and an anaerobic microfiltration osmotic membrane bioreactor (AnMF-OMBR) comparatively focusing on process performance, membrane fouling, microbial community shift, struvite precipitation, and economic evaluation for the treatment of synthetic and real slaughterhouse wastewater (SSW and RSW). The UASB MF-OMBR achieved higher process performance regarding chemical oxygen demand (COD) removal (70 ± 1 %), methane yield (0.24 ± 0.03 L CH4 g−1 CODremoved) and NH4+-N rejection (85 ± 3 %). On the other hand, high COD and PO43−-P rejections were observed in both systems (>92 % and ∼98 %, respectively). The impact of the salinity build-up in the UASB MF-OMBR was the lower due to the bioreactor configuration. In addition, compared to the AnMF-OMBR, the better water fluxes were obtained in the UASB MF-OMBR, which can be attributed to the less membrane fouling. The results of precipitation modelling and Mg2+ measurement in the sludge of both bioreactors demonstrated that the struvite precipitation occurred during the forward osmosis (FO) operation was more often and in higher amounts in the AnMF-OMBR. The economic evaluation indicated that the specific produced permeate cost (SPC) with revenue was slightly lower for the UASB MF-OMBR than that of the AnMF-OMBR.

Fate of micropollutants in struvite production from swine wastewater with sacrificial magnesium anode

Struvite recovery shows significant potential for simultaneously recovering nitrogen (N) and phosphorus (P) from swine wastewater but is challenged by the occurrence and transformation of antibiotic residuals. Electrochemically mediated struvite precipitation with sacrificial magnesium anode (EMSP-Mg) is promising due to its automation and chemical-free merits. However, the fate of antibiotics remains underexplored. We investigated the behavior of sulfadiazine (SD), an antibiotic frequently detected but less studied than others within the EMSP-Mg system. Significantly less SD (≤ 5%) was co-precipitated with recovered struvite in EMSP-Mg than conventional chemical struvite precipitation (CSP) processes (15.0 to 50.0%). The reduced SD accumulation in struvite recovered via EMSP was associated with increased pH and electric potential differences, which likely enhanced the electrostatic repulsion between SD and struvite. In contrast, the typical strategies used in enhancing P removal in the EMSP-Mg system, including increasing the Mg/P ratio or the Mg-release rates, have shown negligible effects on SD adsorption. Furthermore, typical coexisting ions (Ca2+, Cl−, and HCO3−) inhibited SD adsorption onto recovered products. These results provide new insights into the interactions between antibiotics and struvite within the EMSP-Mg system, enhancing our understanding of antibiotic migration pathways and aiding the development of novel EMSP processes for cleaner struvite recovery.

Sustainable nutrient recovery through struvite precipitation from poultry and multi-substrate agricultural waste digestates

This study addresses the multifaceted challenges stemming from the excessive application of manure or digestate, with the aim of mitigating problems of storage, emissions, contamination and transportation. It presents a unique-protocol for efficiently recovering nutrients in the form of struvite, a pure, easy-to-use magnesium ammonium phosphate compound. The objective is to explore struvite production via mono-digestion of poultry manure and co-digestion of various organic wastes, including poultry, dairy, pig manures, and wasted corn silage. Crystals are synthesized under optimized conditions: magnesium/phosphorus ratio of 1.5, pH 9, and mixing at 240 rpm. The process achieves ≥95 % TAN-recovery in moisture-free form for various digestates, with a significant 61.5 % reduction in volatile-fatty-acids. Approximately 0.33–1 g struvite is produced per 10 mL digestate. The study suggests using disodium or monopotassium phosphate for practical implementation, demonstrating the versatility of digestates. Integrating this method into anaerobic digestion promotes the circular-economy and sustainable management of waste nutrients.

Application of physicochemical techniques to the removal of ammonia nitrogen from water: a systematic review.

Ammonia nitrogen is a common pollutant in water and soil, known for its biological toxicity and complex removal process. Traditional biological methods for removing ammonia nitrogen are often inefficient, especially under varying temperature conditions. This study reviews physicochemical techniques for the treatment and recovery of ammonia nitrogen from water. Key methods analyzed include ion exchange, adsorption, membrane separation, struvite precipitation, and advanced oxidation processes (AOPs). Findings indicate that these methods not only remove ammonia nitrogen but also allow for nitrogen recovery. Ion exchange, adsorption, and membrane separation are effective in separating ammonia nitrogen, while AOPs generate reactive species for efficient degradation. Struvite precipitation offers dual benefits of removal and resource recovery. Despite their advantages, these methods face challenges such as secondary pollution and high energy consumption. This paper highlights the development principles, current challenges, and future prospects of physicochemical techniques, emphasizing the need for integrated approaches to enhance ammonia nitrogen removal efficiency.

Electrochemical Recovery of N and P from Municipal Wastewater

Phosphorus, P, is a vital element of paramount importance for both humans and for the Environment. Wastewater contains often relatively high concentrations of P which can be recovered as crystalline struvite (MgNH4PO4·6H2O, MAP). This option is quite attractive in assisting sustainable development because struvite can be used as a slow-release fertilizer. Domestic wastewater is usually high in P and nitrogen, N, but relatively poor in magnesium, Mg. It is necessary to develop low-cost solutions for the enrichment of wastewater with Mg. In the present work, sacrificial magnesium anodes were used, which dissolve upon anodic polarization, releasing sufficient magnesium for the selective precipitation of MAP. The application of constant current between two electrodes of which the anode is a low-cost magnesium cylindrical rod (4 cm2 exposed surface area) and the other a platinum cathode electrode, both immersed in ammonium phosphate solutions, without adjustment of the solution pH, was investigated. Constant current density over the range 10–100 A·m−2, between the Mg- Pt electrodes immersed in solutions of ammonium hydrogen phosphate of exactly known initial concentration, was applied using a potentiostat. In the presence of sodium chloride solutions, on the magnesium anode and in the bulk solution, Mg(OH)2 (brucite) formed because of the passivation of the Mg electrode. In dilute ammonium hydrogen phosphate solutions, the magnesium anode dissolution resulted in struvite precipitation, even at a low applied current (10 mA). Struvite crystals with an average size of 20 μm were precipitated. The behavior of the cell for the electrolyte solutions used was Faradaic as long as the surface coverage of the anode was relatively low. The anodic dissolution of Mg resulted in high pH values (pH 11) eliminating the need for alkali addition.