This page has only limited features, please log in for full access.
The recycling of nutrients from wastewater and their recovery in the form of valuable products is an effective strategy to accelerate the circular economy concept. Phosphorus recovery from wastewater by struvite crystallization (MgNH4PO4·6H2O) is one of the most applied techniques to compensate for the increasing demand and to slow down the depletion rate of phosphate rocks. Using low-cost magnesium sources, such as seawater, improves the financial sustainability of struvite production. In this study, the potential of seawater for struvite crystallization versus the commonly used magnesium source, MgCl2, was tested by crystal growth and kinetic experiments. The impact of ammonium concentration, magnesium concentration and pH on the growth kinetics of struvite in synthetic and real reject water were studied. The results showed that simultaneous precipitation of calcium phosphate was insignificant when using seawater, while presence of struvite seeds diminished it further. Among the supersaturation regulators, pH had the most significant effect on the struvite growth with both MgCl2 and seawater, while high N:P molar ratios further improved the struvite crystal growth by seawater. The N:P molar ratios higher than 6 and Mg:P molar ratios higher than 0.2 are recommended to improve the crystal growth kinetics. It was concluded that seawater is a promising alternative magnesium source and the control of supersaturation regulators (i.e., Mg:P, N:P and pH) is an effective strategy to control the reaction kinetics and product properties.
Sina Shaddel; Tonje Grini; Jens-Petter Andreassen; Stein W. Østerhus; Seniz Ucar. Crystallization kinetics and growth of struvite crystals by seawater versus magnesium chloride as magnesium source: towards enhancing sustainability and economics of struvite crystallization. Chemosphere 2020, 256, 126968 .
AMA StyleSina Shaddel, Tonje Grini, Jens-Petter Andreassen, Stein W. Østerhus, Seniz Ucar. Crystallization kinetics and growth of struvite crystals by seawater versus magnesium chloride as magnesium source: towards enhancing sustainability and economics of struvite crystallization. Chemosphere. 2020; 256 ():126968.
Chicago/Turabian StyleSina Shaddel; Tonje Grini; Jens-Petter Andreassen; Stein W. Østerhus; Seniz Ucar. 2020. "Crystallization kinetics and growth of struvite crystals by seawater versus magnesium chloride as magnesium source: towards enhancing sustainability and economics of struvite crystallization." Chemosphere 256, no. : 126968.
Seawater, as an alternative magnesium source, has the potential to improve the overall economics and environmental footprint of struvite production compared to the use of pure magnesium salts. However, the dilution effect and the presence of other ions in seawater can reduce the phosphorus recovery potential and the simultaneous precipitation of other compounds may reduce the quality of the produced struvite. This work presents a comparative study of seawater and MgCl2 by performing a series of thermodynamic equilibrium modeling and crystallization experiments. The results revealed that acceptable phosphorus recovery (80–90%) is achievable by using seawater as the magnesium source for struvite precipitation. Further, the simultaneous precipitation of calcium phosphates was successfully controlled and minimized by optimum selection of reaction pH and seawater volume (i.e. Mg:P and Mg:Ca molar ratios). The increase of temperature from 20 °C to 30 °C reduced the phosphorus recovery by 15–20% while it increased the particle size by 30–35%. The presence of suspended solids in reject water did not have significant effects on phosphorus recovery but it made the struvite separation difficult as the obtained struvite was mixed with suspended solids. The experimental results and economic evaluation showed that the use of seawater can reduce the chemical costs (30–50%) and the CO2-footprint (8–40%) of struvite production. It was concluded that seawater is a potential alternative to pure magnesium sources in struvite production, while studies in larger scale and continuous mode are needed for further verification before full-scale applications.
Sina Shaddel; Tonje Grini; Seniz Ucar; Kamal Azrague; Jens-Petter Andreassen; Stein W. Østerhus. Struvite crystallization by using raw seawater: Improving economics and environmental footprint while maintaining phosphorus recovery and product quality. Water Research 2020, 173, 115572 .
AMA StyleSina Shaddel, Tonje Grini, Seniz Ucar, Kamal Azrague, Jens-Petter Andreassen, Stein W. Østerhus. Struvite crystallization by using raw seawater: Improving economics and environmental footprint while maintaining phosphorus recovery and product quality. Water Research. 2020; 173 ():115572.
Chicago/Turabian StyleSina Shaddel; Tonje Grini; Seniz Ucar; Kamal Azrague; Jens-Petter Andreassen; Stein W. Østerhus. 2020. "Struvite crystallization by using raw seawater: Improving economics and environmental footprint while maintaining phosphorus recovery and product quality." Water Research 173, no. : 115572.
Nutrient recovery from secondary resources, such as wastewater, has received increasing attention in recent years. Nutrient cycle sustainability and recycling approaches are important measures under development and considerations. This paper aims to present an overview of routes and technologies for nutrient recovery from sewage sludge and measures for improving their sustainability. First, current routes for nutrient recovery from sewage sludge are briefly reviewed. Next, an overview of commercial nutrient recovery technologies, projects, and emerging techniques around the world with the key factors for a successful phosphorus recovery technology is presented. Finally, a proposal for improving the sustainability of these practices is presented. It is concluded that the gap between demand and supply can be a major driver for the shift from ‘removal and treat’ to ‘recovery and reuse’. Moreover, there is not, and will never be, a one-size-fits-all solution. Future strategies and roadmaps need to be adapted to the local economy and geographical context more than ever.
Sina Shaddel; Hamidreza Bakhtiary-Davijany; Christian Kabbe; Farbod Dadgar; Stein Østerhus. Sustainable Sewage Sludge Management: From Current Practices to Emerging Nutrient Recovery Technologies. Sustainability 2019, 11, 3435 .
AMA StyleSina Shaddel, Hamidreza Bakhtiary-Davijany, Christian Kabbe, Farbod Dadgar, Stein Østerhus. Sustainable Sewage Sludge Management: From Current Practices to Emerging Nutrient Recovery Technologies. Sustainability. 2019; 11 (12):3435.
Chicago/Turabian StyleSina Shaddel; Hamidreza Bakhtiary-Davijany; Christian Kabbe; Farbod Dadgar; Stein Østerhus. 2019. "Sustainable Sewage Sludge Management: From Current Practices to Emerging Nutrient Recovery Technologies." Sustainability 11, no. 12: 3435.
The enhanced biological phosphorus removal process makes the phosphorus recovery feasible from the dewatering streams of biological sludge. The physicochemical properties of these sidestreams, as an input to a crystallizer, are different before and after anaerobic digestion. In this study, phosphorus recovery by calcium phosphate is proposed for pre-digestion sidestreams and by struvite precipitation for post-digestion sidestreams. The thermodynamic modeling followed by experimental tests was performed to evaluate the recovery efficiency and product properties of struvite and calcium phosphates. The variations in phosphorus recovery potential, reaction kinetics and particle size distribution emphasize the importance of the adjustment of initial supersaturation and pH of the reaction. The optimum pH, considering the economics and recovery efficiency, for both calcium phosphate and struvite precipitation was found to be pH = 8.5, whereas further increase of pH will not improve the overall efficiency of the process. In the case of calcium phosphate precipitation, it was shown that possible phase transformations should be considered and controlled as they affect both process efficiency and product properties. The economic evaluation indicated that the optimized operational condition should be determined for the phosphorus recovery process and that chemical costs for the production of calcium phosphates is lower than for struvite.
Sina Shaddel; Seniz Ucar; Jens-Petter Andreassen; Stein W. Østerhus. Enhancing efficiency and economics of phosphorus recovery process by customizing the product based on sidestream characteristics – an alternative phosphorus recovery strategy. Water Science and Technology 2019, 79, 1777 -1789.
AMA StyleSina Shaddel, Seniz Ucar, Jens-Petter Andreassen, Stein W. Østerhus. Enhancing efficiency and economics of phosphorus recovery process by customizing the product based on sidestream characteristics – an alternative phosphorus recovery strategy. Water Science and Technology. 2019; 79 (9):1777-1789.
Chicago/Turabian StyleSina Shaddel; Seniz Ucar; Jens-Petter Andreassen; Stein W. Østerhus. 2019. "Enhancing efficiency and economics of phosphorus recovery process by customizing the product based on sidestream characteristics – an alternative phosphorus recovery strategy." Water Science and Technology 79, no. 9: 1777-1789.
Struvite crystallization is widely applied for nutrient recovery from wastewater streams. The better understanding of the effects of reaction conditions on final crystal properties will contribute to improve both the recovery efficiency and product quality of struvite as a fertilizer. In this study, batch crystallization experiments were performed in laboratory scale to reveal the effect of supersaturation on the phosphorus recovery and crystal properties. For this purpose, supersaturation is regulated through varying the pH, magnesium and ammonium concentrations in solution. The effects of these parameters on controlling crystal properties such as size and morphology are highlighted through their role as supersaturation regulators. The potential implications of different crystal morphologies on settling velocity and aggregation of crystals are also discussed. This improved understanding could aid in improved struvite crystallization processes for wastewater treatment.
Sina Shaddel; Seniz Ucar; Jens-Petter Andreassen; Stein W. Østerhus. Engineering of struvite crystals by regulating supersaturation – Correlation with phosphorus recovery, crystal morphology and process efficiency. Journal of Environmental Chemical Engineering 2019, 7, 102918 .
AMA StyleSina Shaddel, Seniz Ucar, Jens-Petter Andreassen, Stein W. Østerhus. Engineering of struvite crystals by regulating supersaturation – Correlation with phosphorus recovery, crystal morphology and process efficiency. Journal of Environmental Chemical Engineering. 2019; 7 (1):102918.
Chicago/Turabian StyleSina Shaddel; Seniz Ucar; Jens-Petter Andreassen; Stein W. Østerhus. 2019. "Engineering of struvite crystals by regulating supersaturation – Correlation with phosphorus recovery, crystal morphology and process efficiency." Journal of Environmental Chemical Engineering 7, no. 1: 102918.