Pilot-scale magnetic recovery of vivianite from digested sewage sludge

Wijdeveld, W.K.; Prot, T.; Sudintas, G.; Kuntke, Philipp; Korving, Leon; Loosdrecht, Mark C.M. van

doi:10.1016/j.watres.2022.118131

Cited by 53 publications

(24 citation statements)

References 23 publications

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“…Both thermal hydrolysis (Exelys) and Al dosing resulted in poorly crystalline vivianite (PXRD amorphous). This may impede P recovery since magnetic separation is less efficient for nanocrystalline vivianite . Vivianite-P can account for 70–90% of TP if Fe dosing was increased to achieve molar Fe:P of 2.5 in the sludge, and vivianite-P in digested sludge increased from 20 to 50% of TP after Fe dosing was doubled (molar Fe:P from 0.46 to 0.85) based on Mössbauer .…”

Section: Environmental Implicationsmentioning

confidence: 99%

“…This may impede P recovery since magnetic separation is less efficient for nanocrystalline vivianite. 11 Vivianite-P can account for 70−90% of TP if Fe dosing was increased to achieve molar Fe:P of 2.5 in the sludge, 17 and vivianite-P in digested sludge increased from 20 to 50% of TP after Fe dosing was doubled (molar Fe:P from 0.46 to 0.85) based on Mossbauer. 10 Hence, there is a potential to improve the vivianite production by intensified Fe dosing at Ejby Mølle and Billund, as their molar Fe:P in the digested sludge was only 0.63−0.65 (vivianite-P accounted for 32−39% of TP).…”

Section: Environmental Implicationsmentioning

confidence: 99%

“…Conventionally, P is recycled by direct application on farmland of the P-rich sewage sludge (2–3 wt % P) . However, the use has been banned or limited in some European countries due to concerns about pollutants, e.g., pharmaceuticals, heavy metals, and pathogens. , This has spurred the development of alternative, more advanced P recovery technologies to harvest P as value-added products, including struvite precipitation, increased Fe dosing for enhanced vivianite formation followed by magnetic separation, − formation of P-rich biochar by (hydro)thermal treatment of sludge, , metal phosphate precipitation after acidic leaching of P from sludge, , and P extraction after sludge incineration . Selection of the most efficient P recovery technology and where at the WWTP to implement it require detailed insight into the chemical P speciation in the sludge throughout the WWTP .…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Variation in Phosphorus Speciation of Sewage Sludge throughout Three Wastewater Treatment Plants: Determined by Sequential Extraction Combined with Microscopy, NMR Spectroscopy, and Powder X-ray Diffraction

Wang

Raju

Almind-Jørgensen³

et al. 2022

Environ. Sci. Technol.

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The variation in phosphorus (P) speciation of sewage sludge throughout three wastewater treatment plants (WWTPs) was obtained by combining sequential P extraction with optical and scanning electron microscopy (SEM), chemical analyses, powder X-ray diffraction (PXRD), and 27Al and 31P nuclear magnetic resonance (NMR) spectroscopy. The WWTPs combine chemical P removal (CPR) and enhanced biological P removal (EBPR) and were compared to understand the effect of iron (Fe) dosing with and without codosing of aluminum (Al) and thermal hydrolysis on the P speciation. 31P NMR showed comparable inorganic orthophosphate (ortho-P, 53–60% of total P) and organophosphate (organic-P, 37–45%) in primary sludge, whereas polyphosphate (poly-P, 23–44%) from poly-P accumulating organisms (PAOs) was mainly observed in the secondary sludge. Inorganic ortho-P (90–98%) dominated after anaerobic digestion, which degraded poly-P and most organic-P. The inorganic ortho-P was mainly Fe bound P (Fe-P), especially after anaerobic digestion (71%). Codosing of Fe and Al led to two comparable fractions: Fe-P (38%) and P sorbed on amorphous Al (hydr)oxides (38%). Vivianite was identified in all samples by microscopy and chemical extraction but was PXRD amorphous in 12 out of 17 samples. Thus, vivianite may be more common in sewage sludge than previously known.

show abstract

Section: Environmental Implicationsmentioning

confidence: 99%

Section: Environmental Implicationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Variation in Phosphorus Speciation of Sewage Sludge throughout Three Wastewater Treatment Plants: Determined by Sequential Extraction Combined with Microscopy, NMR Spectroscopy, and Powder X-ray Diffraction

Wang

Raju

Almind-Jørgensen³

et al. 2022

Environ. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…Most P recovery processes rely on precipitation or crystallization to recover the P element, for example, struvite, 9 hydroxyapatite, 10 or vivianite. 11 The additional amount of metal salt is one of the key problems affecting the precipitation reaction. However, excessive metal ions are added to water, resulting in poor P recovery and an increase in cost.…”

Section: Introductionmentioning

confidence: 99%

Machine Learning Facilitates the Application of Electrochemically Induced Precipitation for the Removal of Phosphorous

Hao

Zhang

et al. 2023

ACS EST Water

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Electrochemically induced precipitation methods for phosphorous removal and recovery have received increasing attention, which have the advantage of achieving phosphorous recovery without the use of additional chemicals. In this work, a novel integrated electrochemical fixed bed packed with magnetite (EPM) for the removal of phosphorous was designed and constructed. To achieve control automatically, machine learning technology was utilized in this study. Accurately predicting the phosphorous removal efficiency and cost is the goal for model training and development. The artificial neural network (ANN), random forest (RF), and multiple linear regression (MLR) models were implemented using the experimental data of EPM. The MLR model showed poor prediction accuracy, indicating that the linear model is insufficient to describe the EPM process. ANN and RF achieved an acceptable accuracy in predicting phosphorous removal and cost, which were optimized using a grid-searching method and deeply analyzed by variable importance to identify the importance of variables. According to the machine learning model, the current, feed rate, and Ca 2+ concentration have a significant role in the efficiency and cost of phosphorous removal. Future research should focus on data collection for electrochemical systems in actual operations, as well as designing and optimizing machine learning models suitable to electrochemical systems on automation.

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“…Meanwhile, the filterability of the digested sludge was also improved, resulting in good sludge dewaterability and, thus, reduced sludge disposal costs . Moreover, the potential recovery of the valuable resource phosphorus in the form of vivianite is believed to be a promising method as it can be easily achieved by using a magnetic separator . Then, 70–90% of the phosphorus in the digested sludge might be recovered as vivianite as long as enough iron is provided .…”

mentioning

confidence: 99%

Re-evaluating the Necessity of High-Rate Activated Sludge Processes for Mainstream Anammox

Cao

Koch

Drewes

et al. 2023

Environ. Sci. Technol.

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Pilot-scale magnetic recovery of vivianite from digested sewage sludge

Cited by 53 publications

References 23 publications

Variation in Phosphorus Speciation of Sewage Sludge throughout Three Wastewater Treatment Plants: Determined by Sequential Extraction Combined with Microscopy, NMR Spectroscopy, and Powder X-ray Diffraction

Variation in Phosphorus Speciation of Sewage Sludge throughout Three Wastewater Treatment Plants: Determined by Sequential Extraction Combined with Microscopy, NMR Spectroscopy, and Powder X-ray Diffraction

Machine Learning Facilitates the Application of Electrochemically Induced Precipitation for the Removal of Phosphorous

Re-evaluating the Necessity of High-Rate Activated Sludge Processes for Mainstream Anammox

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