High-rate activated sludge systems combined with dissolved air flotation enable effective organics removal and recovery

Cagnetta, Cristina; Saerens, Bart; Meerburg, Francis; Decru, Stijn O.; Broeders, E.; Menkveld, W; Vandekerckhove, Tom; Vrieze, Jo De; Vlaeminck, Siegfried E.; Verliefde, Arne; Gusseme, Bart De; Weemaes, Marjoleine; Rabaey, Korneel

doi:10.1016/j.biortech.2019.121833

Cited by 44 publications

(20 citation statements)

References 31 publications

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“…The NH 4 + /NO 2 – ratio (∼1.3) in the effluent is suitable for subsequent anammox, although pH adjustment may be required (e.g., via adding raw wastewater or chemicals) prior to feeding anammox reactors. Note that ∼50 mg Fe/L was dosed into raw domestic wastewater to reduce alkalinity in the present study, and this dosage is within a typical range (20–60 mg Fe/L) used in the common CEPT process. − As the dosed-Fe (>98%) mainly precipitated during CEPT, the measured iron concentration in the effluent of the MBBR was <2 mg Fe/L. In sum, the results of this study add a new option to the technological toolkit for controlling NOB growth for domestic-strength wastewater treatment.…”

Section: Resultsmentioning

confidence: 61%

Determining Factors for Nitrite Accumulation in an Acidic Nitrifying System: Influent Ammonium Concentration, Operational pH, and Ammonia-Oxidizing Community

Meng

Wang

et al. 2022

Environ. Sci. Technol.

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Acidic nitrification is attracting wide attention because it can enable robust suppression of nitrite-oxidizing bacteria (NOB) in wastewater treatment. This study reports a comprehensive assessment of the novel acidic nitrification process to identify the key factors that govern stable nitrite accumulation. A laboratory-scale moving-bed biofilm reactor receiving low-alkalinity wastewater was continuously operated under acidic conditions (pH < 6) for around two years, including nine stages varying influent and operational conditions. The results revealed that nitrite accumulation was related to three factors, i.e., influent ammonium concentration, operating pH, and ammonia-oxidizing microbial community. These three factors impact nitrite accumulation by altering the in situ concentration of free nitrous acid (FNA), which is a potent inhibitor of NOB. The critical FNA concentration is approximately one part per million (ppm, ∼1 mg HNO2-N/L), above which nitrite accumulation is stably maintained in an acidic nitrifying system. The findings of this study suggest that stable nitrite accumulation via acidic ammonia oxidation can be maintained under a range of influent and operational conditions, as long as a ppm-level of FNA is established. Taking low-strength mainstream wastewater (40–50 mg NH4 +-N/L) with limited alkalinity as an example, stable nitrite accumulation was experimentally demonstrated at a pH of 4.35, under which an in situ FNA of 2.3 ± 0.6 mg HNO2-N/L was attained. Under these conditions, Candidatus Nitrosoglobus became the only ammonia oxidizer detectable by 16S rRNA gene sequencing. The results of this study deepen our understanding of acidic nitrifying systems, informing further development of novel wastewater treatment technologies.

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Section: Resultsmentioning

confidence: 61%

Determining Factors for Nitrite Accumulation in an Acidic Nitrifying System: Influent Ammonium Concentration, Operational pH, and Ammonia-Oxidizing Community

Meng

Wang

et al. 2022

Environ. Sci. Technol.

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“…This method is widely used for municipal and industrial wastewater treatment purposes, such as sludge thickening, purification of algae-rich water, separating oil from water, treatment of refineries and poultry slaughterhouse wastewater, etc (12,13). In a study conducted by Cagnetta et al, DAF combined or coupled with a high-rate activated sludge and showed a good performance for the removal of total suspended solids (TSS) and chemical oxygen demand (COD) (14). In DAF systems, compressed air is injected into the sewage tank.…”

Section: Introductionmentioning

confidence: 99%

Effect of coagulation and sonication on the dissolved air flotation (DAF) process for thickening of biological sludge in wastewater treatment

Atamaleki

Miranzadeh

Mostafaii

et al. 2020

Environ Health Eng Manag

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Background: Dissolved air floatation (DAF) is one of the methods has been used for the sludge thickening in wastewater treatment plants. This study aimed to investigate the effects of coagulation and sonication processes as additional configurations on the efficiency of a lab-scale DAF process for thickening of the biological sludge of an industrial wastewater treatment plant in Kashan, Iran. Methods: The required amounts of sludge samples were collected from a wastewater treatment plant and kept at temperature of 4°C. Variables, such as pressure (3, 5, and 7 atm), flotation time (5 and 10 minutes), ultrasonic irradiation power (0, 75, and 150 W), and presence/absence of Fe-based coagulant were considered on a sequencing batch reactor (SBR) included coagulation, flotation, and sonication processes, respectively. Results: The use of ultrasonic waves led to an insignificant increase in the DAF efficiency (P > 0.05), however, the application of coagulant significantly increased the thickening efficiency (P < 0.05). The maximum efficiency of the process was achieved at flotation time of 5 min, pressure of 3 atm, and sonication power of 75 W. Conclusion: According to the results, DAF has a proper efficiency for thickening of biological sludge. Coagulation compared to sonication has a greater effect on the efficiency of the process.

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“…Ahora bien, el espesamiento por flotación de aire disuelto o DAF (Dissolved Air Flotation) basado en saturar con aire el agua, generando burbujas que atrapan las partículas del lodo para ser separadas de la fase líquida, presenta mayor eficiencia de separación entre los sólidos y líquidos que el espesamiento por gravedad, aunque tiene elevado costo y complejo mantenimiento. Dicho tratamiento, acoplado con el sistema de lodos activados de alta tasa, elimina el 78 % de los sólidos suspendidos totales influyentes [11]. No obstante,el espesamiento por flotación de aire disuelto presenta un alto consumo energético y a diferencia del espesamiento por centrifugación, el tratamiento por DAF puede verse limitado por la generación de olores.…”

Section: Alternativas De Espesamiento De Lodosunclassified

Alternativas para tratar lodos originados en sistemas de tratamiento de aguas residuales: una revisión

Torrado

Perez²

2022

Ing.

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Contexto: La investigación han demostrado la eficiencia de diversos tratamientos para lodos. Sin embargo, se han presentado nuevas alternativas que ameritan una revisión actualizada. Es por ello que este trabajo tiene como objetivo realizar dicha actualización con respecto a técnicas convencionales y nuevas para tratar los lodos. Método: Este artículo está basado en una revisión de documentos en diversas bases de datos, agrupando en primera instancia las alternativas convencionales y posteriormente las nuevas, constituidas ambas por alternativas de técnicas de espesamiento, estabilización y deshidratación de lodos, y analizándolas con base en criterios económicos, técnicos y ambientales. Resultados: En este estudio se encontró que la ósmosis directa es una de las alternativas más prometedoras en el espesamiento de lodos, la oxidación de agua supercrítica y la pirólisis en la estabilización y la filtración al vacío en la deshidratación de dichos subproductos. Conclusiones: Este artículo permitió la revisión actualizada de alternativas convencionales y nuevas para el tratamiento de lodos, observando que, tanto en el espesamiento como en la estabilización, las nuevas alternativas tienen eficiencias altas, mientras la filtración al vacío, una alternativa convencional, mejoró su rendimiento mediante el uso del floculante modificado, destacándose en la deshidratación de lodos. Es por ello que se requieren más investigaciones que mejoren los desafíos y rendimientos presentes e indaguen sobre la liberación al ambiente de contaminantes al utilizar los biosólidos.

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High-rate activated sludge systems combined with dissolved air flotation enable effective organics removal and recovery

Cited by 44 publications

References 31 publications

Determining Factors for Nitrite Accumulation in an Acidic Nitrifying System: Influent Ammonium Concentration, Operational pH, and Ammonia-Oxidizing Community

Determining Factors for Nitrite Accumulation in an Acidic Nitrifying System: Influent Ammonium Concentration, Operational pH, and Ammonia-Oxidizing Community

Effect of coagulation and sonication on the dissolved air flotation (DAF) process for thickening of biological sludge in wastewater treatment

Alternativas para tratar lodos originados en sistemas de tratamiento de aguas residuales: una revisión

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