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Stein W. Østerhus
Department of Hydraulic and Environmental Engineering, Norwegian University of Science and Technology (NTNU), S. P. Andersens vei 5, Trondheim 7491, Norway

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Journal article
Published: 09 July 2020 in Journal of Water Process Engineering
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Enhanced biological phosphorus removal (EBPR) from municipal wastewater has been achieved in a multistage Moving Bed Biofilm Reactor (MBBR) configuration. The process operations can be further optimized by real-time monitoring of water quality parameters in the individual chambers of the EBPR-MBBR process. This work presents a hybrid, soft-sensor as a cost-effective monitoring option for real-time estimation of phosphates (PO43−-P) and soluble COD (sCOD) concentrations in the anaerobic chambers of a multistage EBPR-MBBR pilot plant. The soft-sensor is developed by implementing an Extended Kalman filter on a reduced-order nutrient removal model. The hybrid model is constructed by combining mechanistic elements of phosphorus release kinetics in anaerobic conditions, and a statistical model correlating PO43−-P and sCOD concentration with conductivity measurements. A systematic method for developing, calibrating a reduced-order model and tuning of the Kalman filter parameters have been discussed in this work. The drift in soft-sensor performance was studied and practical solutions were suggested for re-calibrating the model utilizing data from periodic lab measurements. The estimation results are successfully validated against standardized lab measurements to demonstrate the accuracy of the soft-sensing algorithm.

ACS Style

Abhilash M. Nair; Blanca M. Gonzalez-Silva; Finn Aakre Haugen; Harsha Ratnaweera; Stein W. Østerhus. Real-time monitoring of enhanced biological phosphorus removal in a multistage EBPR-MBBR using a soft-sensor for phosphates. Journal of Water Process Engineering 2020, 37, 101494 .

AMA Style

Abhilash M. Nair, Blanca M. Gonzalez-Silva, Finn Aakre Haugen, Harsha Ratnaweera, Stein W. Østerhus. Real-time monitoring of enhanced biological phosphorus removal in a multistage EBPR-MBBR using a soft-sensor for phosphates. Journal of Water Process Engineering. 2020; 37 ():101494.

Chicago/Turabian Style

Abhilash M. Nair; Blanca M. Gonzalez-Silva; Finn Aakre Haugen; Harsha Ratnaweera; Stein W. Østerhus. 2020. "Real-time monitoring of enhanced biological phosphorus removal in a multistage EBPR-MBBR using a soft-sensor for phosphates." Journal of Water Process Engineering 37, no. : 101494.

Journal article
Published: 21 June 2019 in Sustainability
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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.

ACS Style

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 Style

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 (12):3435.

Chicago/Turabian Style

Sina 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.

Review
Published: 30 May 2019 in Journal of Membrane Science
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Membrane cleaning is crucial to maintain the permeability and selectivity of membranes. Physical cleaning can mitigate membrane fouling, lower the frequency of chemical cleaning, thus prolong membrane lifetime, and reduce operational costs. Backpulsing is a promising physical cleaning method, which can effectively mitigate external and non-adhesive fouling and has been used in many industrial fields. However, a comprehensive understanding of backpulsing and the optimization of this technology is still lacking. This paper critically reviews the development of backpulsing technique in microfiltration (MF) and ultrafiltration (UF) processes. Firstly, the fundamentals of backpulsing are addressed. Secondly, applications of backpulsing are summarized according to the applied fields. Results of pilot- and commercial-scale operations are presented. Moreover, factors influencing backpulsing efficiency are illustrated, including feed properties, membrane properties and operating parameters. Furthermore, mathematical models of backpulsing are overviewed. The models not only predict membrane productivity, but also provide a perspective to evaluate the performance of backpulsing in fouling mitigation. Finally, the existing challenges and future outlook are discussed.

ACS Style

Yinghong Gao; Jie Qin; Zhiwei Wang; Stein W. Østerhus. Backpulsing technology applied in MF and UF processes for membrane fouling mitigation: A review. Journal of Membrane Science 2019, 587, 117136 .

AMA Style

Yinghong Gao, Jie Qin, Zhiwei Wang, Stein W. Østerhus. Backpulsing technology applied in MF and UF processes for membrane fouling mitigation: A review. Journal of Membrane Science. 2019; 587 ():117136.

Chicago/Turabian Style

Yinghong Gao; Jie Qin; Zhiwei Wang; Stein W. Østerhus. 2019. "Backpulsing technology applied in MF and UF processes for membrane fouling mitigation: A review." Journal of Membrane Science 587, no. : 117136.

Journal article
Published: 01 December 2009 in Water Supply
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This paper presents the use of a V-UV/UV/TiO2 reactor (M300 water purifier®) for the removal of sulfamethoxazole and atrazine from natural water. The efficiency of the different processes (photolysis, Vacuum UV (V-UV) and photocatalysis) within the photoreactor was investigated using para-chlorobenzoic acid (pCBA) which is a good probe for hydroxyl radicals. The effect of pH, dissolved organic carbon (DOC) and total inorganic carbon (TIC) was also studied. V-UV was found to be the most efficient process for pCBA degradation within this unit. No photocatalytic degradation was observed. The water quality largely affected the efficiency of the system. Indeed, both DOC and TIC lowered the hydroxyl radical concentration in the system, but DOC did it to a larger extent. Atrazine and sulfamethoxazole, were successfully degraded, and as for pCBA, V-UV was the most efficient process. Sulfamethoxazole displayed a better removal by photocatalysis than atrazine and pCBA. In addition, there was a larger contribution of photolysis during the degradation of sulfamethoxazole than of atrazine. The UV254 nm absorbance of the water affected the photolysis of sulfamethoxazole which has a high molar extinction coefficient and quantum yield at 254 nm, while the DOC is mainly competing with the pollutants for the hydroxyl radicals.

ACS Style

Kamal Azrague; S. W. Osterhus. Persistent organic pollutants (POPs) degradation in natural waters using a V-UV/UV/TiO2 reactor. Water Supply 2009, 9, 653 -660.

AMA Style

Kamal Azrague, S. W. Osterhus. Persistent organic pollutants (POPs) degradation in natural waters using a V-UV/UV/TiO2 reactor. Water Supply. 2009; 9 (6):653-660.

Chicago/Turabian Style

Kamal Azrague; S. W. Osterhus. 2009. "Persistent organic pollutants (POPs) degradation in natural waters using a V-UV/UV/TiO2 reactor." Water Supply 9, no. 6: 653-660.

Journal article
Published: 01 March 2009 in Water Science and Technology
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The catalytic effect of commercially available ceramic Raschig rings versus stainless steel rings (known to be oxidant resistant) at different water qualities, for the decomposition of ozone and the hydroxyl radical formation have been investigated by using an ozone bubble column. Para-chlorobenzoic acid (pCBA) has been used as a model pollutant since it has been reported to be an ideal compound for ozone AOP studies because it displays slow reaction rates with ozone, but rapid oxidation kinetics with the OH radical. While the ozone was quite stable when the stainless steel rings were used as a packing media, the ceramic media enhanced the decomposition of the ozone. Nevertheless, the water quality was found to significantly affect the ozone stability. Indeed, in addition to high pH, both NOM and TIC lowered the ozone concentration in the system. When considering the degradation of pCBA, the ceramic packing rings, as high pH and NOM, increases its rate constant which is correlated to the higher decomposition of ozone and consequently to higher formation of hydroxyl radicals. In contrast, TIC decreased the degradation rate of pCBA even if it decomposes the ozone which is due to its scavenging effect.

ACS Style

Kamal Azrague; S. W. Osterhus; J. G. Biomorgi. Degradation of pCBA by catalytic ozonation in natural water. Water Science and Technology 2009, 59, 1209 -1217.

AMA Style

Kamal Azrague, S. W. Osterhus, J. G. Biomorgi. Degradation of pCBA by catalytic ozonation in natural water. Water Science and Technology. 2009; 59 (6):1209-1217.

Chicago/Turabian Style

Kamal Azrague; S. W. Osterhus; J. G. Biomorgi. 2009. "Degradation of pCBA by catalytic ozonation in natural water." Water Science and Technology 59, no. 6: 1209-1217.