hannah stes - Academia.edu (original) (raw)
Papers by hannah stes
Water Science and Technology, 2020
A laboratory-scale sequencing batch reactor was operated for approximately 300 days, divided into... more A laboratory-scale sequencing batch reactor was operated for approximately 300 days, divided into four periods based on the feeding strategy, to develop stable aerobic granular sludge (AGS) while treating chocolate processing wastewater. Application of a prolonged mixed anaerobic feeding was not sufficient to develop AGS and reach stable reactor performance. Through the application of a partially non-mixed and a partially mixed feeding strategy, the reactor performance was increased and stable AGS formation was established characterized by low diluted sludge volume index (D)SVI DSVI10,30) values of 78 ± 27 mL·g−1 and 52 ± 17 mL·g−1, respectively, and a capillary suction time/mixed liquor suspended solids value of 0.9 sec·(g·L−1)−1. The membrane bioreactor (MBR) filtration tests showed a reduction of the fouling rate (FR) and an increase of the sustainable flux (SF0.5) for AGS compared to flocs treating the same industrial wastewater. The SF0.5 (FR > 0.5 mbar·min−1) for the flocs ...
Journal of Water Process Engineering, 2020
This study developed a control system using pH and DO sensors to dynamically control an aerobic g... more This study developed a control system using pH and DO sensors to dynamically control an aerobic granular sludge (AGS) reactor while varying the influent chemical oxygen demand (COD) with a high COD to phosphate ratio (COD/P ratio). The AGS reactor was operated in an anaerobic/aerobic sequence. The pH profile was used to control the anaerobic step and the oxygen uptake rate (OUR) was applied to control the aerobic step. AGS was successfully formed and retained for 220 days. The sludge volume index, SVI5 and SVI30 remained below 50 ml/ g and the average granule size (DV50) increased to approximately 500 μm. The anaerobic and aerobic step durations were effectively controlled guaranteeing (1) an optimal anaerobic COD uptake, which is key to granulation and (2) a good effluent quality.
Water Science and Technology, 2018
A laboratory-scale sequencing batch reactor (SBR) was operated for 450 days to assess aerobic gra... more A laboratory-scale sequencing batch reactor (SBR) was operated for 450 days to assess aerobic granule formation when treating brewery/bottling plant wastewater by consistent application of a feast/famine regime. The experiment was divided into three major periods according to the different operational conditions: (I) no pH control and strong fluctuations in organic loading rate (OLR) (1.18 ± 0.25 kgCOD·(m3·day)−1), (II) pH control and aeration control strategy to reduce OLR fluctuations (1.45 ± 0.65 kgCOD·(m3·day)−1) and (III) no pH control and stable OLR (1.42 ± 0.18 kgCOD·(m3·day)−1). Aerobic granule formation was successful after 80 days and maintained during the subsequent 380 days. The aerobic granular sludge was characterized by SVI5 and SVI30 values below 60 mL.g−1 and dominated by granular, dense structures. An oxygen uptake rate based aeration control strategy insured endogenous respiration at the end of the aerobic phase, resulting in stable SBR operation when the influent...
Bioresource Technology, 2019
Treatment of rapidly varying wastewaters in anaerobic/aerobic 21 aerobic granular sludge (AGS) sy... more Treatment of rapidly varying wastewaters in anaerobic/aerobic 21 aerobic granular sludge (AGS) systems remains problematic. This 22 study investigated AGS formation and the impact of varying COD 23 and phosphorus concentrations on an enhanced biological 24 phosphorus removal (EBPR) AGS SBR with a conductivity based 25 anaerobic and OUR based aerobic dynamically controlled step. 26 Phase 1 investigated the development of AGS. Phase 2 examined 27 the flexibility of the dynamic control strategy and AGS efficiency while 28 rapidly altering the influent composition. AGS was formed 29 successfully in phase 1: the DV50 increased to 285 µm., and the 30 SVI5 and SVI30 decreased to 51 and 40 ml/g respectively. In phase 31 2 the effluent COD and PO4-P concentration remained low at 32 respectively 58 ± 27 mg/L and 0.53 ± 0.77 mg/L. With an anaerobic 33 DOC uptake efficiency of 98.4 ± 0.9 %.
Water Science and Technology, 2019
In this study, the influence of the anaerobic mixed feeding rate on granule stability and reactor... more In this study, the influence of the anaerobic mixed feeding rate on granule stability and reactor performance in a conventional sequencing batch reactor (C-SBR) was investigated while treating various industrial wastewaters. A laboratory-scale SBR fed with malting wastewater rich in phosphorus was operated for approximately 250 days, which was divided into two periods: (I) mixed pulse feed and (II) prolonged mixed feed. Initially, no bio-P activity was observed. However, by lowering the feeding rate biological P-removal was rapidly established and no effect on the aerobic granular sludge (AGS) characteristics was observed. Additionally, to investigate the effect of the mixed feeding rate when treating an industrial effluent with low phosphorus content, i.e. brewery wastewater, a laboratory-scale reactor was operated for approximately 400 days applying different mixed feeding rates. Morphological and molecular analysis indicated that a low substrate concentration promoted the enrichm...
Water Science and Technology
This study investigated the application of a dynamic control strategy in an aerobic granular slud... more This study investigated the application of a dynamic control strategy in an aerobic granular sludge (AGS) reactor treating real variable brewery/bottling wastewater. For 482 days, the anaerobic and aerobic reaction steps in a lab-scale AGS system were controlled dynamically. A pH-based control was used for the anaerobic step, and an oxygen uptake rate (OUR) based control for the aerobic step. Additionally, the effect of an elongated aerobic step, and the effect of the removal of the suspended solids from the influent, on AGS formation were also investigated. In comparison to a static operation, the dynamic operation resulted in similar reactor performance, related to effluent quality and the anaerobic dissolved organic carbon (DOC) uptake efficiency, while the organic loading rate was significantly higher. The removal of suspended solids from the influent by chemical coagulation with FeCl3 turned hybrid floccular-granular sludge into fully granular sludge. The granulation coincided ...
Water Science and Technology, 2020
A laboratory-scale sequencing batch reactor was operated for approximately 300 days, divided into... more A laboratory-scale sequencing batch reactor was operated for approximately 300 days, divided into four periods based on the feeding strategy, to develop stable aerobic granular sludge (AGS) while treating chocolate processing wastewater. Application of a prolonged mixed anaerobic feeding was not sufficient to develop AGS and reach stable reactor performance. Through the application of a partially non-mixed and a partially mixed feeding strategy, the reactor performance was increased and stable AGS formation was established characterized by low diluted sludge volume index (D)SVI DSVI10,30) values of 78 ± 27 mL·g−1 and 52 ± 17 mL·g−1, respectively, and a capillary suction time/mixed liquor suspended solids value of 0.9 sec·(g·L−1)−1. The membrane bioreactor (MBR) filtration tests showed a reduction of the fouling rate (FR) and an increase of the sustainable flux (SF0.5) for AGS compared to flocs treating the same industrial wastewater. The SF0.5 (FR > 0.5 mbar·min−1) for the flocs ...
Journal of Water Process Engineering, 2020
This study developed a control system using pH and DO sensors to dynamically control an aerobic g... more This study developed a control system using pH and DO sensors to dynamically control an aerobic granular sludge (AGS) reactor while varying the influent chemical oxygen demand (COD) with a high COD to phosphate ratio (COD/P ratio). The AGS reactor was operated in an anaerobic/aerobic sequence. The pH profile was used to control the anaerobic step and the oxygen uptake rate (OUR) was applied to control the aerobic step. AGS was successfully formed and retained for 220 days. The sludge volume index, SVI5 and SVI30 remained below 50 ml/ g and the average granule size (DV50) increased to approximately 500 μm. The anaerobic and aerobic step durations were effectively controlled guaranteeing (1) an optimal anaerobic COD uptake, which is key to granulation and (2) a good effluent quality.
Water Science and Technology, 2018
A laboratory-scale sequencing batch reactor (SBR) was operated for 450 days to assess aerobic gra... more A laboratory-scale sequencing batch reactor (SBR) was operated for 450 days to assess aerobic granule formation when treating brewery/bottling plant wastewater by consistent application of a feast/famine regime. The experiment was divided into three major periods according to the different operational conditions: (I) no pH control and strong fluctuations in organic loading rate (OLR) (1.18 ± 0.25 kgCOD·(m3·day)−1), (II) pH control and aeration control strategy to reduce OLR fluctuations (1.45 ± 0.65 kgCOD·(m3·day)−1) and (III) no pH control and stable OLR (1.42 ± 0.18 kgCOD·(m3·day)−1). Aerobic granule formation was successful after 80 days and maintained during the subsequent 380 days. The aerobic granular sludge was characterized by SVI5 and SVI30 values below 60 mL.g−1 and dominated by granular, dense structures. An oxygen uptake rate based aeration control strategy insured endogenous respiration at the end of the aerobic phase, resulting in stable SBR operation when the influent...
Bioresource Technology, 2019
Treatment of rapidly varying wastewaters in anaerobic/aerobic 21 aerobic granular sludge (AGS) sy... more Treatment of rapidly varying wastewaters in anaerobic/aerobic 21 aerobic granular sludge (AGS) systems remains problematic. This 22 study investigated AGS formation and the impact of varying COD 23 and phosphorus concentrations on an enhanced biological 24 phosphorus removal (EBPR) AGS SBR with a conductivity based 25 anaerobic and OUR based aerobic dynamically controlled step. 26 Phase 1 investigated the development of AGS. Phase 2 examined 27 the flexibility of the dynamic control strategy and AGS efficiency while 28 rapidly altering the influent composition. AGS was formed 29 successfully in phase 1: the DV50 increased to 285 µm., and the 30 SVI5 and SVI30 decreased to 51 and 40 ml/g respectively. In phase 31 2 the effluent COD and PO4-P concentration remained low at 32 respectively 58 ± 27 mg/L and 0.53 ± 0.77 mg/L. With an anaerobic 33 DOC uptake efficiency of 98.4 ± 0.9 %.
Water Science and Technology, 2019
In this study, the influence of the anaerobic mixed feeding rate on granule stability and reactor... more In this study, the influence of the anaerobic mixed feeding rate on granule stability and reactor performance in a conventional sequencing batch reactor (C-SBR) was investigated while treating various industrial wastewaters. A laboratory-scale SBR fed with malting wastewater rich in phosphorus was operated for approximately 250 days, which was divided into two periods: (I) mixed pulse feed and (II) prolonged mixed feed. Initially, no bio-P activity was observed. However, by lowering the feeding rate biological P-removal was rapidly established and no effect on the aerobic granular sludge (AGS) characteristics was observed. Additionally, to investigate the effect of the mixed feeding rate when treating an industrial effluent with low phosphorus content, i.e. brewery wastewater, a laboratory-scale reactor was operated for approximately 400 days applying different mixed feeding rates. Morphological and molecular analysis indicated that a low substrate concentration promoted the enrichm...
Water Science and Technology
This study investigated the application of a dynamic control strategy in an aerobic granular slud... more This study investigated the application of a dynamic control strategy in an aerobic granular sludge (AGS) reactor treating real variable brewery/bottling wastewater. For 482 days, the anaerobic and aerobic reaction steps in a lab-scale AGS system were controlled dynamically. A pH-based control was used for the anaerobic step, and an oxygen uptake rate (OUR) based control for the aerobic step. Additionally, the effect of an elongated aerobic step, and the effect of the removal of the suspended solids from the influent, on AGS formation were also investigated. In comparison to a static operation, the dynamic operation resulted in similar reactor performance, related to effluent quality and the anaerobic dissolved organic carbon (DOC) uptake efficiency, while the organic loading rate was significantly higher. The removal of suspended solids from the influent by chemical coagulation with FeCl3 turned hybrid floccular-granular sludge into fully granular sludge. The granulation coincided ...