Surface water treatment by UV/H<sub>2</sub>O<sub>2</sub>with subsequent soil aquifer treatment: impact on micropollutants, dissolved organic matter and biological activity

Wünsch, Robin; Plattner, Julia; Cayon, David; Eugster, Fabienne; Gebhardt, Jens; Wülser, Richard; Gunten, Urs von; Wintgens, Thomas

doi:10.1039/c9ew00547a

Cited by 8 publications

(4 citation statements)

References 95 publications

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“…With respect to BTR, previous studies' results are equivocal and site-specific. Filter et al (2017) and Wünsch et al (2019) reported poor BTR removal (< 30 %) during column experiments with sediment cores from the Saatwinkel SAT site in Germany and soil from the Lange Erlen site in Switzerland, respectively. On the other hand, Glorian et al (2018) reported 77 %-98 % BTR removal at bank filtration sites in northern India.…”

Section: Effluent Qualitymentioning

confidence: 99%

Improving soil aquifer treatment efficiency using air injection into the subsurface

Arad

Ziner

Moshe

et al. 2023

Hydrol. Earth Syst. Sci.

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Abstract. Soil aquifer treatment (SAT) is an effective and sustainable technology for wastewater or stormwater treatment, storage, and reuse. During SAT, the vadose zone acts as a pseudo-reactor in which physical and biochemical processes are utilized to improve the infiltrated-water quality. Dissolved oxygen (DO) is necessary for aerobic microbial oxidation of carbon and nitrogen species in the effluent. Therefore, to enhance aeration, SAT is generally operated in flooding and drying cycles. While long drying periods (DPs) lead to better oxidizing conditions and improve water quality, they reduce recharge volumes. As the population grows, the quantity of effluent directed to SAT sites increases, and increasing recharge volumes become a concern and often a limiting factor for SAT usage. In this study, direct subsurface air injection SAT (Air-SAT) was tested as an alternative to long-DP operation. Six long-column experiments were conducted (2 m column) that aimed to examine the effect of air injection on the soil's water content, oxidation–reduction potential (ORP), DO concentrations, infiltrated amounts, and ultimate outflow quality. In addition to basic parameters, such as dissolved organic C (DOC) and N species, the effluent quality analysis also included an examination of three emerging water contaminants: ibuprofen, carbamazepine, and 1H-benzotriazole. Pulsed-air-injection experiments were conducted during continuous flooding using different operation modes (i.e., air pulse durations, frequencies, and airflow rates). Our results show that Air-SAT operation doubled the time during which infiltration was possible (i.e., the infiltration was continuous with no downtime) and allowed up to a 46 % higher mean infiltration rate in some cases. As a result, the infiltration volumes in the Air-SAT modes were 47 %–203 % higher than conventional flooding–drying operation (FDO). A longer air pulse duration (60 min vs. 8 min) and higher airflow rate (∼2 L min−1 vs. ∼1 L min−1) led to a higher mean infiltration rate, whereas a high pulse frequency (4.5 h−1) led to a lower mean infiltration rate compared with low-frequency operation (24 h−1). Air injection also allowed good recovery of the ORP and DO levels in the soil, especially in the high-frequency Air-SAT experiments, where steady aerobic conditions were maintained during most of the flooding. Consequently, the mean DOC, total Kjeldahl N (TKN), and ibuprofen removal values in these experiments were up to 9 %, 40 %, and 65 % higher than those with FDO, respectively. However, high-frequency Air-SAT during continuous flooding also led to significant deterioration of the mean infiltration rate, probably due to enhanced biological clogging. Hence, it may be more feasible and beneficial to combine it with conventional FDO, allowing a steady infiltration rate and increased recharge volumes while sustaining high effluent quality. While these results still need to be verified at full scale, they highlight the possibility of using air injection to minimize the DP length and alleviate the pressure on existing SAT sites.

show abstract

Section: Effluent Qualitymentioning

confidence: 99%

Improving soil aquifer treatment efficiency using air injection into the subsurface

Arad

Ziner

Moshe

et al. 2023

Hydrol. Earth Syst. Sci.

View full text Add to dashboard Cite

show abstract

“…With respect to BTR, previous studies' results are equivocal and site-specific. Filter et al (2017) and Wünsch et al (2019) reported poor BTR removal (<30%) during column experiments with sediment cores from the Saatwinkel SAT site in Germany and soil from the Lange Erlen site in Switzerland, respectively. On the other hand, Glorian et al (2018) reported 77-98% of BTR removal in bank filtration sites in Northern India.…”

Section: Effluent Qualitymentioning

confidence: 99%

Improving soil aquifer treatment efficiency using air injection into the subsurface

Arad

Ziner

Moshe

et al. 2022

Preprint

View full text Add to dashboard Cite

Abstract. Soil aquifer treatment (SAT) is an effective and sustainable technology for wastewater or stormwater treatment, storage and reuse. During SAT, the vadose zone acts as a pseudo reactor in which physical and biochemical processes are utilized to improve the infiltrated water quality. Dissolved oxygen (DO) is necessary for aerobic microbial oxidation of carbon and nitrogen species in the effluent. Therefore, to enhance aeration, SAT is generally operated in flooding and drying cycles. While long drying periods (DPs) lead to better oxidizing conditions and improve water quality, they reduce recharge volumes. As the population grows, the quantity of effluent directed to SAT sites increases and increasing recharge volumes become a concern and often a limiting factor for SAT usage. In this study, direct subsurface air injection SAT (Air-SAT) was tested as an alternative to long DPs operation. Six long column experiments were conducted, aiming to examine the effect of air injection on the soil's water content, oxidation-reduction potential (ORP), DO concentrations, infiltrated amounts and ultimate outflow quality. In addition to basic parameters such as dissolved organic-C (DOC) and N species, the effluent quality analysis also included an examination of three emerging water contaminants – Ibuprofen, Carbamazepine and 1H-benzotriazole. Pulsed air injection experiments were conducted during continuous flooding at different operation modes (i.e., air pulse durations, frequencies and airflow rates). Our results show that the Air-SAT operation doubled the infiltration time (i.e., the infiltration was continuous with no off-time) and allowed up to 46 % higher infiltration rate in some cases. As a result, the infiltrated volumes in the Air-SAT modes were 47–203 % higher than the conventional flooding-drying operation (FDO). Longer air pulse duration (60 vs. 8 min) and higher airflow rate (~2 vs. ~1 SLPM) led to a higher infiltration rate, while a high pulse frequency (4.5−1 h−1) led to a lower infiltration rate compared to low-frequency operation (24−1 h−1). The air injection also allowed good recovery of the ORP and DO levels in the soil, especially in the high-frequency Air-SAT experiments, where steady aerobic conditions were maintained during most of the flooding. Consequently, the mean DOC, total Kjeldahl N (TKN), and Ibuprofen removals in these experiments were higher than in FDO by up to 9, 40, and 65 %, respectively. However, high-frequency Air-SAT during continuous flooding also led to significant deterioration in the infiltration rate, probably due to enhanced biological clogging. Hence, it may be more feasible and beneficial to combine it with the conventional FDO, allowing a steady infiltration rate and increased recharge volumes, while sustaining high effluent quality. While those results still need to be verified at full scale, they open the possibility of using air injection to minimize the DPs length and alleviate the pressure over existing SAT sites.

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“…Current water depollution technologies (filtration membranes, reverse osmosis, adsorption, coagulation, deep UV with H 2 O 2 , etc.) have high operating costs and consume a lot of energy [2][3][4][5]. Consequently, the development of green and energy-efficient depollution technologies is attracting much attention.…”

Section: Introductionmentioning

confidence: 99%

Tuneable Functionalization of Glass Fibre Membranes with ZnO/SnO2 Heterostructures for Photocatalytic Water Treatment: Effect of SnO2 Coverage Rate on the Photocatalytic Degradation of Organics

et al. 2020

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The construction of a ZnO/SnO2 heterostructure is considered in the literature as an efficient strategy to improve photocatalytic properties of ZnO due to an electron/hole delocalisation process. This study is dedicated to an investigation of the photocatalytic performance of ZnO/SnO2 heterostructures directly synthesized in macroporous glass fibres membranes. Hydrothermal ZnO nanorods have been functionalized with SnO2 using an atomic layer deposition (ALD) process. The coverage rate of SnO2 on ZnO nanorods was precisely tailored by controlling the number of ALD cycles. We highlight here the tight control of the photocatalytic properties of the ZnO/SnO2 structure according to the coverage rate of SnO2 on the ZnO nanorods. We show that the highest degradation of methylene blue is obtained when a 40% coverage rate of SnO2 is reached. Interestingly, we also demonstrate that a higher coverage rate leads to a full passivation of the photocatalyst. In addition, we highlight that 40% coverage rate of SnO2 onto ZnO is sufficient for getting a protective layer, leading to a more stable photocatalyst in reuse.

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Surface water treatment by UV/H₂O₂with subsequent soil aquifer treatment: impact on micropollutants, dissolved organic matter and biological activity

Abstract: UV/H2O2 treatment of sand-filtered surface water before soil aquifer treatment increases the total removal of organic micropollutants and has an impact on microbial activity without pronounced effects on dissolved organic matter removal.

Cited by 8 publications

References 95 publications

Improving soil aquifer treatment efficiency using air injection into the subsurface

Improving soil aquifer treatment efficiency using air injection into the subsurface

Improving soil aquifer treatment efficiency using air injection into the subsurface

Tuneable Functionalization of Glass Fibre Membranes with ZnO/SnO2 Heterostructures for Photocatalytic Water Treatment: Effect of SnO2 Coverage Rate on the Photocatalytic Degradation of Organics

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Surface water treatment by UV/H2O2with subsequent soil aquifer treatment: impact on micropollutants, dissolved organic matter and biological activity

Abstract: UV/H2O2 treatment of sand-filtered surface water before soil aquifer treatment increases the total removal of organic micropollutants and has an impact on microbial activity without pronounced effects on dissolved organic matter removal.

Cited by 8 publications

References 95 publications

Improving soil aquifer treatment efficiency using air injection into the subsurface

Improving soil aquifer treatment efficiency using air injection into the subsurface

Improving soil aquifer treatment efficiency using air injection into the subsurface

Tuneable Functionalization of Glass Fibre Membranes with ZnO/SnO2 Heterostructures for Photocatalytic Water Treatment: Effect of SnO2 Coverage Rate on the Photocatalytic Degradation of Organics

Contact Info

Product

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Surface water treatment by UV/H₂O₂with subsequent soil aquifer treatment: impact on micropollutants, dissolved organic matter and biological activity