Impacts of Accumulated Particulate Organic Matter on Oxygen Consumption and Organic Micro-Pollutant Elimination in Bank Filtration and Soil Aquifer Treatment

The process of bank filtration acts as a barrier against many anthropogenic micropollutants, such as pharmaceuticals and industrial products, leading to a substantial improvement of groundwater quality. The performance of this barrier is, however, affected by seasonal influences and subject to significant temporal changes, which have already been described in the literature. Much less is known about spatial differences when considering one field site. In order to investigate this issue, two undisturbed cores from a well-investigated bank filtration field site were sampled and operated in the course of a column study. The ultimate aim was the identification and quantification of heterogeneities with regard to the biodegradation of 14 wastewater derived micropollutants, amongst others acesulfame, gabapentin, metoprolol, oxypurinol, candesartan, and olmesartan. While six of the compounds entirely persisted, eight compounds were prone to degradation. For those compounds that were subject to degradation, degradation rate constants ranged between 0.2 day−1 (gabapentin) and 31 day−1 (valsartan acid). Further, the rate constants consistently diverged between the distinct cores. In case of the gabapentin metabolite gabapentin-lactam, observed removal rate constants differed by a factor of six between the cores. Experimental data were compared to values calculated according to two structure based prediction models.

Section: Reactive Compoundsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Trace Organic Removal during River Bank Filtration for Two Types of Sediment

Burke

Schneider

Greskowiak

et al. 2018

“…High temperatures promote biological reaction (denitrification) rates and the rate of oxygen consumption [47]. Oxygen depletion through microbial activity, coupled with decreased oxygen solubility in warmer water, led to reductive conditions that were favorable to denitrification in the RBF system during the summer [20,47]. Higher temperatures and corresponding reductive conditions resulted in greater NO 3 -N removal during the summer than during the winter in the groundwater environment.…”

Section: Temporal Variations Of Nitrogen and Cod In Groundwatermentioning

confidence: 99%

“…The processes of RBF that improve water quality are influenced by several factors such as temperature, redox conditions, the characteristics of the saturated zone, river water quality [19][20][21] and different hydrogeological conditions [22,23]. For example, seasonal changes in river flow and temperature can result in rapid changes between aerobic and anoxic conditions.…”

Section: Introductionmentioning

confidence: 99%

Nitrogen and Organics Removal during Riverbank Filtration along a Reclaimed Water Restored River in Beijing, China

Pan

Huang

2018

Reclaimed water has been widely used to restore rivers and lakes in water scarce areas as well as in Beijing municipality, China. However, refilling the rivers with reclaimed water may result in groundwater pollution. A three-year field monitoring program was conducted to assess the effect of a riverbank filtration (RBF) system on the removal of nitrogen and organics from the Qingyang River of Beijing, which is replenished with reclaimed water. Water samples from the river, sediment, and groundwater were collected for NO 3-N, NH 4-N, and chemical oxygen demand (COD) was measured. The results indicate that about 85% of NO 3-N was removed from the riverbed sediments. Approximate 92% of NH 4-N was removed during the infiltration of water from river to aquifer. On average, 54% of COD was removed by RBF. The attenuation of NO 3-N through RBF to the groundwater varied among seasons and was strongly related to water temperature. On the other hand, no obvious temporal variability was identified in the removal of COD. These results suggest that the RBF system is an effective barrier against NO 3-N, NH 4-N and COD in the Qingyang River, as well as those rivers with similar geological and climatic conditions refilled with reclaimed water.

“…A thicker vadose zone increases the possibilities for the attenuation of organic pollutants and, thus, reduces the groundwater vulnerability to contaminants [21,22]. However, so far, most research conducted at a laboratory scale concerning the fate of CECs considers columns that have 1-2 m length [23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Enhanced Removal of Contaminants of Emerging Concern through Hydraulic Adjustments in Soil Aquifer Treatment

Sallwey

Jurado

Barquero

et al. 2020

Water reclamation through the use of soil aquifer treatment (SAT) is a sustainable water management technique with high potential for application in many regions worldwide. However, the fate of contaminants of emerging concern (CECs) during the infiltration of treated wastewater during SAT is still a matter of research. This study investigates the removal capacity of 27 CECs during SAT by means of infiltration experiments into a 6 m soil column. Additionally, the influence of the hydraulic operation of SAT systems on the removal of CECs is investigated by changing the wetting and drying cycle lengths. Sixteen out of 27 CECs are efficiently removed during SAT under various operational modes, e.g., bezafibrate, diclofenac and valsartan. For six substances (4-methylbenzotriazole, amidotrizoic acid, benzotriazole, candesartan, hydrochlorothiazide and sulfamethoxazole), removal increased with longer drying times. Removal of amidotrizoic acid and benzotriazole increased by 85% when the drying cycle was changed from 100 to 444 min. For candesartan and hydrochlorothiazide, removal improved by 35%, and for 4-methylbenzotriazole and sulfamethoxazole, by 57% and 39%, respectively. Thus, enhanced aeration of the vadose soil zone through prolonged drying times can be a suitable technique to increase the removal of CECs during SAT.