Varying attenuation of trace organic chemicals in natural treatment systems – A review of key influential factors

The 21st century water quality challenges for managed aquifer recharge: towards a risk-based regulatory approach

“…Such complex and uncertain risks can be dealt with through decades of experience in water quality improvement and management in MAR, furthered by targeted research—for example, a study that evaluates the die-off of plant pathogenic bacteria when stormwater is used to recharge a brackish anoxic aquifer in the Netherlands can enhance confidence in the recovered water’s intended use for irrigation (Eisfeld et al 2021 ). Knowledge of biodegradation of trace organic chemicals or contaminants of concern has been advanced through the application of genomic markers to infer the prevailing trophic state of microbial communities in a MAR scheme, and subsequently, predict favorable conditions for removal (Filter et al 2021 ). While it is understood that microbially mediated processes are an important control on water quality, and in particular, water quality improvement, approaches are required to assess aquifer microbial communities, their potential to augment treatment, response to changing geochemical conditions, and ultimately the sustainability of treatment.…”

Analyzing (Initial) Biotransformation Reactions as an Organizing Principle for Unraveling the Extent of Trace Organic Chemical Biotransformation in Biofiltration Systems

“…They confirmed that bacteria in column b1 were able to biotransform 15 of 18 group 2 substances. Only nine of those substances showed further transformation in sands from the subsequent columns b2–b4, including, for example, paracetamol, ibuprofen, and naproxen, which are efficiently removed in most column and field studies . Interestingly, the three sulfonamides, sulfamethoxazole, sulfadiazine, and sulfapyridine, were not transformed in batch experiments with sand from column b1, although they were well removed in column experiments.…”

“…It is generally assumed that environmental conditions that include low concentrations of biodegradable dissolved organic carbon (BDOC) favor the establishment of highly diverse microbial communities, which are adapted for biotransformation of refractory carbon sources. , Indeed, enhanced biotransformation of certain TOrCs has been observed under such conditions in conventional activated sludge and managed aquifer systems. , However, for other substances, improved removal in the presence of readily degradable carbon sources has been observed in controlled laboratory column studies, correlating with microbial activity as indicated by biomass or ATP analyses, oxygen depletion, or removal of DOC. , Furthermore, several substances show variable biotransformation efficiencies, even in systems with no obvious difference in substrate and redox conditions …”

Transformation of potentially persistent and mobile organic micropollutants in column experiments

“…Thereby, infiltrating water undergoes a series of physical, chemical and biological changes resulting in the attenuation of contaminants. Previous studies revealed the attenuation of several OMP through BF [ [14] , [15] , [16] , [17] , [18] ]. Different factors such as redox condition, temperature, pH, porosity of the medium and travel time, play an essential role in the performance of the BF system [ 15 , 19 , 20 ].…”

“…Previous studies revealed the attenuation of several OMP through BF [ [14] , [15] , [16] , [17] , [18] ]. Different factors such as redox condition, temperature, pH, porosity of the medium and travel time, play an essential role in the performance of the BF system [ 15 , 19 , 20 ]. Controlled sand columns are generally used to evaluate the fate of OMP by simulating BF processes.…”