The Fate of Dissolved Organic Matter (DOM) During Bank Filtration under Different Environmental Conditions: Batch and Column Studies

Abstract

Dissolved organic matter (DOM) in source water highly influences the removal of different contaminants and the dissolution of aquifer materials during bank filtration (BF). The fate of DOM during BF processes under arid climate conditions was analysed by conducting laboratory—scale batch and column studies under different environmental conditions with varying temperature (20–30 °C), redox, and feed water organic matter composition. The behaviour of the DOM fractions was monitored using various analytical techniques: fluorescence excitation-emission matrix spectroscopy coupled with parallel factor analysis (PARAFAC-EEM), and size exclusion liquid chromatography with organic carbon detection (LC-OCD). The results revealed that DOM attenuation is highly dependent (p < 0.05) on redox conditions and temperature, with higher removal at lower temperatures and oxic conditions. Biopolymers were the fraction most amenable to removal by biodegradation (>80%) in oxic environments irrespective of temperature and feed water organic composition. This removal was 20–24% lower under sub-oxic conditions. In contrast, the removal of humic compounds exhibited a higher dependency on temperature. PARAFAC-EEM revealed that terrestrial humic components are the most temperature critical fractions during the BF processes as their sorption characteristics are negatively correlated with temperature. In general, it can be concluded that BF is capable of removing labile compounds under oxic conditions at all water temperatures; however, its efficiency is lower for humic compounds at higher temperatures.

Water quality changes and organic matter removal using natural bank infiltration at a boreal lake in Finland

“…According to earlier studies, the residual organic matter consists of hydrophilic, neutral, low molecular weight organics (e.g., Dietrich et al 2013;Lindroos et al 2002;Parsons et al 2004). At Iso Tiilijärvi, NOM removal efficiency was not correlated to temperature (Jylhä-Ollila et al 2019), which is in line with earlier results (e.g., Brugger et al 2001;Diem et al 2013;Massmann et al 2006), whereas on the other hand, Abdelrady et al (2018) reported a correlation between the NOM removal and temperature and Diem et al (2013) suggested that the easily degradable NOM is decayed in soil at all temperatures within the first hours of infiltration. Rapid decay could explain the absence of seasonality in NOM removal even though bacterial activity is known to be temperature-dependent.…”

“…In these reference studies, DOC removal during the first 15 days after infiltration varied between 33 and 62% and the total removal between 37 and 100%. The large variation in removal efficiency is probably due to variable environmental conditions, aquifer properties and NOM Maeng et al 2011 quality (Maeng et al 2011;Gross-Wittke et al 2010;Abdelrady et al 2018). As the reduction percentage at the studied Iso Tiilijärvi infiltration site was high, the results suggest that an aquifer can effectively remove NOM without losing its capacity over the long term, as long as the surface-water quality and the aquifer properties are in a range comparable to the studied conditions.…”

Analysis of the Performance of Bank Filtration for Water Supply in Arid Climates: Case Study in Egypt

“…Moreover, SUVA 254 values of NR, ADL, BF1, BF2, and GW were 1.56, 1.33, 2.16, 2.04, and 2.73 L/mg•m, respectively, which indicates that the bank filtrate and ambient groundwater had relatively higher aromatic characteristics than the surface water sources. This observation could be attributed to the (i) dissolution or desorption of soil organic matter into the filtrate water, which is significantly increased at high temperatures [44,45], (ii) accumulation and subsequent degradation of particulate organic matter (e.g., Phytoplankton) during the filtration process that augments the organic concentration in the bank filtrate [46], and (iii) effect of mixing the infiltrated water with the ambient groundwater, which has a higher concentration of organic matter. The phenomenon of enrichment of the organic content of the bank filtrate was also reported at BF wells along the Lot River (France) and Lagoa do Peri Lake (Brazil) [10,47].…”

Characterisation of the impact of dissolved organic matter on iron, manganese, and arsenic mobilisation during bank filtration

“…The third column was fed with DCW mixed with water-extractable organic matter (WEOM) that had high humic content. The procedures used for WEOM preparation are described in detail in (Abdelrady et al, 2018). The last column was fed with non-chlorinated tap water (NCTW), representing low-organic-matter-content water.…”

“…On average, the FI of FC1 and FC2 increased by a factor of two and three, respectively, during the filtration process. The enrichment of humic compounds in the effluent water might be attributed to: (i) the dissolution of soil organic compounds into the filtrate water, (ii) the presence of microorganisms that are able to bio-transform the labile organic matter into more condensed and refractory compounds (Abdelrady et al, 2018). DCWW and WEOM had the highest concentration of protein-like fluorescent compounds.…”