Influence of pH on the release of colloidal and dissolved organic matter from vertical flow constructed wetland surface sludge deposits

pH control on organic and organo-mineral colloids carrying major and trace elements in leachates of wetland sludge deposits

“…S1 of supporting information). A large investigation on the release of colloidal and dissolved organic matter from same samples have been already performed by Banc et al [15]. The quantity and the molecular size of the leached organic molecules was strongly affected by the pH.…”

“…Solid deposit samples investigated by Banc et al, [15] were used in this study. SD were sampled in winter time from the surface solid layer of the first-stage filter of the VFCW treatment plant of Vercia (France).…”

“…Ultracentrifugation tubes were previously rinsed several times with a 0.1M NaOH solution followed by Milli-Q water to guarantee background concentrations of dissolved organic carbon (DOC) below 0.1 mg.L -1 in the ultrafiltrate. The ultrafiltrates collected from the ultrafiltration of all the leachates obtained from the leaching assays were (i) analyzed for organic carbon concentration [15] and (ii) prepared for inorganic major and trace element concentrations analysis. For the latter, samples were evaporated and pre-digested with 14.6 mol.L -1 distilled HNO 3 at 90°C overnight.…”

“…This risk can occur due to possible variations in treatment operating conditions (such as periods of flooding or pH fluctuations) or when the solid is extracted and used for its potential fertilizing and agronomic properties, which can lead to further spread of contaminants. Banc et al, [15] investigated the mobilization of organic colloids and looked at their molecular size and their aromaticity. The nature of the organic molecules generated by the SD were highly dependent of the pH conditions.…”

Organic carbon, and major and trace elements reside in labile low-molecular form in the ground ice of permafrost peatlands: a case study of colloids in peat ice of Western Siberia

“…The use of this technique allows for straightforward assessment of a colloidal and low molecular weight pool of elements with minimal contamination from the environment; it is easily performed both in the eld and in the laboratory. 12,[28][29][30] The ltered water was immediately (within 15 minutes) processed by centrifugation, using an Eppendorf 5804 centrifuge at 3500g. The possibility of colloid generation during oxidation of porewater is not excluded but unlikely given the high stability of these colloids over time.…”