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

• Organic matter from VFCW's sludge deposits is less soluble after aging. Truly dissolved organics (<3kDa) are leached under acidic conditions. Larger colloids (>3 kDa) alkaline around neutrality very aromatic. Leached all poorly aromatic regardless of pH and molecular size. The rapid development vertical flow constructed wetlands (VFCW) in Europe throughout the world has induced a growing concern on conditions management their surface (SD). leaching organic components SD was explored this study with respect to potential impact biochemical oxygen demand (BOD) role as complexing agents release trace contaminants. aromaticity size compounds investigated over large range pHs. Experimental results showed that aqueous solution influenced concentration characteristics OC. Around natural suspensions (6 8), truly (<3 exhibited high content. Under (pH > (>30 were found predominant, exhibiting low pH. < 6), hydrophilic leached. Comparison concentration, OC 14-year 7-year suggested ageing reduced sensitivity may improve agronomic properties.