A feasible method for the composition analysis and chemical remediation of clogging matter in subsurface flow constructed wetlands

The problem of clogging, especially biological clogging, makes the long-term operation of subsurface flow constructed wetlands challenging. This study focused on the two subsurface flow constructed wetlands receiving reclaimed water near the Tuhai River of Shandong Province, aiming to provide a feasible method for the composition analysis and chemical remediation by H₂O₂ solution of clogging matter. The compositions and distributions of clogging matter in these two wetlands were analyzed, and the effects of H₂O₂ solutions with different mass fractions on proteins, polysaccharides, nucleic acids, and humic acids in the organic clogging components were studied. The two case studies indicated that the contents of clogging matter in the two subsurface flow constructed wetlands varied greatly due to the operation time and operation mode, and the proportion of inorganic components was higher than that of organic components. The organic components of the clogging matter were mainly proteins and humic acids, with very small amounts of polysaccharides and nucleic acids. In addition, the H₂O₂ solution with a mass fraction of 10% had a good removal effect on proteins and humic acids in the wetland substrates, which also could increase the permeability coefficient of the substrates without causing a large negative impact on the temperature and pH value of the wetland systems. This article proposed a simple, economical, environmentally friendly method for analyzing and remediating biological clogging of subsurface flow constructed wetlands, which was expected to be widely used in situ remediation of clogging matter.