JAUE2012-007: Reed Bed for Phytoremediation of PAH-Contaminated Sludge

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are easy accumulated in the sewage sludge produced in the process of wastewater treatment due to their hydrophobicity and high organic affinity. Onsite experiment on reed bed for surplus activated sludge treatment was presented, the research focused on PAHs contents variation in stabilized sludge after two years loading and one year resting. The reed bed was constructed in the Wastewater Treatment Plant, Dalian Development Zone, Lioaning province, China. The PAHs content in the influent sludge was averaged 5.69mg/kg (DW), including 48.01% of low-molecular-weight PAHs (2-3 ring PAHs), 27.1% of middle-molecular-weight PAHs(4 ring PAHs) and 24.89% of high-molecular-weight PAHs(5-6 ring PAHs). The PAHs contents in stabilized sludge are obviously lower than that of feed and averaged 2.08mg/kg(DW), about sixty one percent of PAHs were removed. In the stabilized sludge, the low-molecular-weight PAHs removals predominated (66.42%) in all samples, then middle-molecular-weight PAHs (57.08%) and high-molecular-weight PAHs (32.45%). At the same time, the PAHs contents in stabilized sludge have obviously spatial distribution, i.e., bottom layer sludge has the highest PAHs content, then middle layer sludge and surface layer sludge in the reed bed.