Adsorption of Organic Stormwater Pollutants onto Activated Carbon from Sewage Sludge
Journal article, 2017
Adsorption filters have the potential to retain suspended pollutants physically, as well as attracting and
chemically attaching dissolved compounds onto the adsorbent. This study investigated the adsorption of
eight hydrophobic organic compounds (HOCs) frequently detected in stormwater e including four
polycyclic aromatic hydrocarbons (PAHs), two phthalates and two alkylphenols e onto activated carbon
produced from domestic sewage sludge. Adsorption was studied using batch tests. Kinetic studies
indicated that bulk adsorption of HOCs occurred within 10 min. Sludge-based activated carbon (SBAC)
was as efficient as tested commercial carbons for adsorbing HOCs; adsorption capacities ranged from 70
to 2800 mg/g (Cinitial ΒΌ 10e300 mg/L; 15 mg SBAC in 150 mL solution; 24 h contact time) for each HOC. In
the batch tests, the adsorption capacity was generally negatively correlated to the compounds' hydrophobicity
(log Kow) and positively associated with decreasing molecule size, suggesting that molecular
sieving limited adsorption. However, in repeated adsorption tests, where competition between HOCs was
more likely to occur, adsorbed pollutant loads exhibited strong positive correlation with log Kow. Sewage
sludge as a carbon source for activated carbon has great potential as a sustainable alternative for sludge
waste management practices and production of a high-capacity adsorption material.
stormwater management
sludge-based activated carbon
organic contaminants
adsorption