Bioremediation of sediment impacted with PAHs
The effectiveness of DARAMEND® bioremediation was demonstrated on 150 tons of sediment dredged from PAH impacted regions of Hamilton Harbour. The harbour is adjacent to a heavily industrialized area and the sediments have been impacted with a variety of contaminants including residue from coal coking operations for the steel manufacturing industry.
PAH concentrations exceed 1,400 mg/kg in a large portion of the harbour.
At this site the technology involved a solid phase aerobic approach utilizing indigenous microorganisms in a prepared bed (land treatment). The technology was site specific and involved the addition of nutrients and proprietary organic amendments (DARAMEND®) to optimize the rate of microbial activity in the sediment. Prior to initiation of treatment, the dredged sediment was allowed to passively dewater within the bioremediation cell. During treatment close control of sediment moisture content was maintained through irrigation and tillage. Tilling was accomplished using specialized rotary tillage equipment with an effective tilling depth of 60cm.
Total PAH concentrations were reduced from 1139mg/kg to 110 mg/kg after 312 days of treatment. With the exception of benzo(a)pyrene all regulated PAH isomers were below the guidelines after 245 days of treatment. Benzo(a)pyrene was reduced below its respective target after 312 days.