Treatability testing for potential ex-situ treatment of marine sedimentswithin the Kai Tak Approach Channel (KTAC), as part of the South East KowloonDevelopment project, was performed using the BioGenesisSM Sediment Washing technology.The sediment washing technology is one of the treatment methods under considerationby the Territory Development Department of the Government of the Hong KongSpecial Administrative Region. The ex-situ treatability testing was conducted on approximately800 liters of homogenized marine sediment composited from seven samplinglocations in the KTAC. BioGenesis Enterprises, Inc. (BGE), USA, conducted this testingand MWH Americas, Inc. (MWH) designed the treatability program and provided supervision.The testing program proceeded in three stages: initial chemical/physical examination,optimization, and treatment validation. The KTAC sediment consisted of essentiallysandy organic silt, with high concentrations of a wide variety of organic and inorganiccontaminants. Four mixtures of proprietary chemicals/reagents (varying combinations ofsurfactants and chelating agents), were tested. Analytical results for treated sedimentshowed that the BioGenesis SM technology produced significant reductions in inorganicand organic compounds; inorganics were reduced from 30% to greater than 99%, whileorganics were reduced from 23% to greater than 92%. The total organic carbon (TOC)content was reduced by 79%, from 4.4% in the untreated sediment to 1.1% in the treatedsediment. Other chemical species, such as ammonia, acid volatile sulfide (AVS), andsulfide, were all reduced by more than 99%. Based on the results of the treatability testing,the KTAC contaminated marine sediment is treatable in terms of sediment phys icalcharacteristics, odor control, and contaminant removal using the BioGenesisSM technology.Both treatment validation runs produced treated TOC concentrations at approximately1.1%, which is important in terms of reducing future potential methane generationshould the cleaned sediments be reused as fill. Results indicate the following conclusions:Ex-situ sediment washing using the BioGenesisSM technology is applicable to the remediationof contaminated KTAC sediment; the proprietary chemical mixture can easily beoptimized to achieve cleanup goals for the project; odor control compounds can beapplied to the KTAC marine sediments during dredging and treatment to control odorsarising from the untreated sediment; and the necessary information required to conductpilot-scale treatment of the KTAC contaminated sediments was identified.
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