Challenges of Performing Contaminated Sediment Remediation and Restoration in China and Taiwan Brian J. Mastin, Ph.D. Dave Renfrew Jerry Chen Samuel Wu Ph.D. Dredging 2012 – San Diego, CA October 23, 2012 SOUTHERN RESEARCH INSTITUTE Legendary Discoveries. Leading Innovation.

Overview Remediation/Restoration Case study – An-shun Remediation Project Case study – Xiawangang River Remediation Project Sediment management projects conducted in isolation of watershed objectives are not typically sustainable

Integrated Sustainable Sediment Management

Phased Approach to Sediment Remediation & Restoration Implementation Source Control & Define Objectives Sampling & Analysis (RI) Bench-scale Feasibility (FS) Pilot-scale Implementation Operations & Maintenance – Sustainability Full-scale Implementation Design & Engineering Identification of Sources Best Management Practices Prevent Recontamination Identification of Sources Best Management Practices Prevent Recontamination Nature, Magnitude & Extent Goodness-of-fit Scalability Performance (effectiveness & efficiency) 2 o & 3 o Treatment Timeline Nature, Magnitude & Extent Goodness-of-fit Scalability Performance (effectiveness & efficiency) 2 o & 3 o Treatment Timeline 90% complete Incorporate contractor suggestions 90% complete Incorporate contractor suggestions Proof of Concept Remediation, Restoration, Rehabilitation Proof of Concept Remediation, Restoration, Rehabilitation

Risk Management Goals and Objectives for Successful Remediation Typically use several sediment quality metrics to determine the contaminants of concern and biological risks for each Site based on established benchmarks & multiple lines of evidence (weight of evidence approach). 1. Analytical endpoints and thresholds 2. Toxicity to sentinel test species 3. Benthic community assessment (simultaneously evaluated with habitat conditions) 4. Biological tissue concentrations (i.e., bioaccumulation in benthic macroinvertebrates and/or fish species)

An-shun Remediation Project xian-gong community Lu-Er community Remediation Site Taiwan Strait Tainan City Taiwan

Preliminary Site Investigation  Sediment: < 1,400 mg/kg Hg  Contamination above soil control standard to > 90-cm  Sediment: < 1,400 mg/kg Hg  Contamination above soil control standard to > 90-cm SEAWATER POND ALKALI- CHLORINE PLANT PENTACHLORO- PHENOL PLANT Hot Spot Spot Hot Spot Hot Spot Weirs/Outfalls Pond A Pond B Sediment/soil control standards Hg: 10 mg/kg Total Hg Dioxin: 500 ng-L-TEQ/kg

Objectives 1)Perform turn-key remediation of mercury (Hg) and dioxin contaminated sediment in Pond B. 2) Incorporate separation of “clean” sand for beneficial reuse on site.

Sediment Management Plan Sediment Characterization Sediment Excavation Hydraulic dredging Sand Separation – hydrocyclones Soil washing WWTP Verification & Additional Remediation e.g., capping, backfilling Effluent “Clean” Sand for Beneficial Reuse Contaminated Fines: Dewatered & Consolidated

Remedial Investigation Results

Pond B Pond A Contaminated Sediment Pond A: ~125,000-m 3 Pond B: 116,400-m 3

Xiawangang River Remediation Project Zhuzhou City, China

Objective Perform a sediment remediation and environmental rehabilitation of 4-km of the Xiawangang River in order to decrease the human health and environmental risks associated with metals-contaminated (e.g., Cd, Hg, As, and Pb) sediment and water.

Xiawangang River Overview WESTON Proposed Section Surface Area (meters 2 ) Total Volume Sediment (meters 3 ) Total Volume By Particle Size (meters 3 ) GravelSandSiltClay 14,7965,5841,4643, ,7072, , ,7443, , ,6972, ,0012, ,4896,0771,2512,4392, ,2098,2001,0962,9443, ,0146, ,2362, ,0961, TOTAL28,88736,8917,14117,26712,9302,427

Metal-contamination Weston River Section Mass of Metal within Each Section (metric tons) Cadmium (Cd) Chromium (Cr) Copper (Cu) Lead (Pb) Mercury (Hg) Nickel (Ni) Arsenic (As) Zinc (Zn) TOTAL Note: Results represent the volume of sediment from each River section multiplied by the 2011 average sediment concentration (n=29) for the 20-cm depth horizon and the 100-cm depth horizon.

Challenges - Site Access & Equipment Selection

10 Remediation Plans

Schedule Section Transect (m) In situ Sediment Volume (m3) Total Mass* (dry metric tons) S/S Volume** (m3) Timeline to Completion + (days) Construction Sequence ,58412,6964, ,7904,0681, – 28405,43611,9484, – – 20202,0024,1361, – 19206,07712,5624, – 14408,20017,4247, – 7806,22913,2325, – 2301,1932, TOTALs36,89179,53029,750 (59,500 mt) 95

Challenges to Remediation Extremely high contaminant concentrations Multiple exposure pathways The overall objectives and beneficial uses not defined Remediation and rehabilitation performance goals were not defined Limited in-channel footprint for sediment management Restricted access due to active industrial facilities, power lines, pipelines, steep and unstable channel banks, railways and roads Incomplete performance expectations for bank stabilization and source control

Additional Challenges Previously conducted remedial investigations and feasibility studies were incomplete “Ground-truthing” of project objectives and performing data gap investigations was not performed No regional guidance on development of a Stormwater Management Plan No regional guidance on point and nonpoint source control No operation and monitoring component No risk-based effects guidance for this type of watershed Equipment availability What other surprises?????

Thank you!! Questions??

SOUTHERN RESEARCH INSTITUTE Legendary Discoveries. Leading Innovation. Brian J Mastin, PhD Dave Renfrew