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Measures for Securing Safety against PCBs at Takasago West Port

This document discusses the measures taken to secure safety against PCB contamination at the Takasago West Port project, including dredging of sediments and monitoring efforts. It also highlights the background for taking measures to permanently stabilize and assure the safety of the port.

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Measures for Securing Safety against PCBs at Takasago West Port

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  1. Measures for Securing Safety against PCBs at Takasago West Port Project of Capacity Building for Analysis and reductionmeasures ofPersistent Organic Pollutants in Serbia (Hyogo Environmental Advancement Association ) June 2014

  2. 1. Location of Takasago city Himeji Osaka Int’l Airport Takasago Osaka Kaneka Kobe Akashi The Sea of Harima Kansai Int’l Airport Awaji 1

  3. 2. Takasago West Port Banking Banking West Port カネカ高砂工業所 Kaneka Takasago Plant 2

  4. 3. Countermeasures to PCB sediments at Takasago West Port3-1 Background 1) In 1972 in Takasago West Port PCBs were detected in bottom sediments survey point:24 points, PCB concentrations: 4-3,300 mg/kg 2) Source of contamination a) PCBs were contained in wastewater discharged by Company M(Paper Mill) b) Kaneka (producing PCBs) may have discharged the wastewater to West Port 3) Implementation of Measures(Dredging of bottom sediments of West Port and solidifying dredged sand & soil) Build-up the solidified sand and soil near West Port → Takasago West Port Banking The 1st phase: September 1974 – March 1975 The 2nd phase: August 1975 – August 1976 4) Bottom sediment survey just after the dredging completed 40 survey points : ˂ 0.01 – 4.53mg/kg (tentative removal standard of bottom sediments : 10mg/kg) 5) Monitoring Takasago city and industrial firms (Kaneka and Company M) are continuously performing monitoring Monitoring : Survey twice a year the underground water, rainwater, ambient air in the vicinity of the banking and West Port →maintaining the levels of the lower quantitation limit or less 3

  5. 3-2 PCBs level of Takasago West Port PCB concentration of sediments at West Port : mg/Kg 4 TheSeaofHarima

  6. 3-3 The volume of the dredged soil of the banking 5

  7. 3-4 Dredging and construction schedule of West Port The 1st Phase schedule banking Solidification curing pond Sand carrier Sludge storage & solidification Taking out Carry out constructing Dredging unloading The 2nd Phase schedule Mud sending pipe Mud sending pipe Solidification banking Solidification plant oozer pump Dredging vehicle with oozer pump sludge constructing solidification Dredging Mud sending Mud sending 6

  8. 3-5 Location of Banking 7

  9. 3-6 Cross-section of banking Water impermeable sheet asphalt 技術委員会ｐ１４ Mountain earth 2nd phase banking asphalt 1st phase banking asphalt Concrete retaining wall Carbide residue etc. 8

  10. 3-7 Construction system 工事体制 Administrative Chief Hyogo pref., Water Quality Control Division Director Administrative Deputy Chief Takasago Municipal EnvironmentalPollutionPrevention Office Director (Air Quality & Dust Sector) (Construction Sector) (Water Quality & Commercial Fishing Sector) Person in charge: Deputy Director Water Quality Control Division Person in charge: Deputy Director iviAir Quality Control Division Person in charge: Deputy Director Port & Harbor Division Water quality control Div. Envi’tal Pollution Prevention Office Air quality control Div. Institute for Envi’tal Studies Kakogawa Civil Engineering Office Municipal construction section Institute for Envii’tal Studies Envi’tal Pollution Prevention Office Port & Harbor Division Duties-in-charge Duties-in-charge Duties-in-charge 1.Maintain, manage & monitor construction work 2.Supervise construction work 3.Understand the present situation of construction work 4.Supervise fishing net and ON/OFF of protector 5.Supervise IN/OUT of ships 6.Anything required related with construction work 1.Monitor prevention of scattering of dust 2.Measure PCB concentration in ambient air 3.Anything required related with air quality and dust 1.Develop Monitoring Plan 2.Measure water quality & sediments based on monitoring plan 3.Manage & monitor secondary environmental pollution prevention facility 4.Investigate fish & shellfish based on monitoring plan 5.Anything required related with water quality and commercial fishing Industrial firms 9

  11. 3-8 Management after taking countermeasures ●：underground water ●：air ●：rainwater, sea water or riverwater banking Takasago West Port Company M Kaneka 10

  12. 4. Background for taking measures to permanently stabilize & assure its safety 1. July 2005Formulate “Takasago Regional Development” Plan Safety of banking became controversial due to the plan 2. June 2006Establish “Technical Committee on PCB banking” Five academic experts were nominated 3. Sept.2007Technical Committee on PCB banking submitted Report Validate the safety of the banking. Study measuresto permanently stabilize the PCB banking 4. Mar. 2008Establish“Council for Promoting Redevelopment of Takasago West Port” Five academic experts, two administration officers, seven citizen representatives and three related company people were selected Study the improvement of port and harbor, countermeasures to permanently stabilize the PCB banking, water amenity space and access plan Hold a meeting to explain to local residents and approved containment method 5. Apr. 2009 Council for promoting redevelopment of Takasago West Port submitted Report 6. June 2010 Establish “Technical Committee on Redevelopment of Takasago West Port” Six academic experts were nominated 7. Mar. 2011Technical Committee on Redevelopment of Takasago West Port submitted Report 8. Feb. 2013Construction work for permanently stabilizing PCB banking started (Management of design and construction by Construction sector, Hyogo pref.) 9. May 2015Construction work for permanently stabilizing PCB banking completed 11

  13. 4-2 Technical Committee 1. Technical Committee on PCB banking at Takasago West Port Chair person: FUJITA Masanori (prof. emeritus at Osaka Univ.) member: KIMBARA Kazuhide (associate prof., Okayama Univ.) TOKIDA Kenichi (prof., Graduate School of Eng., Osaka Univ.) NOMA Yukio (Director, National Institute for Environmental Studies) MICHIOKU Kohji (prof., Graduate School of Eng., Kobe Univ.) 2. Technical Committee on redevelopment of Takasago West Port Chair person: FUJITA Masanori (prof. emeritus at Osaka Univ.) member: KITAMURA Yasutoshi (prof. emeritus at Kobe Univ.) DEGUCHI Ichiro (prof., Graduate School of Eng., Osaka Univ.) TOKIDA Kenichi (prof., Graduate School of Eng., Osaka Univ.) MICHIOKU Kohji (prof., Graduate School of Eng., Kobe Univ.) KAWAI Hiroshi (prof., Kobe Univ.) * The title mentioned is at the time of nomination 12

  14. 4-3 Report by Technical Committee on PCB banking at Takasago West Port 1. Validate the safety of banking (1) Survey 1) Analysis: a. banking (boring 2 points)→soil investigation, PCB analysis b. surrounding area of banking (bored 6 points for 20m) →soil survey& analysis 2) Confirmation: monitoring data up to date or documents like drawings (2) Result：No PCB leakage was found in the surrounding area. No possibility of PCB leakage due to complete impermeablesheet covering solidification soil containing PCB. (3) Study on the structure of banking 1) Embankment failure In the event of large-scale earthquake, liquefaction occurs and may lead to slope failure (partially collapse) 2) Soil subsidence : Embankment is subsided.No need to worry about the target area for further unbalanced subsidence 3) Tsunami : Tsunami with an estimatedmaximum height will not reach the banking 4) Tidal wave : High wave with an estimated maximum height will noterode the slope face much 5) Heavy rain :No flood damage of banking due to heavy rain and tidal wave with estimated maximum level 6) Revetment:Strength poverty is found partially and have the potential for breakdown in the event of a large-scale earthquake 2. Permanent countermeasures of banking Studied 3 cases as countermeasures and adopted the containment measurebecause of the lowest risk 13

  15. 4-4 Measures to permanently stabilize & assure its safety Countermeasures shown in the Committee Report Countermeasures shown in the Committee Report B. Decomposition treatment C. Containment A. Remove and dispose all B Remove all PCB banking, decompose at neighboring area and backfill at the original banking (or dispose at final disposal area C1 Cover the upper portion of banking A1 Remove all PCB banking, decompose and dispose at final disposal area Good quality earth Non woven fabric sheet + water Impermeable sheet + non woven fabric sheet Banking Carry out Final disposal site Banking decomposition Existing asphalt covering Backfill at banking Decomposition at neighboring area Banking A2 Remove all PCB banking and dispose at final disposal area without decomposition Solidified banking soil Cover upper portion Carry out C2 Cover the upper portion and construct water impermeable underground earth retaining wall Final disposal site Banking Carry out Final disposal site Image of covering lid for excavating site Banking Covering Image of covering lid for excavating site 10t box car Water impermeable underground earth retaining wall Period 20 yrs (decomposition & reclamation) 10 yrs (reclamation) Period 20 yrs Period 2 yrs Cost $1.5 bil Cost $75mil (covering $40 mil & construction $35 mil) Cost $1.57 bil (decomposition & reclamation) $400 mil (reclamation) Evaluation : 1. Construction of large scale treatment facility is necessary 2. Scattering of dust to the surroundings is anticipated during the long construction period Evaluation : 1. Completion of the work is expected in short period and no risk for scattering of dust 2. Plan C2 ensures safety in the event of a large scale earthquake etc. Evaluation:1. Secure facilities with effective acceptance system is the problem to be solved 2. Scattering of dust to the surroundings is anticipated during the long construction period 14 * Reinforcement of surrounding retaining wall is necessary in any countermeasures to be taken

  16. 4-5 Containment method Covering top layer = water impermeable sheet + covering soil North Side South Side covering soil Asphalt layer Public Wharf Seaside road 2nd Phase Solidified soil containing PCB city road 1st Phase Solidified soil containing PCB Reinforce retaining wall Carbide residue etc. Liquefaction layer Supporting ground Water impermeable underground earth retaining wall Countermeasure construction work 15

  17. 4-6 Overview of PCB banking countermeasure project Pressing banking Covering soil Reinforce retaining wall Solidified soil Water impermeable underground earth retaining wall Water impermeable underground earth retaining wall Covering of upper portion Reinforce retaining wall 16

  18. 4-7 Success factors of the PCB banking countermeasure project 1.Transparency 　　・Technical committee orCouncil for Promoting Reconstruction was held with open doors including the mass media ・Any documents or the minutes of the proceedings of the committee were available in internet 　　・Takasago city issued public relations magazines 　　・Meetings to explain to local residents were held →Opinions of the public were reported and studied at the committee 2. Soliciting evaluations from the viewpoints of academic experts 　　・Chose the influential and the right person (Hyogo prefecture) 　　・Based on the data (soil survey, soil analysis or preserved documents etc.), experts evaluated from the academic point of view 　　・Consider in a wide range free from conditions like construction cost etc. and suggested the best strategy →offer persuasion 3. Administrative guidance 　　・Give priority to gain the understanding of local residents (Chose citizen representative as Council member. Held meeting and explained to local residents ） 　　・The administrative body (prefecture) supervised the design and managed the countermeasure construction work 　　・Build reliability between the administrative body and related industrial firms 17

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