Land Contamination: Technical Guidance on Special Sites: Acid Tar ...
Land Contamination: Technical Guidance on Special Sites: Acid Tar ... Land Contamination: Technical Guidance on Special Sites: Acid Tar ...
5.4 Site Evaluation Check-listThe purpose of the site evaluation is to review all the risk based information to decidewhether the estimated risks are unacceptable, taking into account the nature/scale of the risksand any technical uncertainties.A check-list is provided below summarising issues specific to acid tar lagoons that need to beconsidered alongside the Model Procedures.Have the following specific considerations for acid tar lagoons been included in thesite evaluation?The physical risk to visitors/trespassers/contractors and whether this is adequatelyaddressed, for example by fencing and warning signs.The physical risk associated with topography, e.g. land slide with release of tars,potential for breach of a bund wall.The chemical risk to visitors/trespassers/fauna and flora associated with the high acidityof acid tars and also toxicity considerations.The potential for release of toxic gases (especially sulphur dioxide, but also hydrogensulphide), vapours (especially BTEX compounds) and dusts, and the associatedinhalation risks.Factors that influence the risk to controlled waters, including solubility of tars, mobilityof free phase oils and tars and degradation potential in the unsaturated zone and inpolluted groundwater.The fire risk (including starting of a fire by trespassers/visitors) and build up ofpotentially explosive concentrations of flammable gases in buildings.The uncertainties associated with variability within the lagoon and also any wastes ofquite different origin that may have been disposed of with the acid tars.The potential for gas generation and migration (taking account also of any co-disposalof domestic wastes).Effect of pH on the environmental behaviour of contaminants (e.g. increased metalmobility, interaction with natural minerals).R&D
6. REMEDIATION ASPECTSKEY QUESTIONS ANSWERED IN THIS SECTION1. Which remediation technologies could be appropriate?2. What are the main constraints and advantages to each of the applicable remediationtechnologies/engineering methods?3. What are the anticipated perception/community impacts of the remediation technologies?4. How can the remediation process be validated?6.1 ScopeThis section provides detail on the most applicable remediation technologies which arecurrently available (or are likely to be available in the near future) on a commercial scalewithin the UK. The intention of this section is to enable the reader to select a short list ofappropriate remediation technologies and to highlight the key issues that will need to beconsidered in the remediation design. It does not provide detailed guidance on remediationdesign.6.2 Principal Remediation Technologies6.2.1 Civil engineering approachesCover Systems and Barriers• The use of cover systems is generally not appropriate for acid tar lagoons as there is atendency for most capping materials to move gradually downwards through the massof tarry material, with the acid tar eventually replacing it at the surface;• the downwards movement of capping materials and upwards movement of acid tarscan also result in potential disturbance to vertical barriers installed as part of thecapping system.Encapsulation• Various proprietary polymer-based and inorganic cement-based encapsulationtechniques were attempted in the 1970s, but neither process appears to have provedsuccessful in the long term;• these techniques may be considerably more expensive than neutralisation and landfill.Excavation and Disposal• Acid tars and incorporated wastes that cannot be segregated easily will be deemedspecial wastes and will need to be dealt with and transported appropriately anddisposed of at a suitably licensed facility;R&D
- Page 1 and 2: Land Conta
- Page 3 and 4: CONTENTSFOREWORDiGLOSSARYii1. Intro
- Page 5 and 6: FOREWORDPart IIA of the Environment
- Page 7 and 8: CresolsCreosoteDCRDesorptionDesulph
- Page 9 and 10: PVCRCRASelosafeSodium saltsSodium h
- Page 11 and 12: 1. INTRODUCTION1.1 BackgroundThis r
- Page 13 and 14: SECTION 2: INDUSTRIAL PROCESS/FACIL
- Page 15 and 16: 1.5 Linkages Between the Gu
- Page 17 and 18: 2.1.2 Overview of acid tar lagoon s
- Page 19 and 20: Overall CommentsAcid tars can be of
- Page 21 and 22: White Oil• Acid tar lagoons from
- Page 23 and 24: Box 2.5 Scenario: Acid tar disposal
- Page 25 and 26: 3. CHEMICAL AND PHYSICAL CHARACTERI
- Page 27 and 28: Table 3.1 - General Physical Charac
- Page 29 and 30: The chemicals listed in Table B.1,
- Page 31 and 32: 4.2.3 Common mistakesIt is possible
- Page 33 and 34: Geophysical methods, such as resist
- Page 35 and 36: Investigation locations will need t
- Page 37 and 38: • gas chromatography by simulatin
- Page 39 and 40: 5.2.2 Water environmentThere is lit
- Page 41: 5.3 Assessment of Investigation Dat
- Page 45 and 46: 6.2.5 Solidification and stabilisat
- Page 47 and 48: Box 6.1 Example of Remediation of A
- Page 49 and 50: 6.3 Natural AttenuationNatural atte
- Page 51 and 52: Table 6.1 - Remedial Options/Techni
- Page 53 and 54: Table 6.2 - Remedial Options/Techni
- Page 55 and 56: 6.4 ValidationThe principles of val
- Page 57 and 58: • all personnel should follow a d
- Page 59 and 60: Verschueren (1983) Handbook of Envi
- Page 61 and 62: USEPA. Innovative Site Remediation
5.4 Site Evaluati<strong>on</strong> Check-listThe purpose of the site evaluati<strong>on</strong> is to review all the risk based informati<strong>on</strong> to decidewhether the estimated risks are unacceptable, taking into account the nature/scale of the risksand any technical uncertainties.A check-list is provided below summarising issues specific to acid tar lago<strong>on</strong>s that need to bec<strong>on</strong>sidered al<strong>on</strong>gside the Model Procedures.Have the following specific c<strong>on</strong>siderati<strong>on</strong>s for acid tar lago<strong>on</strong>s been included in thesite evaluati<strong>on</strong>?The physical risk to visitors/trespassers/c<strong>on</strong>tractors and whether this is adequatelyaddressed, for example by fencing and warning signs.The physical risk associated with topography, e.g. land slide with release of tars,potential for breach of a bund wall.The chemical risk to visitors/trespassers/fauna and flora associated with the high acidityof acid tars and also toxicity c<strong>on</strong>siderati<strong>on</strong>s.The potential for release of toxic gases (especially sulphur dioxide, but also hydrogensulphide), vapours (especially BTEX compounds) and dusts, and the associatedinhalati<strong>on</strong> risks.Factors that influence the risk to c<strong>on</strong>trolled waters, including solubility of tars, mobilityof free phase oils and tars and degradati<strong>on</strong> potential in the unsaturated z<strong>on</strong>e and inpolluted groundwater.The fire risk (including starting of a fire by trespassers/visitors) and build up ofpotentially explosive c<strong>on</strong>centrati<strong>on</strong>s of flammable gases in buildings.The uncertainties associated with variability within the lago<strong>on</strong> and also any wastes ofquite different origin that may have been disposed of with the acid tars.The potential for gas generati<strong>on</strong> and migrati<strong>on</strong> (taking account also of any co-disposalof domestic wastes).Effect of pH <strong>on</strong> the envir<strong>on</strong>mental behaviour of c<strong>on</strong>taminants (e.g. increased metalmobility, interacti<strong>on</strong> with natural minerals).R&D <str<strong>on</strong>g>Technical</str<strong>on</strong>g> Report P5-042/TR/04 32
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