Land Contamination Management & Site Remediation

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  • 1. Land Contamination Management & Site Remediation By :: By Mr Manas Orpe Mr Manas Orpe (BE Chemical Engineering) (BE Chemical Engineering)Under the supervision of: Under the supervision of: Prof K N Bawankar Prof K N Bawankar Department of Chemical Engineering, Department of Chemical Engineering, AISSMS College of Engineering, Pune-1 AISSMS College of Engineering, Pune-1 16/10/131

2. Contents 16/10/13Pollution and Contamination Land Contamination Health Effects Site Remediation Steps Risk Assessment Options Appraisal Verification Plans Implementation of Strategy Remediation Technologies PIL Conclusions References 2 3. Pollution and Contamination In short, there is very little difference between Pollution and Contamination, especially in environmental terms. Pollution can be considered to be something which is not welcomed in the environment. Contamination is more often used to refer to a substance which has been introduced to another substance, generally giving an adverse affect. Pollution clean-up / remediation of soils or water would involve exactly the same actions as Contamination clean-up / remediation. 16/10/133 4. Land Contamination Defined as the introduction of a substance into the land so that its quality and function are adversely affected.16/10/134 5. Health Effects Chronic exposure to chromium, lead and other metals, petroleum, solvents, and many pesticide and herbicide formulations can be carcinogenic. Chronic exposure to benzene at sufficient concentrations is known to be associated with higher incidence of leukemia. Organophosphates and carbomates can induce a chain of responses leading to neuromuscular blockage. Mercury linked to higher incidences of kidney damage. 16/10/135 6. Site Remediation Steps16/10/136 7. Risk Assessment The purpose of preliminary risk assessment is to develop an initial conceptual model of the site and establish whether or not there are potentially unacceptable risks. Information collection may include: i. Desk study ii. Site reconnaissance iii. Additional desk study and exploratory site investigation 16/10/137 8. Options Appraisal A feasible remediation option is one that is likely to meet defined, site-specific objectives relating to both the pollutant linkage and the wider management context for the site as a whole. The purpose of this stage of options appraisal is to develop a remediation strategy capable of practical implementation on the site and to describe in broad terms the characteristics of that strategy. 16/10/138 9. Verification Plan It is a document that gives requirements for gathering data to demonstrate that remediation meets the remediation objectives and remediation criteria. It includes sampling and testing criteria( eg. field monitoring data, analytical data, level surveys above and below capping layers). 16/10/139 10. Implementation Of The Remediation Strategy Dealswithallaspectsofthedesign,preparation,implementation, verification, and long-term monitoring and maintenance of remediation. Elements of design are passed onto the specialist subconsultants or contractors, the design needs to also be subject to proper checking and quality assurance procedures. 16/10/1310 11. Remediation Technologies Remediation technologies are many and varied but can be categorized into ex-situ and in-situ methods. The more traditional remediation approach consists primarily of soil excavation(disposal to landfill dig and dump) and groundwater(pump and treat).16/10/1311 12. Excavation or dredging Excavation processescanbeassimpleashaulingthe contaminated soil to a regulated landfill.16/10/13Fig. 1 Excavated Area12 13. SEARsurfactant enhanced aquifer remediation Also known as Solubilization and recovery, the Surfactant Enhanced Aquifer Remediation process involves the injection of hydrocarbon mitigation agents into the subsurface. In geological formations that allow delivery of hydrocarbon mitigation agents, this approach provides a cost effective and permanent solution. 16/10/1313 14. Contd. This technology is also successful when utilized as the initial step in a multi faceted remedial approach.16/10/1314 15. Solidification and Stabilization Stabilization - involves the addition of reagents to a contaminated material (e.g. soil or sludge) to produce more chemically stable constituents. Solidification - involves addition of reagents to impart stability to contain contaminants in a solid product and reduce access by external agents (e.g. air, rainfall).16/10/1315 16. However, the uptake of S/S technology has been relatively modest, and a number of barriers have been identified including: the lack of authoritative technical guidance on S/S; uncertainty over the durability and rate of contaminant release from S/S-treated material; experiences of past poor practice in the application of cement stabilization processes used in waste disposal in the 1980s and 1990s; and residual liability associated with immobilized contaminants remaining on-site, rather than their removal or destruction. 16/10/1316 17. 16/10/13Fig. 2 Solidification and Stabilization17 18. Pump and Treat Pumpandtreat involvespumpingoutcontaminatedgroundwater with the use of a submersible or vacuum pump and then treating it. Forpetroleum-contaminatedsitesthismaterialisusually activated carbon in granular form.16/10/1318 19. It is expensive and a very slow process. Other methods include trying to increase the dissolved oxygen content of the groundwater to support microbial degradation of the compound.16/10/13Fig. 3 Pump and treat19 20. Soil vapor extraction SVE utilizes different technologies to treat the off-gas volatile organic compounds (VOCs) generated after vacuum removal of air and vapors (and VOCs) from the subsurface. Carbon is used for low (4,000 ppm) VOC concentration. 16/10/1320 21. Vapour condensation involves cryogenically cooling the vapor stream to below 40 degrees C such that the VOCs condensate out of the vapor stream and into liquid form where it is collected in steel containers. This recovered chemical can then be reused or recycled in a more environmentally sustainable or green manner. This technology is also known as cryogenic cooling and compression (C3-Technology). 16/10/1321 22. 16/10/13Fig. 4 Soil Vapour Extraction Technique22 23. Public Interest Litigation Riverine pollution by tanneries, industrial effluents, and untreated sewage; Soil and groundwater pollution; Indiscriminate mining; Protection of forests; Fencing of parks and sanctuaries; Preservation of monuments of archaeological and historical significance and their protection from vandalism; and Automobile pollution. 16/10/1323 24. Fines and Closure Notices Examples :Manufacturer of potassium and sodium bichromate (Gujarat) Dyeing units located in Tirupur, Tamil Nadu Steel manufacturing facility, Kalmeshwar, Maharastra Manufacturing facility located in Aurangabad16/10/1324 25. Conclusions Despite the absence of a concise regulatory framework to deal with polluted sites in India, PILs have given the judiciary enormous scope for intervening in environmental matters and passing severe penalties against companies that have been found guilty. As for the technologies for remediation, they are expensive but need to be done for the environmental health and safety. 16/10/1325 26. References 1. Mary Harris, Judith Lowe, Phil Crowcroft & Casella Stanger, Contaminated land report, Model Procedures for Management of Land Contamination, 2008 2. The Water Act (Prevention and Control of Pollution) 1974 3. Hazardous Wastes (Management & Handling) Amendment Rules, 2003 4. Ravi Costa and Sanjay Sampath, India: Environmental Liability and Contamination Regulations, EHS Journal, 2011 5. Snyder C., "The dirty work of promoting "recycling" of America's sewage sludge, Int J Occup Environ Health, Issue(4)(2005), 415427 16/10/1326 27. THANK YOU16/10/1327