Chemical fixation and solidification of hazardous wastes

Novel separation methods for removing nanoparticles and copper from chemical mechanical planarization wastes

Contaminated lands are often the blight of concerted industrial activities in highly developed and industrialized countries. Unfortunately, Malaysia is not unaffected by this issue and thus requires intervention in terms of tightening of legislation regarding contaminated land as well as application of established remediation technologies. Since redevelopment of such sites are already earmarked under the 9th Malaysia Plan, it is reckoned that the next step for related stakeholders is to focus on local customization or creation of cost-effective and effectual contaminated land remediation technologies. As applications of these technologies are still in their infancy in Malaysia, familiarity of such technologies is lacking among pertinent stakeholders. Therefore, this paper aims to provide an overview of the types of contaminated land remediation technologies with regards to their current usage and applicability in the Malaysian context. Technologies such as soil vapour extraction, bio-remediation, containment, solidification/ stabilization, excavation and phyto-remediation are described. It is suggested that a long-term strategy be established to ensure more expertise and technologies with regards to contaminated land remediation will be locally available. All agencies, either public or private should invest in the training of their personnel so that a pool of local experts can be made available in the near future.

methods

Contaminated land remediation technologies: current usage and applicability in Malaysia

The effectiveness of ordinary portland cement (OPC) in the immobilization of heavy-metal contaminated soil was investigated in this study. Heavy metal contaminated soil was collected from a scrap metal yard within the outskirts of Kuala Lumpur, Malaysia. Metal composition analysis indicated that the predominant heavy metals present in the soil were iron and aluminium with some composition of zinc and lead and little composition of copper and chromium. The contaminated soil was treated with OPC using cement-to-dry soil (C/S d) ratios of 0.5, 1, 2, 4 and 8. The effectiveness of the treatment was evaluated by performing unconfined compressive strength (UCS) test and crushed block leaching on the treated soil. Crushed block leaching tests were performed in accordance with standard protocols of Method 1311: Toxicity Precipitation Leaching Procedure (TCLP) and Method 1312: Synthetic Precipitation Leaching Procedure (SPLP) of the United States Environmental Protection Agency (USEPA). The treatment results were compared to the solidified waste acceptance criteria which were compiled based on the regulatory waste disposal limit at a disposal site in the United Kingdom (UK) and the maximum concentration of contaminants for toxicity characteristic of solid wastes from USEPA. The UCS values of the solidified samples at 28 days under air drying for C/S d ratios of 0.5 ‐ 8.0, far exceeded the minimum landfill disposal limit of 0.34 N/mm 2 at a disposal site in the UK. Subsequent to leaching of the treated soils by three different leaching solutions (acetic acid, deionized water and nitric/sulfuric acid), metals in the leachates were either undetectable or appreciably below the proposed leachability limits.

background

Remediation of Heavy Metal Contaminated Soil by Using Chemical Stabilization

Efektivní způsoby zneškodňování odpadů se v současné době stávají prioritní otázkou ekonomickou i ekologickou. Používané technologie patří k nejdynamičtěji se rozvíjejícím odvětvím národního hospodářství a vývoj v této oblasti je stimulován zejména stále se zvyšujícími požadavky v oblasti ochrany životního prostředí. Jednou z progresivních metod fyzikálně-chemické úpravy odpadů je jejich stabilizace, která může výrazně přispět k efektivnosti ukládání odpadů na skládky'. Perspektivní se rovněž jeví využití produktů vznikajících při tomto procesu k přípravě různých polotovarů využitelných např. ve stavebnictví.

Chemicka stabilizace nebezpecnych slozek v prumyslovych odpadech

Wastewater at Oak Ridge National Laboratory (ORNL) is collected, evaporated, and stored in the Melton Valley Storage Tanks (MVST) pending treatment for disposal. The waste separates into two phases: sludge and supematant. Some of the supematant from these tanks has been decanted, solidified into a grout, and stored for disposal as a solid low-level waste. The sludges in the tank bottoms have been accumulating ,for several years. Some of the sludges contain a high amount of gamma activity (e.g., `37CS concentration range of 0.01 3-11 MBq/g) and contain enough transuranic (TRU) radioisotopes to be classified as TRU wastes. Some Resource Conservation and Recovery Act (RCRA) metal concentrations are high enough in the available total constituent analysis for the MVST sludge to be classified as RCRA hazardous; therefore, these sludges are presumed to be mixed TRU waste.

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Chemical fixation and solidification of hazardous wastes

Citations

Novel separation methods for removing nanoparticles and copper from chemical mechanical planarization wastes

Contaminated land remediation technologies: current usage and applicability in Malaysia

Remediation of Heavy Metal Contaminated Soil by Using Chemical Stabilization

Chemicka stabilizace nebezpecnych slozek v prumyslovych odpadech

Grout and glass performance in support of stabilization/solidification of ORNL tank sludges

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