• Solidification / stabilization and containment of arsenic bearing hazardous wastes The National Environmental Engineering Research Institute (NEERI), Nagpur is undertaking studies related to assessment, remediation and management of hazardous wastes for various industries. Recently, the Institute transferred the technology on "solidification / stabilization and containment of arsenic bearing hazardous wastes" to Zuari Industries Ltd. (ZIL), Goa. NEERI achieved in immobilizing arsenic bearing hazardous waste at the ZIL about 50 metric tons of solid and 250m3 of liquid waste containing around 10 percent of arsenic and disposing them after solidification and stabilization in a secured landfill specially designed and constructed in ZIL site. This entire project in the field of hazardous waste management was handled by NEERI, including development of lab scale protocol for solidification and stabilization, design of the landfill, supervision of the construction of the landfill, implementation of the protocol in the plant and final closure of the landfill.

• Advances in encapsulation technologies for the management of mercury-contaminated hazardous wastes

  Although industrial and commercial uses of mercury have been curtailed in recent times, there is a demonstrated need for the development of reliable hazardous waste management techniques because of historic operations that have led to significant contamination and ongoing hazardous waste generation. This study was performed to evaluate whether the USEPA could propose treatment and disposal alternatives to the current land disposal restriction (LDR) treatment standards for mercury. The focus of this article is on the current state of encapsulation technologies that can be used to immobilize elemental mercury, mercury-contaminated debris, and other mercury-contaminated wastes, soils, sediments, or sludges. The range of encapsulation materials used in bench-scale, pilot-scale, and full-scale applications for mercury-contaminated wastes are summarized. Several studies have been completed regarding the application of sulfur polymer stabilization / solidification, chemically bonded phosphate ceramic encapsulation, and polyethylene encapsulation. Other materials reported in the literature as under development for encapsulation use include asphalt, polyester resins, synthetic elastomers, polysiloxane, sol-gels, DolocreteTM, and carbon/cement mixtures. The primary objective of these encapsulation methods is to physically immobilize the wastes to prevent contact with leaching agents such as water. However, when used for mercury-contaminated wastes, several of these methods require a pretreatment or stabilization step.

  (www.sciencedirect.com)

• Trials on sludge of lime treated spent liquor of pickling unit for use in the cement concrete and its leaching characteristics

  Disposal of sludge of lime treated spent liquor pickling unit, as per the Act of Hazardous Waste (Management and Handling) Rules, 1989 is not easy. Its transportation and construction of lined disposal sites pose very severe problem. In the normal practice, sludge is being disposed of on sides of roads and railway tracks to generally fill the low-lying areas. This may cause severe health hazards. An attempt has therefore been made to utilize the treated spent liquor sludge in cement concrete. Design mix M20 has been prepared with varying concentration of sludge in the laboratory. Toxicity characteristics leaching procedure (TCLP) test as per USEPA has been carried out on cement concrete cubes.

  (www.sciencedirect.com)