12 - Current Practices in Hazardous Waste Treatment and Disposal

Abstract

The final stages of the hazardous waste management sequence include the treatment and disposal steps, which are complex and technologically demanding. The purpose of hazardous waste treatment and disposal is to mitigate the characteristics that make this waste hazardous and to permanently contain the wastes. This chapter discusses the newer and cleaner technologies being practiced in hazardous waste treatment and disposal that have replaced the outdated strategies in place. Deepwell or underground injection, aqueous organic treatment, incineration, and landfill and surface impoundments are the common hazardous waste management techniques being used. In a deepwell injection system, hazardous wastes in liquid form are injected several thousand feet below the surface through a reinforced well shaft into porous injection zones that are confined by impermeable rock layers. Aqueous organic treatment refers to treatments done to liquid hazardous wastes to reduce their toxicity, ignitability, corrosivity, or reactivity. Incineration is used for hazardous wastes that cannot be reused or recycled and cannot be disposed of safely in a landfill because of excessive toxicity or risk of infectious transmission. Human health effects of land disposal are discussed, which include birth weight effects, congenital defects, respiratory diseases, and social inequity.