OVERVIEW

Solid waste management continues to progress from conventional collection techniques and disposal methods to an integrated approach focused on source reduction and recycling. As land becomes more limited and regulations increase, the environmental engineer also directs attention to development and application of advanced disposal technologies.

Solid wastes are those materials, other than liquids or gases, that are deemed by their owner to no longer possess value and are discarded. They are generated by almost every activity, and the amount varies by source, season, geography, and time.

Historically, solid waste disposal consisted of open dumping but now is carried out in double-lined landfills with collection of and controls for gases and/or leachate. Other disposal means include composting and various incineration processes, which also may be used for codisposal of wastewater treatment sludges. These disposal means typically require controls for created pollutants, such as leachate and odor from compost operations and chemical and particulate emission from incinerator combustion.

Recovery and reuse are practiced widely. Source or central facility separation is used for a variety of products including paper, glass, plastics, ferrous metals, and nonferrous metals. Also, refuse-derived fuels may be used for energy production, and yard wastes may be composted to produce a humus soil conditioner.