Evolution of Waste Disposal and Management

1. Chapter 29: Treating Wastes

2. Early Concepts of Waste Disposal • Start of Industrial Revolution, the volume of waste produced in the US was relatively small. • Managed through the concept of “dilute and disperse.” • Factories located near water. • Easy transport of materials by boat • Sufficient water for processing and cooling • Easy disposal of waste into the river • Few factories and a sparse population • Method was sufficient to remove the waste from the immediate environment.

3. Early Concepts of Waste Disposal • As industrial and urban areas expanded, the concept became “concentrate and contain” • Containment not always achieved. • Containers leak or break and allow waste to escape. • People are facing a serious solid-waste disposal problem. • We are producing a great deal of waste and the acceptable space for permanent disposal is limited. • Difficult to site new landfills (NIMBY).

4. Modern Trends • Environmentally correct concept is to consider wastes as resources out of place. • Waste would be a resource to be used again. • Referred to as the “zero waste” movement. • Industrial ecology • Study of relationships among industrial systems and their links to natural systems. • Waste from one part of the system would be a resource for another part.

5. Modern Trends • Countries have moved to cut waste by imposing taxes. • Taxation of waste in all its various forms, from emissions from smokestacks to solids delivered to landfills. • As taxes increase people produce less waste. • Landfills produce methane gas which can be burned as fuel.

8. Integrated Waste Management • A set of management alternatives that includes: • Reuse • Source reduction • Recycling • Composting • Landfill • Incineration

9. Reduce, Reuse, Recycle • Ultimate objective of the three R’s is to reduce. • Study of the waste stream in areas that utilize IWM technology suggests that the amount of refuse disposed of in landfills or incinerated can be reduced by at least 50% • Reduction facilitated by • Better design of packaging to reduce waste, an element of source reduction (10% reduction). • Large-scale composting programs (10% reduction). • Establishment of recycling programs (30% reduction).

10. Reduce, Reuse, Recycle • Recycling is a major player in the reduction of urban waste stream. • Estimated that as much as 80-90% of the US waste stream might be recovered through intense recycling. • Partial recycling can provide a significant reduction ~50%. • Simplified by single stream recycling.

12. Public Support for Recycling • Encouraging signs • An increase in the willingness of industry and business to support recycling on a variety of scales. • People are now more likely to purchase products that can be recycled or that come in containers that are more easily recycled or composted.

13. Markets for Recycled Products • In communities where recycling has been successfully implemented, it has resulted in glutted markets for the recycled products. • If recycling is to be successful, • markets and processing facilities will also have to be developed to ensure that recycling is a sound financial venture.

14. Recycling of Human Waste • The use of human waste or “night soil” on croplands is an ancient practice. • Early uses of human waste for agriculture occasionally spread infectious diseases. • One of the major problems of recycling human waste today is that thousands of chemicals and metals flow through our waste stream. • Because many toxic materials are likely to be present with the waste, we must be very skeptical of utilizing sewage sludge for land application.

15. Materials Management • Futuristic waste management has the goal of zero production of waste. • Consistent with the ideals of industrial ecology. • Goal will require more sustainable use of materials combined with resource conservation in what is being termed materials management.

16. Materials Management • The goal could be pursued in the following ways: • Eliminate subsidies for extraction of virgin materials. • Establish “green building” incentives that encourage the use of recycled-content materials and products in new construction. • Assess financial penalties for production that uses negative materials management practices.

17. Materials Management • Provide financial incentives for industrial practices and products that benefit the environment by enhancing sustainability. • Increase the number of new jobs in the technology of reuse and recycling of resources.

18. Solid-Waste Management • Continues to be a problem in many parts of the world. • Many practices inadequate. • Open dumps, illegal roadside dumping • Social problem as much as a physical one, because many people are simply disposing of their waste as inexpensively and as quickly as possible.

19. Composition of Solid Waste • Paper is by far the most abundant content. • Excavations into modern landfills using archeological tools have cleared up some misconceptions concerning other items. • Fast-food packaging accounts for about 0.25% of the average landfill • Disposable diapers, approximately 0.8% • Polystyrene products, about 0.9%

21. On-Site Disposal • A common on-site disposal method in urban areas is the mechanical grinding of kitchen food waste. • Garbage-disposal devices are installed at the kitchen sink, and the garbage is ground and flushed into the sewer system.

22. Composting • Biochemical process in which organic materials decompose to a rich, soil-like material. • The process involves rapid partial decomposition of moist solid organic waste by aerobic organisms. • As a waste management option, large-scale composting is generally carried out in the controlled environment of mechanical digesters.

23. Incineration • Combustible waste is burned at temperatures high enough (900°–1,000°C, or 1,650°–1,830°F) to consume all combustible material. • Leaving only ash and non-combustibles to dispose of in a landfill. • Process of incineration can be used to supplement other fuels and generate electrical power. • In modern incineration facilities, smokestacks are fitted with special devices to trap pollutants.

24. Open Dumps • In the past, solid waste was often disposed of in open dumps, where the refuse was piled up without being covered or otherwise protected. • Located wherever land is available, without regard to safety, health hazards, or aesthetic degradation. • Common sites • Abandoned mines and quarries, natural low areas, such as swamps or floodplains; and hillside areas above or below towns.

26. Sanitary Landfills • Designed to concentrate and contain refuse w/o creating a nuisance or hazard to public health or safety. • Confined to the smallest practical area • Reduced to the smallest practical volume • Covered with a layer of compacted soil at the end of each day of operation.

27. Leachate • The most significant hazard from a sanitary landfill is pollution of groundwater or surface water. • If waste comes into contact with water, leachate is produced. • noxious, mineralized liquid capable of transporting bacterial pollutants

28. Site Selection • A number of factors must be taken into consideration when selecting a site, including: • Topography • Location of the groundwater table • Amount of precipitation • Type of soil and rock • Location of the disposal zone in the surface water and groundwater flow system. • Best sites are arid sites

29. Site Selection • The waste is buried above the water table in relatively impermeable clay and silt soils. • Leachate produced remains in the vicinity of the site and degrades by natural filtering action. • Site selection also involves important social considerations. • Chosen where they expect local resistance to be minimal or where they perceive land to have little value. • Frequently located in areas of low socioeconomic status

31. Monitoring Pollution in Sanitary Landfills • Once a site is chosen for a sanitary landfill and before filling starts, monitoring the movement of groundwater should begin. • Accomplished by periodically taking samples of water and gas from specially designed monitoring wells. • Monitoring the movement of leachate and gases should continue as long as there is any possibility of pollution.

32. 1. Methane, ammonia, hydrogen sulfide, and nitrogen gases can be produced from compounds in the soil and the waste and can enter the atmosphere. 2. Heavy metals, such as lead, chromium, and iron, can be retained in the soil. How Pollutants Can Enter the Environment from Sanitary Landfills

33. How Pollutants Can Enter the Environment from Sanitary Landfills 3. Soluble materials, such as chloride, nitrate, and sulfate, can readily pass through the waste and soil to the groundwater system. 4. Overland runoff can pick up leachate and transport it into streams and rivers.

34. How Pollutants Can Enter the Environment from Sanitary Landfills 5. Plants growing in the disposal area can selectively take up heavy metals and other toxic materials. Passed up the food chain as people and animals eat the plants. 6. If plant residue return toxic substances to the soil.

35. How Pollutants Can Enter the Environment from Sanitary Landfills 7. Streams and rivers may become contaminated by waste from groundwater seeping into the channel (3) or by surface runoff (4). 8. Toxic materials can be transported to other areas by the wind.

36. How Pollutants Can Enter the Environment from Sanitary Landfills • Modern sanitary landfills are engineered to include multiple barriers: • Clay and plastic liners to limit the movement of leachate • Surface and subsurface drainage to collect leachate • Systems to collect methane gas • Groundwater monitoring to detect leaks of leachate below and adjacent to the landfill.

39. Federal Legislation for Sanitary Landfills • Resource Conservation and Recovery Act of 1980. • Legislation intended to strengthen and standardize design, operation, and monitoring of sanitary landfills. • Landfills that cannot comply with regulations face closure. • States may choose between two options: • 1. Comply with federal standards. • 2. Seek EPA approval of solid-waste management plans, which allows greater flexibility.

40. Federal Legislation for Sanitary Landfills • Provisions of federal standards include the following: • Landfills may not be sited on floodplains, wetlands, earthquake zones, unstable land, or near airports. • Landfills must have liners. • Landfills must have a leachate collection system. • Landfill operators must monitor groundwater for many specified toxic chemicals. • Landfill operators must meet financial assurance criteria to ensure that monitoring continues for 30 years after the landfill is closed.

41. Federal Legislation for Sanitary Landfills • EPA approval of its landfill program: • Groundwater monitoring may be suspended. • Alternative types of daily cover over the waste. • Alternative groundwater protection standards and schedules for documentation are allowed. • Under certain circumstances, landfills in wetlands and fault zones are allowed. • Alternative financial assurance mechanisms are allowed.

42. Reducing the Waste You Produce

43. Hazardous Waste • In the US, approximately 1,000 new chemicals are marketed each year, and about 70,000 chemicals are currently on the market. • 35,000 chemicals used are classified as definitely or potentially hazardous to the health of people or ecosystems. • The US currently produces about 700 million metric tons of hazardous chemical waste per year, referred to more commonly as hazardous waste.

44. Hazardous Waste • Uncontrolled dumping of chemical waste has polluted soil and groundwater in several ways: • Chemical waste may be stored in barrels.The barrels eventually corrode and leak. • When liquid chemical waste is dumped into an unlined lagoon, contaminated water may percolate through soil and rock to the groundwater table. • Liquid chemical waste may be illegally dumped in deserted fields or even along roads.

47. Resource Conservation and Recovery act • Passed in 1976 • Identification of hazardous wastes and their life cycles. • “Cradle to grave” management • The act classifies hazardous wastes in several categories: • Materials highly toxic to people and other living things; • Wastes that may ignite when exposed to air; • Extremely corrosive wastes • Reactive unstable wastes that are explosive or generate toxic gases or fumes when mixed with water.

48. Comprehensive Environmental Response, Compensation, and Liability Act • Passed in 1980 • Act defined policies and procedures for release of hazardous substances into the environment. • Mandated development of a list of the sites where hazardous substances were likely to or already had produced the most serious environmental problems • Established a revolving fund (Superfund) to clean up the worst abandoned hazardous-waste sites.

49. Comprehensive Environmental Response, Compensation, and Liability Act • Strengthened by amendments that made the following changes: • Improved and tightened standards for disposal and cleanup of hazardous waste. • Banned land disposal of certain hazardous chemicals. • Initiated a timetable for phasing out disposal of all untreated liquid hazardous waste in landfills or surface impoundments. • Increased the size of the Superfund.

50. Hazardous-Waste Management Land Disposal • Management of hazardous chemical waste involves several options, including: • Recycling • On-site processing to recover by-products with commercial value • Microbial breakdown • Chemical stabilization • High-temperature decomposition • Incineration • Disposal by secure landfill or deep-well injection