WHERE IS AWAY?

SOLID WASTE

What is a solid waste?• Any material that we discard, that is not liquid or gas, is solid

waste• Municipal Solid Waste (MSW):

• Solid waste from home or office• Industrial Solid Waste:

• Solid waste produced from Mines, Agriculture or Industry

What is a Hazardous Waste?• Hazardous waste is a waste with properties that make it dangerous or

potentially harmful to human health or the environment• Ignitability - Ignitable wastes create fires under certain conditions or

are spontaneously combustible, or have a flash point less than 60 °C (140 °F).

• Corrosivity - Corrosive wastes are acids or bases (pH less than or equal to 2 or greater than or equal to 12.5) that are capable of corroding metal containers, such as storage tanks, drums, and barrels.

• Reactivity - Reactive wastes are unstable under "normal" conditions. They can cause explosions, toxic fumes, gases, or vapors when mixed with water.

• Toxicity - Toxic wastes are harmful or fatal when ingested or absorbed (e.g., containing mercury, lead, etc.). When toxic wastes are disposed of on land, contaminated liquid may drain (leach) from the waste and pollute ground water. Toxicity is defined through a laboratory procedure called the Toxicity Characteristic Leaching Procedure (TCLP).

• Major types: Organics and Heavy Metals, Radioactive wastes

U.S. Scenario• 4.6% of world population• 50% of toxic wastes• 1/3rd of solid wastes• Mining (76%), agricultural (13%), industrial (9.5%) = 98.5%• Municipal solid waste – 1.5%

Municipal Solid Waste (MSW)

Waste Management

What are Methods of Dealing with Municipal Waste?• On-site (at home)• Open Dump• Sanitary Landfill• Incineration• Ocean dumping

Open Dump

• Unsanitary, draws pests and vermin, harmful runoff and leachates, toxic gases

• Still accounts for half of solid waste • Several thousand open dumps in the USA

Sanitary Landfill• Sanitary Landfill

• Layer of compacted trash covered with a layer of earth once a day and a thicker layer when the site is full

• Require impermeable barriers to stop escape of leachates: can cause problem by overflow

• Gases produced by decomposing garbage needs venting

• 1 acre/10,000 people: acute space problem: wastes piling up over 150 million tons/year;

• # of landfills down from 8000(1988) to 3091(1996)• Methane Production

Sanitary Landfill• Avoid:

• Swampy area/ Flood plains /coastal areas• Fractures or porous rocks• High water table

• Prefer:• Clay layers• Heads of gullies

Monitoring of Sanitary Landfills• Gases: Methane, Ammonia, Hydrogen sulphide

• Heavy Metals: Lead, Chromium in soil• Soluble substances: chloride, nitrate, sulfate• Surface Run-offs• Vegetation: may pick up toxic substances• Plant residue in soil• Paper/plastics etc – blown by the wind

Incineration• Solves space problem but:

• produces toxic gases like Cl, HCl, HCN, SO2• High temp furnaces break down hazardous compounds but are expensive ($75 - $2K/ton)

• Heat generated can be recovered: % of waste burnt• Japan 67%, Switzerland 80%, USA 6%

• North Little Rock, AK saving $50K in heating cost and reducing landfill requirement by 95%

• How many MSW combustors exist in the United States? In 1996, 110 combustors with energy recovery existed with the capacity to burn up to 100,000 tons of MSW per day.

Ocean Dumping• Out of sight, free of emission control norms• Contributes to ocean pollution• Can wash back on beaches, and can cause death of marine mammals

• Preferred method: incineration in open sea• Ocean Dumping Ban Act, 1988: bans dumping of sewage sludge and industrial waste

• Dredge spoils still dumped in oceans, can cause habitat destruction and export of fluvial pollutants

Reducing Waste• Incineration, compacting• Hog feed: requires heat treatment• Composting: requires separation of organics from glass and metals

• Recycling and Reusing• Recycle of glass containers: 5 million tons• Plastic: marked by types for easy recycling• Converted into Fibers, trash bags, plastic lumber, fill for

pillows, insulation etc• Junked cars: 150 – 200 kg of plastics: soon to be recycled

What are the Benefits of Recycling?• USA recycled 83 million tons of MSW. • This provides an annual benefit of 182 million metric tons of

carbon dioxide equivalent emissions reduced, • comparable to removing the emissions from 33 million

passenger cars. • But the ultimate benefits from recycling are cleaner land, air,

and water, overall better health, and a more sustainable economy.

Auto batteries: 99.2%Office Type Papers: 70.9%Yard Trimmings: 64.7%Steel Cans: 62.8%

Aluminum Beer and Soft Drink Cans: 48.2%Tires: 35.4%HDPE Natural (White Translucent) Bottles: 29.3%Glass Containers: 28.0% PET Bottles and Jars: 27.2%

Recycling in USA

•In 1996, recycling of solid waste in the United States prevented the release of 33 million tons of carbon into the air—roughly the amount emitted annually by 25 million cars.

•1 ton of newspaper=18 trees, 3 m3 of landfill, 60% less energy. Govt recycling saving 223,000 tons, 4 million trees, $7.4 million

Auto Steel Aluminum Paper & Yard Glass Plastic Tires Batteries Cans Packaging Paperboard waste container container

http://www.epa.gov/epawaste/facts-text.htm

Recycling: facts and figures• In 1999, recycling and composting activities prevented about 64 million tons of material from ending up in landfills and incinerators. Today, this country recycles 32 percent of its waste, a rate that has almost doubled during the past 15 years.• 50 percent of all paper, 34 percent of all plastic soft drink bottles, 45 percent of all aluminum beer and soft drink cans, 63 percent of all steel packaging, and 67 percent of all major appliances are now recycled.• Twenty years ago, only one curbside recycling program existed in the United States, which collected several materials at the curb. By 2005, almost 9,000 curbside programs had sprouted up across the nation. As of 2005, about 500 materials recovery facilities had been established to process the collected materials.

What is Liquid Waste?• Sewage• Highly toxic Industrial Waste & Used Oil

• Dilute and Disperse• Concentrate and Contain• Secure Landfill

• Sealed drums to be put in impermeable holds with monitoring wells to check for leakage: does not work

• Deep well Disposal• Pumping in deep porous layer bounded by impermeable

formations, well below water table• $1 million to drill, $15-20/ton afterwards• Restricted by geological considerations, can trigger

earthquakes