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
- Municipal Solid Waste (MSW):
- Hazardous waste- is a waste with properties that make it dangerous or potentially harmful to human health or the environment
- Ignitability- Ignitable waste creates fires under certain conditions or are spontaneously combustible, or have a flash point less than 60 C (140 F)
- Corrosivity- Corrosive waste 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 injected or absorbed.
- Major types: Organic and Heavy Metals, Radioactive wastes
- 4.6% of world population
- 50% of toxic wastes
- 1/3rd of solid waste
- Mining (76%) agricultural (13%), industrial (9.5%)= 98.5%
- Municipal solid waste- 1.5%
- on site (at home)
- open dump
- sanitary landfill
- incineration
- open dumping
- 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
- 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: waste piling up over 150 millions tons/year;
- # of landfills down from 8000 (1988) to 3091(1996)
- methane production
- 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
- solves space problem but:
- produces toxic gases like CI, HCI, HCN, SO2
- High temp furnaces break down hazardous compounds but are expensive
- Burning trash to get the energy or get the profit
- out of sight, free of emission control norms
- contributes to ocean pollution
- can wash back on beaches and can cause death of marine animals
- preferred method: incineration in open sea
- Ocean Dumping 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
- 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
- Junked cars: 150- 200 KG of plastics: soon to be recycled
- USA recycled 83 million tons of MSW
solid waste guided notes
NON RENEWABLE RESOURCES
RESOURCES
- TRADITIONAL ENERGY
- Wood
- field crops
- fecal material
- peat
- CONVENTIONAL ENERGY
- coal
- oil
- natural gas
- nuclear
- WHAT IS PEAT?
- Peat is an accumulation of partially decayed vegetation matter and is the first stage in the formation of coal
- Peat forms in wetland, variously called bogs, moors, muskegs, pocosins, mires, and swamps
- It contains a large amount of water and must be dried
- Mined as a fuel in Ireland and England
- The peat is stacked to slowly to dry out
- ADVANTAGES AND DISADVANTAGES OF OIL
- Conventional oil is currently abundant, has a high net energy yield, and relatively inexpensive, but using it causes air and water pollution and releases greenhouse gases
- Advantages- ample supply us for 42-93 years
- Low cost
- High net energy yield- how much we put in to extract it
- Easily transported within and between countries
- Low land use
- Technology is well developed
- Efficient distribution system
- Disadvantages- needs to find substitutes within 50n years
- Large government subsidies
- Environmental costs not included in market price
- Artificially low price encourages waste and discourages search for alternatives
- Pollutes air when produced and burned
- Releases CO2 when burned
- Can cause water pollution
- OPEC controls most of the world’s oil supplies
- USA produces 9% of the world oil
- USA imports 60% of its oil
- Oil shale is a rock that has dark lines that includes oil in those lines
- ADVANTAGES AND DISADVANATGES OF NATURAL GAS
- Is more plentiful than oil, has a high net energy yield and a fairly low cost, and has the lowest environmental impact on fossil fuels
- Advantages- ample supplies
- High net energy yield
- Low cost
- Less air pollution than other fossil fuels
- Lower CO2 emissions than other fossil fuels
- Easily transported by pipeline
- Low land use
- Good fuel for fuel cells, gas turbines, and motor vehicles
- Disadvantages- nonrenewable resource
- releases CO2 when burned
- Government subsidies
- Environmental costs not included in market price
- Methane (a greenhouse gas) can leak from pipelines
- Difficult to transfer from one country to another
- Can be shipped across ocean on as highly explosive LNG
- What is hydraulic fracturing?
- Or fracking, is a technology used in drilling for oil and natural gas
- ADVANTAGES AND DISADVANTAGES OF COAL
- Advantages-
- very plentiful 225-900 years
- High net energy
- Low cost
- Well developed technology
- Air pollution can be reduced with improved technology
- Disadvantages-
- Severe land disturbance, air pollution, and water pollution
- Severe threat to human health when burned
- Environmental costs not included in market price
- Large government subsidies
- High CO2 emissions when produced and burned
- Radioactive and toxic mercury emissions
- Advantages-
- ADVANTAGES AND DISADVANTAGES OF NUCLEAR ENERGY
- Advantages-
- Large fuel supply
- Low environmental impact
- Emits 1/6 as much CO2 as coal
- Moderate land disturbance and water pollution (without accidents)
- Moderate land use
- Low risks of accidents because of multiple safety systems (except for Chernobyl-type reactors)
- Disadvantages-
- Cannot compete economically without huge government subsidies
- Low net energy yields
- High environmental impact (with major accidents)
- Environmental cost not included in market price
- Risk of castrophic accidents
- No widely accepted solution fro long-term storage for radioactive waste
- Subject to terrorist attacks
- Spreads knowledge and technology for building nuclear weapons
- Advantages-