ENV200 Chapter 14 Notes

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School of Environment
Romila Verma

CHAPTER 14 – SOLID AND HAZARDOUS WASTE [14.2] WASTE DISPOSAL METHODS Open dumps release hazardous substances into the air and water ­ Open, unregulated dumps o Predominant method of waste disposal in most developing countries, because government infrastructure has difficulty serving growing populations o Giant megacities in the developing world have enormous garbage problems o Most developed countries forbid open dumping, but illegal dumping is a problem  Washes into sewers and then into the ocean  Pollutes large quantities of drinking or irrigation water Ocean dumping is mostly uncontrolled ­ Oceans are not large enough to absorb our waste without harm ­ Plastic debris is a growing problem in all the world's oceans o Carelessly discarded litter and uncontained garbage o Deliberate disposal, especially from cruise ships and container ships ­ Great Pacific Garbage Patch = the best-known plastic debris field o Gyres that are driven by the earth’s rotation collect floating plastic debris ­ Plastic debris outweighs living biomass in the Pacific and Atlantic oceans o Fish and seabirds have been found with stomachs full of plastic fragments o Plastic is slowly starving ocean ecosystems Landfills receive most of our waste ­ Sanitary landfill = the refuse is compacted and covered with a layer of dirt every day (e.g., dirtfill) + clay layer and/or plastic liner + drainage system o Decrease smells and litter o Discourage insects and rats o Helps control pollution o Takes up more landfill space o Impermeable clay layer and/or plastic liner prevent leakage to groundwater and streams o Drainage systems are installed in and around the liner to catch drainage and to help monitor chemicals that leak out o Must manage methane  Methane = a greenhouse gas produced when organic material decomposes in the anaerobic conditions deep inside a landfill  More potent at absorbing heat than CO2  Landfills are the single largest anthropogenic source of methane  Landfill gas is either burned on site or is collected and used as fuel to generate electricity ­ Historically, landfills were convenient and cheap o Less waste to deal with o Few regulations about disposal sites and methods ­ With new rules for public health protection, landfills are becoming fewer, larger, and more expensive o Rising landfill costs make it more economical to pursue alternatives strategies (e.g., waste reduction, recycling) We often export waste to countries ill-equipped to handle it ­ Most industrialized nations still ship hazardous and toxic waste to less-developed countries o Black sludge = petroleum wastes containing hydrogen sulfide and volatile hydrocarbons ­ Most of the world's obsolete ships are dismantled and recycled in poor countries o Old ships are full of toxic and hazardous materials (e.g., oil, diesel fuel, asbestos, heavy metals) ­ E-waste = discarded electronics o One of the greatest sources of toxic material currently going to developing countries  Some components are recycled  Most components go to open dumps or landfills o Contains heavy metals and valuable metals ­ Most e-waste used to be shipped to China o Health risks in this work are severe o Soil, groundwater, and surface-water contamination at these sites are extremely high o Shipping e-waste to China is now officially banned, but illegal smuggling continues ­ Informal e-waste recycling has shifted to areas with weak environmental regulation ­ Production of e-waste is increasing in both developed and developing areas, but most e-waste will be produced in developing areas ­ Basel Action Network = an international network of activists seeking better controls on global trade in toxic materials Incineration produces energy from trash ­ Many cities have built waste incinerators to burn municipal waste o Reduces the volume of waste o Residual ash and un-burnable residues are disposed in landfills o Reduces landfilling costs o Energy recovery (e.g., waste-to-energy) = using the heat derived from incinerated refuse to provide heating, to produce steam, and/or to generate electricity o Refuse-derived fuel = refuse is sorted as it comes in to remove un-burnable or recyclable materials before combustion  Enriched burnable fraction has a higher energy content than raw trash o Mass burn = dump everything into a giant furnace, unsorted, and burn as much as possible  Avoids the expensive and unpleasant job of sorting  Produces more unburned ash  Fly ash is more concentrated with toxic materials than heavy bottom ash o Fly ash = lighter, airborne particles, which can penetrate deep into the lungs o Heavy bottom ash = collects inside the burner system  Must remove batteries containing heavy metals and plastics containing chlorine before wastes are burned  Produces more air pollution ­ Cost-effectiveness of garbage incinerators o Initial construction costs are high o Tipping fees at an incinerator are higher than those at a landfill  Tipping fees = the fee charged to haulers for each ton of garbage dumped o Cities usually have contracts guaranteeing certain amounts of waste daily o Produce large amounts of ash and hazardous airborne emissions if not well built and well managed o Modern incinerators are among the smallest sources of hazardous emissions because of tighter permitting processes, better inspections, and high burn temperatures o Separating plastics from other garbage will eliminate nearly all dioxins and furans [14.3] SHRINKING THE WASTE STREAM ­ Recycling = the reprocessing of discarded materials into new products o Saves money, energy, raw materials, and land space o Reduces pollution o Easiest when materials are separated ­ Making recycling pay for itself is often the critical challenge o Some materials are heavy and low-value, so they can be difficult to ship economically to recycling facilities o Aluminum  Lightweight and high-value  Expensive to produce from raw materials  Easiest and most valuable material to recycle, but recycling rate is low ­ Fluctuations in commodity prices are a challenge in developing a market for recycled materials ­ Low prices for new materials is a primary obstacle o Plastic  New plastic (made from oil) is cheaper than used plastic  Contamination is a major obstacle in plastics recycling  PET (polyethylene terephthalate) can be remanufactured  Any trace of PVC (polyvinyl chloride) can make PET useless ­ Growing popularity of bottled water is a serious waste disposal problem o Recycling rate is low o Oil is used to manufacture and ship the bottles o Tap water is safe and is subjected to more rigorous testing than bottled water o Bottle deposits = bottles are returned and deposits are refunded  Control the problem of water bottle recycling  Prevent the costs of roadside litter Recycling saves money, energy, and space ­ Some recycling programs cover their own expenses with materials sales ­ Other recycling programs have difficulty paying for themselves ­ Recycling is usually cheaper than other disposal methods (e.g., landfilling, incineration), which aren’t expected to pay for themselves o Disposing of waste is more expensive than recycling ­ Recycling lowers demand for raw resources o Recycling newspapers saves trees o Recycling plastic saves petroleum and makes the country less dependent on foreign oil o Recycling aluminum saves bauxite (aluminum ore) and keeps aluminum fluoride out of the air ­ Recycling reduces energy consumption and air pollution Composting recycles organic waste ­ Many cities have banned yard waste from the municipal waste stream ­ Composting = biological degradation or breakdown of organic matter under aerobic conditions o Makes a nutrient-rich soil amendment that aids water retention o Slows soil erosion o Improves crop yields ­ Some composting systems produce methane fuel o Methane is captured at many landfills, but it is more efficient to convert organic waste to methane in an anaerobic digester o Household methane generators (e.g., small scale anaerobic digesters) can provide fuel for cooking and lighting for homes Reuse is even better than recycling ­ Cleaning and reusing materials saves the cost and energy of remaking them into something else ­ Reusable, refillable bottles are the most efficient beverage container o Better for the environment o More profitable for local communities ­ Reusable containers favor local bottling companies and help preserve regional businesses ­ Reusing manufactured goods is common in many less-affluent nations Reducing waste is the cheapest option ­ Reducing the production of throw-away products is the most effective way to save energy, materials, and money ­ The three R’s = reduce, reuse, recycle ­ In recent decades, we have greatly increased our waste production rather than reducing it ­ Excessive packaging of food and consumer products is one of our greatest sources of unnecessary waste o Mostly for mark
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