Environment in the News
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chapter_16.pptSolid and Hazardous Waste
Chapter 16
Reusing and recycling old automobiles
- 75% of a car’s parts can be recycled or reused
- 25% (glass, metals, plastics, rubber, fabrics, etc.) end up in landfills
- About 37% of the iron and steel scrap reprocessed in US comes form old cars
- Produces 87% less air pollution, 76% less water pollution, than mining and refining an equivalent amount of ore
- Japan, 2015, 95% of cars must be recycled/recovered
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Solid Waste
- Learning Objectives:
Distinguish between municipal and nonmunicipal solid waste
Describe the features of a modern sanitary landfill and relate some of the problems associated with sanitary landfills
Describe the features of a mass burn incinerator and relate some of the problems associated with incinerators
Explain the composting process
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Solid Waste
- US generates more solid waste per capita than any other country = 2.1 kg per day
- Canada is a close second
- Materials that we throw away would be repaired, reused or recycled in less affluent nations
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Solid Waste
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Solid Waste
- Types of Solid Waste
- Municipal Solid Waste
- Combined residential and commercial waste produced by a municipal area - 2% of total waste
- Solid materials discarded by homes, offices, stores, restaurants, schools, hospitals, prisons, libraries, and other commercial and institutional facilities
- Paper and paperboard, yard waste, plastics, food waste, metals, rubber, leather, textiles, wood and glass
- Non-municipal Solid Waste
- Generated by industry, agriculture, and mining
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Solid Waste
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Solid Waste
- Disposal of Solid Waste
- Open Dumps
- Old method, now illegal. Unsanitary, smelly, supported populations of disease-carrying animals (rats, flies, etc)
- Sanitary Landfills
- Waste is compacted and buried under a shallow layer of soil
- Incineration
- Burning of waste. Reduces volume by 90%
- Composting
- Yard and food waste are converted into compost, which has nutritional properties for soil
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Solid Waste
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Solid Waste
- Sanitary Landfills
- Replaced open dumps
- Receive 54% of municipal waste
- Does not pollute local surface or groundwater
- Double-liner system at the bottom of landfill
- Plastic, clay, plastic, clay
- Collect leachate (liquid that seeps through solid waste) and gases produced during decomposition
- Strict guidelines and management, but still problems
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What a Scientist Sees
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Solid Waste
- Special Problem of Plastic
- Amount of plastic in solid waste is growing
- Packaging is about half the amount of plastic
- Chemically stable, doesn’t decompose
- Some areas have banned use of certain plastics
- Alternatives
- Photodegradable
- Degrade when exposed to light-doesn’t work if buried
- Biodegradable
- Decomposed by microorganisms, but preliminary studies show it doesn’t work in landfills
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Solid Waste
- Incineration
- Benefits:
- Volume of solid waste is reduced by 90%
- Produces heat that can be used warm buildings or generate electricity
- Best materials for burning are paper, plastic, rubber
- Glass and food waste must be removed
- Problems:
- Air pollution, CO, particulates, heavy metals, toxic materials
- Large quantities of ash, which require proper disposal in hazardous waste facilities
- Expensive to run due to costly pollution control devices
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Solid Waste
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Solid Waste
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Solid Waste
- Composting
- Yard waste is a substantial portion of municipal solid waste
- Best recovery method is to convert it into soil conditioners, provide nutrients to the soil
- Compost
- Mulch
- Other compostables
- Food scraps, sewage sludge, agricultural manure
- Uses
- Landscaping in public parks and playgrounds
- Sold to gardeners
- First became popular in Europe, now part of integrated waste management in US as well.
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Solid Waste
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EnviroDiscovery
- The US-China Recycling Connection
- In the 2000s, China became biggest importer of America’s recyclable materials “scrap”
- Used in China as raw material for Chinese factories
- China depends on scrap for economic growth
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Global Climate Change
How do municipal and nonmunicipal solid waste differ?
What are some features of sanitary landfills? What problems are associated with them?
What are the main features of a mass burn incinerators? What problems are associated with incinerators?
How do composters work?
Reducing Solid Waste
- Learning Objectives
Define source reduction
Summarize how source reduction, reuse, and recycling help reduce the volume of solid waste
Define integrated waste management
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Reducing Solid Waste
- Goals of Waste Prevention
- Reduce the amount of waste as much as possible
- Purchase products that have less packaging, last longer or are repairable
- Decrease consumption: “Do I REALLY need it?”
- Reuse products as much as possible
- Recycle materials as much as possible
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Reducing Solid Waste
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Reducing Solid Waste
- Source Reduction
- Products are designed and manufactured in ways that decrease the amount of solid and hazardous waste they produce
- Dematerialization- making smaller and more durable products to replace larger more wasteful products
- Reusing Products
- For example, refillable glass beverage bottles, which get reused by bottlers
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Reducing Solid Waste
- Recycling Materials
- Many materials can be collected and processed into new products
- Conserves natural resources, more environmentally benign
- Every ton of recycled paper saves 17 trees, 7000 gallons of water, 4100 kwh of energy and 3 cubic yards of landfill space
- In 2007 annual recycling rate in US was 374 lbs per person
- US recycles about 32% of solid waste
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Reducing Solid Waste
- Recycling Paper
- US currently recycles 55% of paper and paperboard (Denmark, 97%)
- Recycling Glass
- 28% glass waste recycled in US
- Costs less than glass made from virgin materials
- Containers are crushed to make cullet
- New containers are made from cullet
- Different colors are separated before crushing to make cullet more valuable
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Reducing Solid Waste
- Recycling Metals
- Aluminum - best success stories in the US
- 49% of beverage cans are recycled
- Requires less energy to recycle than to make new can from raw materials
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Reducing Solid Waste
- Recycling Plastic
- 12% of containers and packaging in the US
- 37% of recycled plastic is used to make carpet, auto parts, tennis ball felt, polyester cloth
- Depending on economy (price of petroleum), sometimes it’s cheaper to make plastic from raw materials than to recycle
- 46 different plastic types are common, many are mixtures.
- All must be separated before recycling
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Reducing Solid Waste
- Recycling Tires
- Used for retreat tires, playground equipment, trash cans, garden hoses, rubberized asphalt for pavement
- Carpets, roofing materials, molded products
- Lots of research in product development
- Also burned in waste-to-energy incinerators to produce electricity
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Environmental Insight
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Environmental Insight
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Reducing Solid Waste
- Integrated Waste Management
- A combination of the best waste management techniques into a consolidated program to deal effectively with solid waste
- Waste minimization, waste prevention (reduce, reuse, recycle)
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Environmental InSight
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Global Climate Change
What is source reduction?
How do source reduction, reuse, and recycling reduce the volume of solid waste?
What is integrated waste management?
Hazardous Waste
- Learning Objectives:
Define hazardous waste
Briefly characterize two types of hazardous waste: dioxins and PCBs
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Hazardous Waste
- Also called Toxic Waste
- 1% of solid waste stream in US
- Discarded chemical that threatens human health or the environment
- Dangerously reactive, corrosive, ignitable, or toxic chemicals
- Solids, liquids, gases
- 700,000 different chemicals
- Love Canal disaster
- Hooker Chemical Company covered toxic dump with topsoil and donated to school board
- Toxic waste from abandoned dump leaked into neighborhood and contaminated homes and people
- 700 families were evacuated
- Lead to the creation of Superfund Act
- Holds polluters accountable for the cost of cleanup
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Hazardous Waste
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Hazardous Waste
- Types of Hazardous Waste
- Many have been discussed in other chapters
- Dioxins
- Group of 75 similar chemicals produced from combustion of chlorine compounds
- Incineration of medical and municipal wastes
- Are incorporated in food web, humans ingest dioxins from contaminated meat, dairy, and fish
- Bioaccumulated in body fat
- Cause several kinds of cancer in lab animals
- Likely affect human reproductive, immune, and nervous systems. Passed in human milk to infants
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Hazardous Waste
- Types of Hazardous Waste
- PCBs-polychlorinated biphenils
- Group of 209 industrial chemicals
- Prior to 1970 ban by EPA, were dumped into landfills, sewers, fields-this why still dangerous today
- Serious health problems, liver/kidney damage, eyes, skin, reproduction
- Endocrine disrupters of thyroid gland, may be carcinogenic
- Several bacteria that degrade PCBs
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Hazardous Waste
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Hazardous Waste
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EnviroDiscovery
- Handling Nanotechnology Safely
- Nanomaterials: unique materials and devices at the ultrasmall scale of atoms and molecules
- Potential uses in medical treatment for cancer, solar panels to make electricity, heat resistant glass.
- Might pose health and safety risks
- EPA has adopted precautionary approach
- Burden of safety proof will be on companies that sell nanotechnology
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Global Climate Change
What is hazardous waste?
What are two sources of dioxins? Of PCBs?
Managing Hazardous Waste
- Learning Objectives:
Compare the Resource Conservation and Recovery Act and the Comprehensive Environmental Response, Compensation, and Liability Act (the Superfund Act).
Explain how green chemistry is related to source reduction
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Managing Hazardous Waste
- Chemical Accidents
- NRC – National Response Center
- On scene coordinator to determine size and chemical nature of incident
- Chemical Safety Programs have traditionally stressed accident mitigation and adding safety systems to existing procedures
- More recently, focus on accident prevention
- Principle of inherent safety: industrial processes are redesigned so that dangerous accidents are less likely to occur
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Managing Hazardous Waste
- Public Policy and Toxic Waste Cleanup
- Resource Conservation and Recovery Act
- Instructs EPA to identify which wastes are hazardous, and to provide guidelines and standards for hazardous waste programs
- Superfund Act - CERCLA
- Comprehensive Environmental Response, Compensation, and Liability Act
- Provides for the cleanup of abandoned and inactive hazardous waste sites
- At many of these sites, hazardous wastes have migrated deep into the soil and have polluted groundwater
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Managing Hazardous Waste
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Managing Hazardous Waste
- Managing toxic Waste Production
- Superfund Act deals only with waste produced in the past, not currently
- Most effective approach is source reduction
- Green Chemistry: commercially important chemical processes are redesigned to significantly reduce environmental harm
- Using less hazardous or non-hazardous materials
- Second best approach is to reduce toxicity
- By chemical, biological, or physical means
- Incineration is an example, but ash is hazardous
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Managing Hazardous Waste
- Hazardous Waste Landfills
- Waste that is not completely detoxified must be placed in long-term storage
- Toxic Waste Landfills
- Subject to strict environmental criteria and design features
- Layers of compacted clay and plastic liners
- Leachate is collected and detoxified
- Deep-well Injection
- For toxic liquid waste, such as explosives and pesticides
- Waste is injected deep underground between two impermeable layers
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Managing Hazardous Waste
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Case Study
- High-Tech Waste
- Average computer is replaced every 18–24 months
- Not broken, just rapid technological change
- Old computers work, but have no resale value
- Thrown away
- 80% of electronic devices go to landfills
- Huge waste of high quality plastics and metals, including toxic compounds
- 3-8lbs of lead per computer. Also cadmium, mercury, copper, tin palladium, etc.
- 20% of electronic devices are e-cycled
- Many are shipped overseas for recycling and recovery of useful materials, often in hazardous working conditions
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Case Study
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Global Climate Change
How are the Resource Conservation and Recovery Act and the Comprehensive Environmental Response, Compensation and Liability Act alike and what is the focus of each act?
How is green chemistry applied to reducing sources of hazardous waste?
