Instructor’s Manual for Environmental Science, 15th edition
B. Sanitary landfills are where solid wastes are spread out in thin layers, compacted, and covered
daily with a fresh layer of clay or plastic foam, which helps to keep the material dry and reduces
leakage of contaminated water.
C. Open dumps are essentially fields or holes in the ground where garbage is deposited and
sometimes burned.
2. China disposes of about 85% of its solid waste in rural open dumps or in poorly designed and
poorly regulated landfills.
D. Advantages of sanitary landfills:
1. Low operating costs
3. Filled land can be used for other purposes
4. No shortage of landfill space in many areas
E. Disadvantages:
1. Noise, traffic, and dust
3. Output approach that encourages waste production
16-5 How should we deal with hazardous waste?
A. We can use integrated management of hazardous waste.
1. Integrated management establishes three levels of priority:
2. Industries try to find substitutes for toxic or hazardous materials, reuse or recycle the hazardous
materials within industrial processes, or use them as raw materials for making other products.
4. Most e-waste recycling efforts create further hazards and can result in serious threats to other
species.
5. CONNECTIONS: Cell Phones and Endangered African Gorillas.
a. Most cell phones contain coltan, a mineral extracted in the deep forests of the Democratic
Republic of the Congo in central Africa, which is also the home of the endangered lowland
gorillas. Coltan mining has dramatically reduced the gorilla habitat and contributed to the
killing of gorillas to feed the miners.
b. Recycling old cell phones reduces the need to mine coltan and helps save the remaining
lowland gorillas.
B. CASE STUDY: Recycling E-Waste
1. In some countries, workers in e-waste recycling operations are often exposed to toxic chemicals as
3. Thirty-five states have banned the disposal of computers and TV sets in landfills and incinerators
and thirteen have laws that make manufacturers responsible for recycling most electronic devices.
5. Proponents call for a standardized U.S. federal law that makes manufacturers responsible for
taking back all electronic devices they produce and recycling them domestically.
C. We Can Detoxify Hazardous Wastes
1. Biological methods for treatment of hazardous waste may be the wave of the future.
3. Phytoremediation involves using natural or genetically engineered plants to absorb, filter, and
remove contaminants from polluted soil and water.
4. Hazardous wastes can be incinerated to break them down and convert them to harmless or less