Hazardous Waste and Sanitary Landfills

1. Hazardous Waste and Sanitary Landfills 9/2/11

2. What is an open dump landfill? • Open dump landfills are uncovered piles of solid waste. • They are more common in undeveloped countries.

3. What are Sanitary Landfills? • Solid wastes are spread into thin layers, compacted and covered daily with fresh clay or plastic foam to prevent leachate.

4. What are the Pros and Cons of Sanitary Landfill? pros cons • Low operating Costs • Can Handle Large amounts of waste. • Filled Land can be used for other purposes. • There limited landfill space in many areas. • Noise, traffic, dust • Greenhouse gases • Output approach that encourages waste reduction • Leachate – groundwater contamination

5. What is incineration? • Burning trash

6. What are the pros and cons of Incineration? pros cons • Reduces trash volume • Produces energy • Concentrates hazardous substances for burial • Sale of E reduces cost • Expensive • Produces hazardous waste • Emits air pollutants • Encourages waste production

7. What is hazardous waste? • Any substance that is: • Flammable • Reactive • Toxic • Corrosive

8. How can we detoxify hazardous waste? • Physical methods • Chemical methods • Nanomagnets • Biological – bioremediation and phytoremediation • Plasma Arch torch

9. What are the physical methods for detoxifying hazardous waste? • Charcoal resins to filter solids • Distilling liquid wastes to separate out harmful chemicals

10. What are chemical methods to detoxify hazardous waste? • Chemical reactions (i.e. neutralization) to convert hazardous chemicals to less harmful chemicals.

11. What are nanomagnets? • Magnetic particles coated with compounds to remove various pollutants from water.

12. What is bioremediation? • Use of biological agents, such as bacteria or enzymes to destroy toxins or convert them to less hazardous waste.

13. What is Phytoremediation? • The use of naturally or genetically engineered plants to absorb, filter or remove contaminates from soil and water.

14. What does a plasma arch torch do? • Breaks down hazardous waste at very high temperatures.

15. How can we store hazardous waste? • Deep well disposal • Surface impoundments • Above ground storage facilities

16. What is deep well disposal? • Hazardous wastes are pumped through a pipe full of dry, porous rock, where they soak into the rocks.

17. What are the pros and cons of deep well disposal of Haz. Waste? pros cons • Safe at certain sites • Wastes can often be retrieved • Low cost • Leaks from corrosion of well casing • Emits air pollutants • Encourages waste production

18. What are surface impoundments? • Lined ponds, pits or lagoons in which liquid hazardous wastes are stored.

19. What are the pros and cons of surface impoundments? pros cons • Low Costs • Waste can often be retrieved • Can store wastes indefinitely with secure double liners • Groundwater contamination from leakage liners and overflow • Air pollution from volatile organic compounds • Encourages waste production

20. FRQ check • Annual precipitation at a landfill in the town of fremont is 100 mm per year, and 50 percent of this water runs off the landfill without infiltrating the surface. The landfill has a surface of 5,000 m2. Underneath the landfill, the town installed a leachate collection system that is 80 percent effective. Any leachate not collected by the system enters the surrounding soil and ground water. This leachate contains cadmium and other toxic materials. • Calculate the volume of water in cubic meters (m3) that infiltrates the landfill per year.

21. 100 mm/year = 0.1 m/year • 0.1 m/year x 5,000 m2 x 50% = 250 m3 • So the volume of leachate in a m3 that is treated per year is 250 m3 x 80% = 200 m 3