Waste Disposal:
Waste Classification:
hazardous/toxic
industrial
municipal
biological
farm wastes
animal processing
mineral processing
All of these wastes have varying degrees of environmental impact and each must be disposed of safely.
Landfills:
Traditionally wastes were disposed of in open dumps, pits, sinkholes or even in wetlands.
Problem with odors, pests, runoff to surface and ground water.
Sanitary Landfill: waste is covered with soil layer every day. Improvement: reduces odors and pests.
Problem with water leaching through the landfill into the groundwater below.
With changing environmental attitudes landfill design has steadily improved. A Modern landfill may incorporate any or all of the features below to ensure environmental integrity.
Geologic Setting: more consideration of location, placing landfill on impermeable strata to keep leachate from the groundwater.
Geomembrane: a liner that acts as a barrier to leachate.
Leachate Collection: structures to collect and treat leachate that collects at bottom of landfill.
Methane Collection: structures to collect methane that is produced in the landfill. This may or may not be used for energy production.
Secure Landfill: the highest level of safety, used for the disposal of hazardous or toxic wastes. The landfill usually has a concrete bottom and sides, leak detectors and leachate treatment facility.
Space for landfills is running out. Thoughts on handling waste include recycling, reduction of waste and alternatives to waste disposal.
Alternative Methods of Waste Disposal:
Land Farming: spread waste onto land and allow natural processes and biological activity to degrade wastes. Petroleum products have been disposed of in this manner for the last 40 years.
Pros: reasonable inexpensive, environmentally safe, improves soil structure
Cons: leaking to groundwater, takes lots of space, can only be used to degrade organic material.
Incineration: burns wastes at high temperatures. Reduces waste volume by 75-95%. Gases, liquids and solids can be disposed of in this method but must be combustible.
Pros: reduces waste, good method for disposing of hazardous or toxic material. In some instances has been used to generate energy.
Cons: expensive because air pollution controls must be in place. Mobile units can be used for hazardous waste sites.
Ocean Disposal: used for many substances including dredge spoil, sewage sludge, municipal garbage.
1972 Ocean Dumping Act listed wastes that could be disposed of through ocean dumping.
Prohibited: mercury compounds, high-level radioactive wastes, inert material that will stay suspended, petroleum products
Allowed: low level radioactive waste, sewage sludge, dredge spoils
Deep Well Injection: disposal of liquid hazardous wastes into permeable strata.
Pros: inexpensive, simple.
Cons: concern with leakage into groundwater, reactions with solvents, earthquakes.
Radioactive Wastes: low level and high level wastes. Sources come from laundering, processing of wastes, lab wastes, hospital wastes, spent fuel, power plant cooling water. Low level wastes disposed of in secure landfills. High level wastes currently stored at high level waste facilities. Yucca Mountain high level waste facility.
