Question

Sanitary landfill and incineration are two methods of waste disposal. Briefly describe the two processes. Suggest any other ecofriendly method of waste disposal of biodegradable wastes.

Answer 1

1. Sanitary landfill: A sanitary landfill is a method of disposing of waste. Trash can be disposed of on land in a sanitary landfill without producing nuisances or jeopardising public health and safety. The rubbish is disposed of in areas that have already deteriorated or need to be restored in the most environmentally friendly way possible. One advantage of employing a sanitary landfill is that it separates solid trash from the surrounding soil and water. The disadvantages of a sanitary landfill include the negative impacts of leachate and methane gas leaks, as well as ecosystem destruction on the landfill site.
   
   To ensure safe disposal, the waste in a sanitary landfill follows the steps below:
   1. The sanitary landfill starts with a liner that works as a barrier, keeping leachate from damaging soil and groundwater near the landfill site.
   2. Aerobic bacteria consume the available oxygen in the early stages of their activity, raising the temperature. The second step establishes anaerobic conditions, resulting in the formation of carbon dioxide and hydrogen.
   3. Phase three sees the development of the bacterial population and the onset of methanogenic activity, which is the process by which organic matter degrades to produce methane.
   4. After the organic material is depleted in the fifth phase, the system resumes its aerobic state.
   5. Over time, the waste decomposes beneath the soil. Decomposition byproducts, such as leachate and methane gases, are environmentally hazardous. Methane collection systems reduce greenhouse gas emissions. Leachate collection systems help keep groundwater and soil clean.
2. Incineration: Incineration is the process of burning or combusting domestic waste, often known as non-hazardous Municipal Solid Waste (MSW). Waste-to-energy plants burn waste in incinerators. The garbage is disposed of and the heat produced by burning it is used to generate energy. The incineration process begins with the material being delivered to the waste-to-energy facility and stored in a trash storage bunker, also known as the pit. The garbage is separated and shredded. A powerful magnet sweeps through the garbage, removing valuable metals that may be recycled. The waste is then pushed into the primary chamber, also known as the combustion chamber and burned at temperatures around 1500 degrees Fahrenheit. The garbage is transformed into ash. Water is pumped through the exterior of the combustion chamber, where it is converted to steam due to the intense heat generated. The steam is then sent to a generator system to spin a turbine, producing energy. Incinerators are recognised as waste-to-energy plants due to their ability to generate power.