Landfill is the cheapest way of disposing MSW, but all efforts to get rid of waste pollute the environment to some extent. In landfills the disadvantages are that gases and chemicals are released into the air we breathe. Experiments show that the gases and chemicals released from landfill sites are harmful to animals which common sense would tell us, it’s harmful for us too.
Early landfills were put in convenient locations on the least expensive land. The waste was ‘out of sight out of mind.’ People did not realize that as the waste rots and decomposes, it can release toxic chemicals.
However, there is another problem with landfills, whether lined or not. Bacteria in the soil, break down organic matter in the landfill, such as vegetable peelings. As they do so, they release methane gas. Methane is not a poison, but it has two drawbacks. Firstly, it is a greenhouse gas. It contributes to the greenhouse effect that is causing global warming. Secondly it is explosive. If it seeps from the landfill and finds its way into a building, it can build up unnoticed.
Methane Collection System
Bacteria in the landfill break down the trash in the absence of oxygen (anaerobic) because the landfill is airtight. A byproduct of this anaerobic breakdown is landfill gas, which contains approximately 50 percent methane and 50 percent carbon dioxide with small amounts of nitrogen and oxygen. This presents a hazard because the methane can explode and/or burn. So, the landfill gas must be removed. To do this, a series of pipes are embedded within the landfill to collect the gas.
More recently, it has been recognized that this landfill gas represents a usable energy source. The methane can be extracted from the gas and used as fuel. The extraction system is a split system, meaning that methane gas can go to the boilers and/or the methane flares that burn the gas. The reason for the split system is that the landfill will increase its gas production over time and exceed the capacity of the boilers at the chemical company. Therefore, the excess gas will have to be burned. It is not cost-effective to compress the excess gas to liquid and sell it.
The U.S. Environmental Protection Agency (EPA) has endorsed landfill gas as an environmentally friendly energy resource that reduces our reliance on fossil fuels, such as coal and oil. Landfill gas-to-energy projects are most successful when partnered with mature MSW landfills, as opposed to new landfills or C&D landfills.
There are three basic types of landfill gas-to-energy facilities:
Electric – Landfill gas is used as a fuel to generate electricity at small power plants at the landfill, or at a nearby industry, with the generated electricity delivered to a utility company.
Alternative fuel – Landfill gas is piped to an industrial or commercial facility, where it is used for heating in place of, or in combination with, fossil fuels such as oil, coal or natural gas.
Processed gas – Landfill gas is processed and cleaned to natural gas quality and delivered to transmission pipelines, to be used in normal applications for natural gas.
Landfill gas is still a problem. The Greenhouse Effect is caused by so called ‘greenhouse gases’ in the atmosphere. These gases, such as carbon dioxide, methane, and water vapor have existed naturally for millions of years. The amount of these gases has gradually increased, causing the earth to get warmer.
Landfill are a lot nastier than I had previously thought. I can’t believe that people think all this work is easier than just recycling. Recycling may be harder in the short run, but it seems like something that will save us a lot of problems and time in the long run.