The plants?

Organic waste is containing carbon as fibers, proteins, carbohydrates which after conversion are providing carbon dioxide which is released in the environment. Some plants can pick up carbon dioxide again ...

..indeed plants are responsible (and by far more than human beings)

Dr Johan De Meester thank you for your contribution to the discussion

The more organic waste present in a landfill, the more landfill gas is produced by the bacteria during decomposition. Landfill gas (LFG) is a natural byproduct of the decomposition of organic material in landfills. LFG is composed of roughly 50 percent methane, 50 percent carbon dioxide (CO2) and a small amount of non-methane organic compounds. Each tonne of organic waste disposed of as landfill and broken down by anaerobic fermentation releases about one tonne of carbon dioxide equivalents (CO2-e) of greenhouse gases, mostly in the form of methane. The chemical aspects of plant decomposition always involve the release of carbon dioxide. In fact, decomposition contributes over 90 percent of carbon dioxide released each year. But wasted food isn't just a social or humanitarian concern it's an environmental one. When we waste food, we also waste all the energy and water it takes to grow, harvest, transport, and package it. And if food goes to the landfill and rots, it produces methane—a greenhouse gas even more potent than carbon dioxide. Plants remove carbon dioxide from the air naturally, and trees are especially good at storing CO2 removed from the atmosphere by photosynthesis.

When organic waste breaks down in a landfill it produces leachate and greenhouse gases such as methane and carbon dioxide. At kate Valley Landfill, this methane is collected through a network of pipes and used to create electricity.

When organic waste breaks down in a landfill it makes leachate and greenhouse gases such as methane and carbon dioxide. At Kate Valley Landfill, this methane is used to create electricity.

Organic waste and landfills

What is organic waste?

Organic waste is anything that was once living or made from something that was living eg food, garden and lawn clippings, animals and animal waste, paper, cardboard and timber.

Organic waste and landfills - like a big biodigester!

A biodigester is like a mechanical stomach. It is fed with organic material, which is broken down (decomposed) by micro-organisms (bacteria) in an oxygen-free (anaerobic) environment. The same thing happens when organic waste is put into a landfill. This process produces a liquid called leachate, and renewable energy called biogas (methane and carbon dioxide). Both of these are greenhouse gases.

Heather’s Small Scale Biodigester – YouTube video showing how a small home biodigester works.

Landfills for the future – Blog with information and comments on modern landfills as energy producing facilities.

A Modern Landfill – enlargement of the diagram in the above blog. Shows a similar system to Kate Valley Landfill.

The carbon cycle

Carbon from the atmosphere gets locked up by plants (in photosynthesis) and released back into the atmosphere either quickly (by respiration) or slowly by decomposition (eg breakdown of organic materials) or burning of fossil fuels. Methane is one of the carriers of carbon from organic material to the atmosphere so it’s part of the natural carbon cycle.

Carbon naturally moves from one part of the Earth to another through the carbon cycle. However, human activity is adding carbon to the atmosphere (in the form of carbon dioxide and methane) faster than natural processes can remove it. That is why the amount of carbon dioxide and methane in the atmosphere is increasing, which is causing the earth to warm and the climate to change.

This diagram of the carbon cycle shows how carbon is cycled between the air, oceans, ground and living things:

Greenhouses gases and the greenhouse effect

Greenhouse gases are found naturally in the atmosphere and keep our Earth warm enough to support life. They include water vapour, CO2, methane, and some others.

The Earth gets energy from the Sun in the form of sunlight. The Earth's surface absorbs some of this energy and heats up. That is why the surface of a road can feel hot even after the sun has set, because it has absorbed heat from the sun.

The Earth cools down by giving off a different form of energy called infrared radiation. However, before all this radiation can escape to outer space, greenhouse gases in the atmosphere absorb some of it, which makes the atmosphere warmer. As the atmosphere becomes warmer, it also makes the Earth's surface warmer, a bit like a greenhouse.

Planets without greenhouse gases get very hot when the sun shines on them but extremely cold at night time.

The Earth needs greenhouse gases to trap heat but if these gases increase too much the atmosphere will continue to get warmer, resulting in ‘global warming’. Carbon dioxide is the greenhouse gas you hear people talking about the most. That is because we produce more carbon dioxide than any other greenhouse gas and it is responsible for most of the warming. Greenhouse gases come from all sorts of everyday activities, such as heating our homes and driving around town.

The graph below shows the major greenhouse gases that are produced from human activity:

Methane

Besides CO2, another important greenhouse gas is methane (CH4). Methane is produced by bacteria that breaks down organic matter. You would expect landfills to create lots of methane - and they do!

Methane is an interesting (but bad) gas:

It is over 25 times more harmful as a greenhouse gas than carbon dioxide.

It can kill you if you breathe it (because it stops you absorbing oxygen).

It is very explosive.

Methane is, however, a valuable resource. Methane contains lots of energy:

Energy from the sun is absorbed by plants to make food.

Some of this food is eaten by animals.

Plants and animals and products made from them (eg paper, cardboard, timber, woollen carpets) all becomes organic waste.

When organic waste is broken down in a landfill they make leachate, CO2 and methane.

At Kate Valley the methane is collected through a network of wells and pipes then used to create electricity.

The pipes take the gas to large generators that produce 4 Megawatts of electricity each year. That electricity is fed into the national grid.

Some large homes use 10 Kilowatts (10,000 watts) of electricity each year.

So, 1 Megawatt (1,000,000 watts) of electricity would keep 100 houses in electricity for a year.

How many large houses could run on the Kate Valley 4 Megawatt generation plant?

Closing the loop

Kate Valley landfill controls the gas that comes from the breakdown of organic waste. This is called a ’Gas Management System’. Not only does it stop harm to the atmosphere, it also generates electricity from waste, a renewable resource.

The electricity created by organic waste at the landfill is being used to fuel new electric vehicles that collect waste - how cool is that!

Kate Valley will produce gas for several decades from now.

For more on electric vehicles, watch these Waste Management videos called Our First Electric Waste Truck hits the Road and Powering into the Future.

Organic waste and landfills

What is organic waste?

Organic waste is anything that was once living, such as:

food

garden and lawn clippings

animals and animal waste

paper

cardboard

timber.

Organic waste and landfills - like a big biodigester!

A biodigester is like a mechanical stomach that is fed with organic waste. The waste is broken down (decomposed) by micro-organisms (bacteria) in an oxygen-free environment. The same thing happens when organic waste is put into a landfill.

This process creates a liquid called leachate, and biogas (methane and carbon dioxide). Both of these are greenhouse gases.

Heather’s Small Scale Biodigester – YouTube video showing how a small home biodigester works.

Landfills for the future – Blog with information and comments on modern landfills as energy producing facilities.

A Modern Landfill – enlargement of the diagram in the above blog. Shows a similar system to Kate Valley Landfill.

The carbon cycle

Carbon from the atmosphere gets locked up by plants and released back into the atmosphere either quickly or slowly. Methane is one of the carriers of carbon from organic material to the atmosphere so it’s part of the natural carbon cycle.

Carbon naturally moves from one part of the Earth to another through the carbon cycle. However, human activity is adding carbon to the air (in the form of carbon dioxide and methane) faster than it can be removed. This is causing the earth to warm and the climate to change.

This diagram of the carbon cycle shows how carbon moves between the air, oceans, ground and living things:

Greenhouses gases and the greenhouse effect

Greenhouse gases are found naturally in the air and keep our Earth warm enough to support life. They include water vapour, CO2, methane and some others.

The Earth gets energy from the Sun in the form of sunlight and heats up. When the Earth cools down it gives off a different form of energy called infrared radiation. Greenhouse gases in the air hold on to some of this radiation, which makes the air warmer - a bit like a greenhouse.

Planets without greenhouse gases get very hot when the sun shines on them but very cold at night time.

The Earth needs some greenhouse gases to trap heat but if these gases increase too much the air will keep getting warmer.

There are different types of greenhouse gases. Carbon dioxide is the greenhouse gas you hear people talk about the most. That is because we produce more carbon dioxide than any other greenhouse gas and it causes most of the warming.

Greenhouse gases come from all sorts of everyday activities, such as:

heating our homes

driving cars and trucks.

The graph below shows the main greenhouse gases:

Methane

Another important greenhouse gas is methane (CH4). Methane is made when organic matter rots. You might think landfills make a lot of methane - and they do!

Methane is an interesting (but bad) gas:

It is more harmful than carbon dioxide as a greenhouse gas.

It can kill you if you breathe it.

It is very explosive.

Methane is also valuable because it has lots of energy. At Kate Valley the methane is collected through a network of pipes. The pipes take this gas to large generators that make electricity.

Closing the loop

Kate Valley Landfill controls the gas that comes from organic waste. Not only does it stop harm to the air, it also makes electricity from the gas.

The electricity created by organic waste at the landfill is being used to fuel new electric vehicles that collect waste - how cool is that!

For more on electric vehicles, watch these Waste Management videos called Our First Electric Waste Truck hits the Road and Powering into the Future.

Dr Godwin Sabah thank you for your contribution to the discussion

Plants remove carbon dioxide from the air naturally, and trees are especially good at storing CO2 removed from the atmosphere by photosynthesis. Photosynthesis removes carbon dioxide from the atmosphere and fixes it in producers as organic compounds. Respiration releases carbon dioxide into the atmosphere when organic compounds are digested in living organisms. Plants take up carbon dioxide through the process of photosynthesis, locking it away in their tissues, making the world's forests, grasslands, soils and wetlands huge reservoirs of carbon. Nutrients like iron can be added to the ocean to spur phytoplankton growth, a process called ocean fertilization. Phytoplankton take up carbon dioxide, convert it to biomass, and then some will sink to the deep ocean, sequestering that carbon. This strategy relies on the ocean's “biological carbon pump.More than 2 billion tonnes of carbon dioxide is being removed from Earth's atmosphere each year, according to an analysis of global efforts to capture and store the greenhouse gas. Allowing forests to regrow, restoring coastal wetlands, and switching to restorative agricultural practices, such as cover crop rotation, that support healthy soils. These ecosystems reduce climate change by capturing CO2 from the air and sequestering it in plants, soils, and sediments.Carbon sinks” to refer to places where carbon is stored away from the atmosphere. Plants constantly exchange carbon with the atmosphere. Plants absorb carbon dioxide during photosynthesis and much of this carbon dioxide is then stored in roots, permafrost, grasslands, and forests. When organic waste is put into a landfill, it breaks down by a process called anaerobic decomposition. The organic waste creates a liquid called leachate, and two main gases - methane (CH4) and carbon dioxide (CO2), both of which are greenhouse gases.Landfill gas (LFG) is a natural byproduct of the decomposition of organic material in landfills. LFG is composed of roughly 50 percent methane, 50 percent carbon dioxide (CO2) and a small amount of non-methane organic compounds. When organic waste decomposes, carbon dioxide and methane gas is created. Methane is created when there is no air present, while carbon dioxide is the natural product when anything rots in air.