The Carbon Cycle - Q&A with Doug Wilson

Monday, June 10, 2019

Q. What does Eco Guardians do?

A. We divert food waste from landfill and convert it to fertiliser by a dehydration process.

Q. Does food waste in landfill cause CO2?

A. Actually, it creates methane which is 27 times WORSE than CO2 in its global warming effect. When we talk about landfill emissions, we use the term CO2e (carbon dioxide equivalent).

Q. How much greenhouse gas does food waste produce in landfill?

A. Every tonne of food waste in landfill rots and creates 1.9 tonnes of CO2e. There are also minor CO2 emissions from the fuel used to transport the waste to the landfill site.

Q. So any method of keeping food waste out of landfill will reduce GHG emissions?

A. That depends on the subsequent treatment of the waste. Some treatments themselves cause GHG and other pollutants and thus do not offer a complete solution. In the case of Eco Guardians, the main by-product is an organic fertiliser which definitely does complete the cycle in what is increasingly called The Circular Ecology.

Q. Is carbon dioxide a bad thing?

A. In moderation, no. In fact, it is essential. Carbon in soil is converted by natural cycles into CO2 which is an essential plant intake. Plants in turn emit oxygen which is essential for human existence. As plants and animals die, they contribute carbon back to the soil and so the cycle goes on.

Q. Why does everybody condemn CO2 then?

A. Because mankind has created far too much of it! We mine coal and drill for oil, removing these deeply sequestered forms of carbon from the soil. Then we burn those fuels, creating far more CO2 than the Earth’s vegetation can absorb. Thus, it remains in the atmosphere as a serious contributor to the greenhouse gas effect which in turn is a major cause of global warming.

Q. Why is organic fertiliser important?

A. Because it contains carbon in a form which is readily available to repair soils. Human actions have depleted soil carbon by the prolific use of chemical fertilisers and products such as chicken manure. These cause plant growth but leave no legacy of benefit to soil condition. Organic fertilisers, on the other hand, are beneficial both to plants and soil. It is increasingly understood that adding carbon to soil is one of the most important priorities we face. Assuming the world succeeds in reducing CO2 pollution, we must start now to sequester carbon in soil so that in the long run it can re-establish the natural carbon cycle.

Q. How good is Eco Guardians’ organic fertiliser?

A. It is so good that we call it SoilFood! Typically, every tonne of food waste that we treat creates 100 kg of SoilFood and, of that 100 kg, roughly 50% is organic carbon. 100 kg of organic carbon sequestered in soil contributes to soil repair while it is acted upon in the longer term by soil microbes and water to produce CO2 in a gradual process. That CO2 is taken up by plants which then emit oxygen for our benefit. Reversion to these natural cycles is increasingly vital while we collectively (hopefully) reduce the accelerated emissions of CO2 from industrial processes. In addition, SoilFood contains Nitrogen, Phosphate, Potassium and many other plant nutrients.

Q. Is there a downside to the EGPL SoilFood cycle?

A. A small one. To create the fertiliser and render it free of pathogens we use energy – electricity or gas, usually. The production of that energy in today’s world causes CO2 emissions, so Eco Guardians has to be fair and acknowledge this. Gas production does not cause big emissions – roughly 0.15 tonnes CO2e per tonne of waste treated. Electricity generation causes quite large emissions in Victoria because of the brown coal effect, while in Tasmania the emissions are very low because of hydroelectric generation. We can say on average that per tonne of food waste treated, the energy used is responsible for roughly 0.28 tonnes of CO2e.

Q. So what is the net effect of the SoilFood process?

A. Per tonne of food waste diverted from landfill:

- we avoid 1.9 tonnes CO2e landfill emissions

- we cause 0.28 tonnes CO2e on average in energy emissions

= a net reduction of 1.62 tonnes CO2e for every tonne of food waste diverted.

And then we add 100 kg of organic carbon to soil where it will be gradually converted to 0.36 tonnes of natural (rather than industrial) CO2 for plant benefit.

Q. Is there any other upside to the SoilFood process?

A. Yes, we are not finished yet! Food waste is typically 75 – 80% water. In landfill, that moisture contributes to the rotting process that causes CO2e and then eventually becomes leachate which pollutes water tables and waterways where it is a major cause of algal bloom. In the SoilFood process, on the other hand, after we have evaporated that moisture from the food waste, we condense it back to clear water that:

- can be harvested for use in cleaning or irrigation

- can be drained to sewer or to treatment lagoons as a beneficial dilutant for the pollutants entering from other sources. Water Authorities accept this discharge and do not impose any penalty charges for doing so.

To learn more about the SoilFood™ fertiliser or system, contact us here.

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Other food waste management services Eco Guardians Australia provides include

Compost making equipment

Kitchen grease trap machines

Kitchen exhaust canopy air filters

Food waste recycling in Sydney

Kitchen liquid trade waste management

Food waste recycling systems

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Monday, June 10, 2019