"Recycling" Food Waste

There are moves afoot to begin uplifting food waste separately from other waste to allow energy to be extracted through the use of anaerobic digestion. On the face of it this sounds like a very good idea – not only does it extract energy but the residual waste can be used as a commercial grade compost, unlike the low grade compost extracted from Mechanical Biological Treatment (MBT) systems. This would see large reductions in material going to landfill.

My concern is that large scale adoption of this technology will encourage more waste or, at best, stop any further reduction in the food we waste.

Here is why.


The processing plant required for this operation must be designed to process a specific quantity of food waste for optimum operation. It will be capable of operation with a little less but there comes a point where it would not operate efficiently to the point where it recovers less energy than that used to collect the waste.
Treatment of our waste in this manner is normally performed by commercial waste management contractors who would not invest in expensive processing equipment without confidence that they will obtain sufficient return. To obtain the required return, the plant must operate efficiently for perhaps twenty or more years. For this reason, the contractors would require a contract with the local council to ensure that there will be sufficient raw materials, i.e. food waste. Depending on the nature of the contract, the council may be liable to compensate the waste management contractor if there is a reduction in waste quantity. Hence the incentive to not reduce food waste.

Given the food shortages in many parts of the world and the vast quantity of food that is wasted globally, it is more important to reduce food waste than to recycle it or, more correctly, recover energy from it.  I would also be surprised of the amount of energy recovered from the waste exceeds the energy used in producing it and collecting the waste.

As with all types of recycling, we should:
- reduce waste first, e.g. by meal planning and weighing out portions;
- reuse, e.g. use leftovers in another meal;
- and as a last resort dispose of the waste food.