The reason food waste is collected is so that it can be used to benefit the environment. Kitchen caddy liners are shown to increase uptake of this service, but most councils recommend bioplastics or provide cornstarch liners free of charge.
These cannot be processed in an anaerobic digestion (AD) facility, so they have to be removed from the composting process. At best they provide no benefit to the environment and at worst they are sent to landfill.
If 50,000 households use three liners a week they will require 7.8 million liners a year, which is a lot of waste material to provide for free. Each liner weighs about 6g so all those cornstarch liners equate to around 44 tonnes of unnecessary waste each year.
What would the householder say if it was publicised that the liners they are provided with, or dutifully buy, cannot be composted in AD, provide no benefit to the environment and are often landfilled?
On top of this, less than a third of the liner is actually biodegradable. The typical composition of a cornstarch liner is about 67% polyester, 26% starch, 4% ash and 3% water. This is even before the ethical arguments start about using a food crop to create bin liners.
Huge sums of money are being spent on researching how to produce bioplastics that can be processed using AD, but there has been little success to date.
The question today is why councils continue to recommend bioplastics or spend money on research when the answer is already widely available: in fact it is extensively used across Scandinavia as well as by many forward-thinking UK councils.
Paper liners solve all the problems associated with bioplastics and will ultimately benefit the environment.
They do not have to be separated from the food waste. New research by the University of Glamorgan shows that each 10-litre paper liner will produce 0.3p-worth of electricity when processed in AD. So 7.8 million paper liners will produce more than £23,000-worth of electricity each year.
When correctly certified these liners fully meet EN13432, and are 100% biodegradable and 100% compostable. The paper used is FSC-certified to show that it is harvested from carefully managed forests where four trees must be planted for every tree harvested. Kraft paper is manufactured from the pulp and tree waste from the timber industry.
Councils will argue that paper liners are more expensive than cornstarch. But bioplastics are considerably more expensive than plastic and yet householders are willing to pay the extra because their local authorities have given sound reasons as to why they are better. Furthermore they will not accept non-biodegradable liners.
I believe that when given detailed and sound reasons, the environmentally aware householder who participates in food waste collections will be prepared to stretch to the average 2p per liner extra for paper.
Councils say that AD operators tell them they have no difficulty with cornstarch because it can be depackaged. But AD operators say they have to find a way around the problem because councils insist on using these liners.
The operators also feel that a refusal to accept food waste in cornstarch would put them at a competitive disadvantage when tendering because councils are more likely to award a contract to a bidder that is happy to depackage cornstarch.
Perhaps now is the ideal time, while AD is still in its infancy in the UK, for councils, waste managers and AD plant operators to take that final environmental step and insist that, if a householder wants to use a caddy liner, it must be paper.
Chris Molloy, managing director, Svenco UK