Having bigger bins for residual waste can lower recycling rates, according to a report published by the Waste & Recycling Action Programme (WRAP).

‘Analysis of recycling performance and waste arisings in the UK 2012/13’, published yesterday (22 July), was produced to give local authorities (LAs) and waste management companies information on what elements impact on recycling performances in the UK, and the extent to which they do so.

Data from 239 LAs was analysed for the report - those that ‘provide the same collection service for paper, card, cans, glass and plastic bottle to 80 per cent or more of their households’. In total 60 per cent of all UK LAs with responsibility for collection services were included in the study.

WRAP’s analysis of the data found that an increase in effective weekly residual containment capacity from 120 to 240 litres is associated with decreases in recycling rates of around 7.2 percentage points.

This, the report reasons, is ‘due to decreases in dry recycling yields and increases in residual waste yields’. This particular impact was found to be great in England datasets than for those from the rest of the UK.

Food waste and green waste collections raise recycling rate

There was, however, found to be ‘no significant relationship’ between residual containment capacity and total waste arisings, which WRAP suggests indicates that in areas where capacity for residual household waste is lower, the waste is diverted to other streams, such as household waste recycling centres (HWRCs).

Lower recycling rates were also recorded in areas with subscription garden waste collection, or none at all; while LAs with separate food waste or mixed food and garden collections were associated with a higher recycling performance than those with none. The report found that inclusion of these collections raised the recycling rate by around 8.8 per cent.

The report measured no significant difference in average recycling rate between LAs with separate and mixed garden collections, ‘contrary to other evidence on food waste collections’, which indicates that separate collections achieve higher yields of food diversion.

Surprisingly, WRAP’s analysis of the data concludes that ‘very little certainty can be applied in establishing a difference in recycling performance between dry scheme types’.

The datasets for the study included LAs using co-mingled (fortnightly, weekly and fortnightly with glass at bring sites), multi-stream (weekly and fortnightly) and two-steam (fortnightly) systems, but the report claims that ‘there is very little difference in recycling rates whatever the dry recycling schemes in operation’.

Contextual variables

As well as the effect of different services on the recycling rate, the study recorded factors outside the control of LAs that have an influence.

These contextual variables explain between 16 and 29 per cent of the variation in the recycling rates, according to the study, compared to 39 to 65 per cent of LA-controlled variables.

Higher level of deprivation is associated with lower overall recycling rates, lower dry yields, and lower total arisings, but not with a difference in residual yields.

The situation of an LA also has an effect, with the report suggesting that increased rural nature beings a higher recycling rate, ‘as a result of higher dry, organic and total arisings yields’.

Predicting recycling rates

WRAP hopes that the conclusions made in this study will help LAs and waste management companies effectively plan their recycling schemes.

By giving each variable a measurement of significance and approximate value, the model ‘can be used to predict the recycling rate for any LA’.

For example, an authority with a fortnightly two-stream collection, effective weekly residual containment capacity of 180 litres, 45 per cent rural nature, 28 per cent working age population in social grades D and E, a subscription garden service, a separate food waste collection, and pots, tubs, and trays kerbside collections, is predicted to have a recycling rate of 40.8 per cent.

Interpreted data ‘hugely important’ for authorities

Linda Crichton, Head of Resource Management at WRAP, explains: “Recycling rates vary throughout the UK just as they do in other countries, and the reasons for this are complex.

“They can be within the control of an authority or contextual factors, such as demographics, that are beyond the authority’s control. Being able to quantify the degree to which each impact on recycling is hugely important for an authority, and this report will help make that possible.”

Read WRAP’s ‘Analysis of recycling performance and waste arisings in the UK 2012/13’ report.