Analysis of data from household waste recycling centres has shown that fortnightly kerbside refuse collections boost recycling at HWRCs, writes Eric Bridgwater.
The ongoing furore about fortnightly collections shows no sign of abating, with secretary of state for communities and local government Eric Pickles indicating that a re-elected Conservative Government might use legal force to compel English councils to collect kerbside refuse weekly.
One of the issues touched on in the debate is whether fortnightly refuse collections result in householders taking more rubbish to their local household waste recycling centre (HWRC).There is a reasonable amount of anecdotal evidence that this takes place. For example, Veolia has recently noted that higher amounts of black bag waste are deposited at the sites it operates in Merseyside, where fortnightly refuse collections are provided.
As a waste data specialist, Resource Futures was interested in investigating whether any statistical evidence could be found for this effect. We analysed HWRC data for local authorities in the UK using WasteDataFlow tonnages from 2012/13.
We divided local authorities into two groups, depending on whether the main method of kerbside refuse collection in their areas was weekly or fortnightly. We excluded 10% of councils that had too much of a mix of kerbside refuse policies in their areas. But the remaining 90% provided an excellent sample for analysis.
And it was found that HWRC residual waste arisings are higher in areas with fortnightly refuse collection services. Surprisingly, though, there is a noticeable difference in HWRC recycling levels, with arisings much higher where rubbish is collected fortnightly.
This was such a significant and unexpected effect that we carried out further statistical analysis. We built a ‘multiple regression model’ in order to attempt to account for a range of factors likely to affect HWRC recycling levels.
The model showed that the effect of kerbside collection frequency is genuine, although not as pronounced as the chart suggests, because other factors are involved in affecting HWRC recycling performance. Nonetheless, there is convincing evidence that areas with fortnightly refuse collections are associated with higher levels of HWRC recycling, with fortnightly collections being associated with about 20kg per household per year (hh/yr) additional recycling.
This is fairly similar to the impact of fortnightly collections on kerbside recycling arisings, according to the best available statistical evidence. The average effect is around 25 kg/hh/yr additional kerbside dry and organic recycling (derived from Analysis of Kerbside dry Recycling Performance 2008/09, WRAP 2010, and Evaluation of the WRAP Separate Food Waste Collection Trials, WRAP 2009).
So while it seems that black bag waste is a genuine issue in areas with fortnightly collections*, this is more than outweighed by extra recycling at HWRCs in these areas. This could be due to residents who take their ‘excess’ kerbside rubbish to the HWRC also taking more recycling. Or perhaps it is due to higher levels of awareness in areas where the public are encouraged to improve their recycling behaviour by having their rubbish collection fortnightly. A similar effect was found by the National Assessment of Civic Amenity Sites project, which found higher HWRC recycling rates in areas with higher levels of kerbside recycling.
Whatever the reason, the best available evidence shows that there is a genuine link between fortnightly refuse collections and higher HWRC recycling arisings. This finding is highly relevant to the debate around rubbish collection frequency because it shows that if local authorities in England currently providing fortnightly refuse services were forced to change to a weekly service, they would be likely to experience a double whammy: a reduction in recycling at the kerbside and at HWRCs.
Eric Bridgwater is a principal consultant at Resource Futures