Findings from a study carried out at Southampton University challenges the thinking behind Communities Secretary Eric Pickles’ efforts to encourage councils to revert back to weekly waste collections.

The results also contradict claims made just last week from a leading reprocessor that the economics for commingling stack up far better than kerbside sorting due to the high volumes that can be achieved.

The research, carried out by the University’s waste management research group, was based on extensive trials at Lichfield District Council, one of the top 20 performing waste collection authorities in England since 2000.

Since 2002-3, the South Staffordshire waste collection authority had operated weekly collections of commingled dry recyclates alongside fortnightly collections of food, garden and residual waste, but problems with the scheme led to the introduction of a new dry recyclates collection service, which was trialled in three villages in the district during 2009.

Two trials between March and June gave the researchers the opportunity to evaluate single and dual stream collection methods for alternate weekly collections and compare performance with the previous weekly system.

Researchers also examined changes to collection frequency, the type of container issued to households, the amount of sorting required of residents, household participation and productivity levels.

Households were surveyed before the change in collection frequency was brought in and the quality of the recyclate collected was examined in 2008-9 and 2009-10.

The trial findings revealed that reducing the frequency of collections did not have a negative impact on the yield of recyclates collected.

Both the dual and single stream trials saw an increase in the amount of recyclates collected per household during the trial period compared to the same period of time in the previous year.

Interestingly, the dual stream option was better for obtaining maximum yields of recyclates while the single stream proved significantly cheaper in terms of vehicle and staff costs, was far easier for the crew to manage operationally and was easier for residents to understand.

“Our literature review combined with the results from our study show the multiple benefits of the alternate weekly collection system,” said Professor for Applied Environmental Science Ian Williams, one of the two study authors.

“We often hear politicians talking about evidence-based policy and it would be interesting to see how ministers respond to this evidence.”

Despite some political opposition and a vociferous campaign by national media, most local authorities have chosen to adopt an alternate weekly collection of residual waste and recyclables, primarily to save on costs and increase the volume of waste recycled.

While the idea behind alternate weekly collections is to encourage households to recycle more, some commentators have challenged the degree to which this system maximises waste collections.

The findings from the study will be published shortly in the Science of the Total Environment journal.

Nick Warburton

Action inspires action. Stay ahead of the curve with sustainability and energy newsletters from edie