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Co-mingled recycling has again proved that it can lift the performance of municipal collections, according to waste management specialist Greenstar UK.

Data from five local authorities that switched to collecting single-stream commingled dry recyclables showed an average 78 per cent improvement in recycling tonnages, with the biggest increase reaching nearly 190 per cent.

Ian Wakelin, Greenstar UK chief executive officer, said that the facts about what co-mingled collections can and do achieve ‘underline again that they must remain a key component in the municipal recycling toolbox’.

He said that the facts also rebut a Waste and Resources Action Programme (WRAP) statement in a recent media report about the agency’s analysis of collection systems that show no statistically significant difference in the weight of materials collected via kerbside-sort and co-mingled collections.

Wakelin added: ‘Greenstar collects recyclables from around 1.2 million homes, many of which have converted from a kerbside-sort to a single-stream system.

‘Any double-digit improvement in collected weight would be significant – and an improvement averaging 78 per cent is massively significant,’ he said.

According to Greenstar UK and other advocates of this form of recycling, co-mingled collections are easier for householders to understand and use, while collection crews find them safer and more efficient.

Thanks to advanced technology and automation at materials recycling facilities, co-mingled recyclables can be turned into marketable, quality recyclates.

While the reject rate for co-mingled recyclates can sometimes be a few percentage points higher than that for source-separated recyclables, Wakelin believes that this is an acceptable trade-off for the substantial volume increases achieved.

He said: ‘If our smart processing and quality control identifies recurring contamination, we can alert the supplying local authorities and help them tighten up their collections so as to drive up quality.’ Next year, the UK must lift its recycling performance by at least three per cent if it is going to hit its 2010 recycling target of 40 per cent and Wakelin claims that the target will keep climbing.

He asks: ‘There have been some remarkable gains in Britain’s recycling in the last few years, but just how are councils going to lift their performance in the few months that are left this year? ‘I suggest that they consider commingled collections where these are appropriate.

‘There is a clear role for kerbside-separated collections where they are suitable, but if any council is wondering how to make a near-immediate, significant and long-term leap with its recycling, the option of single-stream commingling has to be very high on its agenda,’ added Wakelin.

Data was collected from Walsall Council, Stratford-on-Avon District Council, Blackburn with Darwen Borough Council, South Oxfordshire District Council and the London Borough of Waltham Forest.

Greenstar’s municipal services subsidiary Verdant provides recycling and refuse collections for the latter four authorities.

The company designed and launched fortnightly commingled collections for Stratford and South Oxfordshire, as well as introducing Blackburn with Darwen’s single-stream commingled service and Waltham Forest’s commingling pilot.

Walsall Council sends dry recyclables to Greenstar’s ‘super MRF’ at Aldridge for processing.

Barring Waltham Forest, all these authorities collect mixed dry recyclables (card, paper, metal, plastic and glass containers) in single wheeled bins that are collected fortnightly from residents’ kerbsides right across their respective districts.

Waltham Forest has just concluded a three-month pilot service based on weekly collections of single-stream commingled dry recyclables from around 12,000 households using either sacks or wheeled bins.

Walsall Council introduced kerbside single-stream commingled collections using wheeled bins in February 2009.

In the three months up to and including January 2009, a total of 2,306 tonnes of recyclables were collected under the old system (a monthly average of 769 tonnes).

In the six months from February to July 2009, the new system – which extended the range of materials to include cardboard and plastic – collected a total of 13,344 tonnes of dry recyclables (a monthly average of 2,224 tonnes), which represents an improvement of 189 per cent.

Stratford-on-Avon District Council introduced fortnightly kerbside single-stream commingled collections of dry recyclables from its 53,000 households in August 2008.

In the year from April 2007 to March 2008, the old system collected 7,773 tonnes of dry recyclables.

Between August 2008 and March 2009, the new collection system collected an annualised total of 14,055 tonnes of recyclables – an improvement of almost 81 per cent.

The 59,000 households in Blackburn with Darwen Borough Council changed from weekly dual-stream commingled collections to fortnightly single-stream commingled collections.

The phased introduction, completed in October 2008, included moving back from fortnightly to weekly residual waste collections.

The old system collected 9,170 tonnes of recyclables in the year from September 2006 to August 2007, while from October 2008 to March 2009 the new single-stream system collected an annualised total of 12,443 tonnes of dry recyclables – a gain of nearly 36 per cent.

Verdant launched a fortnightly kerbside single-stream commingled collection system for South Oxfordshire District Council in early June 2009.

In 2008-09, some 12,061 tonnes of dry recyclables were collected from just more than 56,000 households in the district.

Based on data from the new scheme to date, collection tonnage has increased by more than 40 per cent.

When combined with food and green waste collections, the total recycling and composting rate is more than 70 per cent.

In partnership with the London Borough of Waltham Forest, Verdant ran a three-month pilot from April to June 2009 to evaluate the impact of single-stream commingled collections, compared to the borough’s usual weekly collection of source-separated recyclables.

Around 12,000 households used either a sack or a wheeled bin to collect commingled dry materials for weekly collection.

When compared to the corresponding period in 2008, the wheeled bins increased tonnage by an average of 42 per cent, while sacks made little impact on historic collection volumes.

A recent report by West Cheshire and Chester council about the mid-June launch of its new collection service said that it had doubled its recycling and composting rate to around 55 per cent.

The new service features a fortnightly collection of single-stream commingled dry recyclables from a wheeled bin, a fortnightly collection of garden waste from a wheeled bin and the weekly collection of residual waste from a smaller 140-litre wheeled bin.

According to Wakelin, it was significant that a recent policy statement by the Conservatives indicated tacit support for commingling as a useful – but not the only – recycling methodology.

Nick Herbert, shadow environment secretary, said that the Conservatives are sceptical of the idea that government should mandate kerbside sort as the sole method of collection by local authorities.

He added: ‘Clearly it is important that we seek to get the highest value possible from the recyclables that are collected, but advances in technology should mean that this can still be achieved with commingled collection.

‘Commingling also has the obvious benefit of not overburdening the public with an array of boxes and bins.

‘There is currently a role for both commingling and kerbside sort, but it should be for local councils to decide what works best for them,’ said Herbert.

The Policy Exchange think-tank stated that councils should be prevented from forcing an excessive number of bins on households as councils that require their residents to keep five bins risk overloading householders and generating resentment.

It added that three bins, for food waste, dry recyclates and residual waste, should be the limit on what householders can be expected to use.

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