Feed Me Now

TB1Tony Breton tells us why he thinks end product quality is being threatened by the anaerobic digestion industry’s ever increasing hunger for feedstocks.
Published in the CIWM Journal May 2013


The organics industry can learn a lot from the recent battle of quality vs quantity. Where you have collection systems, which give preference to higher volumes over higher quality, there is a resignation that a highly sophisticated and thus expensive contamination removal system will be needed. Add in a general lack of transparency regarding whole system efficacy and everyone’s happy… well everyone bar the final reprocessor who, despite the promises of purity, still receives highly contaminated feedstocks, and naturally those footing the bill. Of course, addressing the performance of the collection system is only part of the solution and indeed, even then some level of an engineering solution is going to be needed, but where does the balance lie?

Tony Breton – “The success of the government’s drive for more AD combined with the natural pressure from investors…is driving down gate fees, increasing contamination/non-target materials, and thus threatening end product quality…”

Sometime in the mid 1990s when the first garden waste contracts were being drawn up the topic of contamination came up and someone stuck their finger in the air and said five percent sounds good, and this has stuck ever since. In the murky world of MRFs, five percent contamination/non-target materials sounds like a dream feedstock but in one tonne of biowaste five percent plastics equates to >6500 plastic carrier bags. Then, due to the natural losses incurred through composting, if you do nothing to address plastics between receiving the biowaste and undertaking a PAS100 physical contaminant test, the initial five percent will become 18 percent by weight and the PAS100 pass level is 0.125 percent. This infamous five percent just doesn’t stack up in today’s market.

In 2010 a short Association for Organics Recycling survey of its members found on average they were receiving 4.06 percent contamination with an average cost per tonne of removing/disposing the contaminants to produce a marketable. The 2010 WRAP Organics Recycling Survey estimated that there was 5.4m tonnes of composting, taking an average of £17.50 per tonne to clean, and cost the industry ~£90m, removing a fair chunk of the estimated £165m received in gate fees in one foul swoop.

The situation becomes more interesting, and even critical, when one considers what is happening today with the huge increases in anaerobic digestion (AD) capacity – WRAP and the NNFCC are reporting ~2.5m tonnes capacity for plants accepting municipal waste. If all of the food waste collected from the 6m households with separate food goes to AD (which it doesn’t) this would equate to ~500 000 tonnes, so clearly there is an enormous feedstock gap needing to be filled by non-household waste.

Investment Depends On Assurance

Investment depends on assurances about feedstock and for a number of years IVC worked on contracts giving the £45-65 per tonne necessary to produce a safe and quality compost and whilst throughput was, and still is, important the quality of what was actually coming in was also important and loads would be rejected and discussions held with suppliers over quality.

Now with the AD industry expanding ferociously with their “feed me, feed me now” mantra necessitated by an absolute need for gas and with their financing typically on a precipice, they will take almost anything at any price. The consequential effect has been that gate fees for everyone in the organics recycling industry have come under massive downward pressure and with this comes the fear of rejecting loads.

An often overlooked, yet fundamental differential for organics recycling is the impact feedstock quality has on the final product. At present there are no external financial links between the two either via differential gate fees or through returns from recyclate (compost/digestate) sales, and nor is there any real system for accurately measuring and reporting rejects at any stage of the system, thus today the only incentive for improving feedstock quality is good will.

So, ironically, the success of the government’s drive for more AD combined with the natural pressure from investors to provide instant and constant returns is driving down gate fees, increasing contamination/non-target materials, and thus threatening end product quality and in turn overall market confidence to the detriment of the entire sector. If organics recycling is going to continue to play the leading role in the UK reaching its landfill and recycling obligations, this needs to change and change fast.

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