Food waste set to spark biological boom?

Composting operators could be set to feast on food waste as anaerobic digestion starts to enter the biological arena in a big way. We look at the current state of play in the sector and where future growth may lie

A significant rise in food waste collections could drive future growth in the UK composting and biological treatment industry, sparking demand for new infrastructure such as in-vessel and anaerobic digestion facilities. This is according to the latest nationwide research from the Association for Organics Recycling.

The state of composting and biological waste treatment in the UK 2006-7, an annual market survey, assessed data from 122 companies who between them, ran 222 composting or biological treatment sites during this period. Comparison with UK municipal waste data showed that the report captured detailed information on nearly three-quarters of municipal waste composting.

Slowdown in growth recorded
The survey found that while the industry is continuing to grow, this growth has slowed down compared to previous years. However, as more councils take up food waste collections, this could accelerate activity in the sector going forward. The total amount of source-segregated waste composted in 2006-7 was 3.6M tonnes, up a modest 5% from 2005-6, of which 3M tonnes (82%) were municipal waste.

Just under half (48%) of this municipal waste was from civic amenity sites, with a further 46% from kerbside collections. The non-municipal element, 482,000 tonnes, came from landscaping/grounds maintenance and food waste industry wastes. Meanwhile, the quantity of mixed waste undergoing biological treatment was much lower – around 138,300 tonnes of mixed waste was processed.

The survey also examined the industry’s market composition. It estimated the annual turnover of the industry at £100M – up 10% on 2005-6 – with a workforce of about 1,200 full-time employees. An estimated 40% of the total turnover is attributable to the top 20 largest firms, with individual company turnovers exceeding £1M.

The size distribution of composting sites showed that there are large numbers of medium-sized sites, with 41% of sites taking between 10,000-50,000 tonnes of waste input in 2006-7. These sites are also estimated to account for 73% of total waste composted, while only 4% is processed through smaller sites (taking less than 5,000tpa). Altogether 86% of waste is composted by the 54% largest sites taking above 10,000tpa.

Around half of all sites were found to be dedicated composting sites. A further 25% of sites were classified as farm sites, and 13% were defined as landfill sites. However, only 11% of the total waste composted was accounted for by farm sites, compared to 19% of waste composted by landfill sites.

Most popular processes
In terms of the technology and processes employed, open air mechanically turned windrow was the most common, with 79% of all source-segregated waste composting carried out using this method. A further 11% was undertaken using in-vessel composting. However, only 15% of sites surveyed were fully certified under the PAS 100 scheme – a further 34% were found working towards certification.

In 2006-7, it was estimated there was up to 1.4M tonnes of unused source-segregated waste processing capacity and about 150,000 tonnes of unused mixed waste processing capacity available in the UK. Current capacity is therefore estimated to be up to 5.3M tonnes, of which current composting accounts for 71% of annualised capacity.

Many composters also indicated that they had plans to expand capacity at existing or new sites. The vast majority of this expansion would be for source-segregated waste inputs, and 30,000 tonnes of mixed waste processing capacity due to come on line over the next five years. Total UK capacity is thus anticipated to rise to 5.9M tonnes over this period.

Where are the markets?
Looking at the markets for compost, the main product produced from source-segregated waste was soil conditioner which accounted for over 1.5M tonnes (73%) of the total products produced. The proportion of soil conditioner produced has increased in recent years, from around 60% four years ago and 71% in 2005-6. Nearly half (44%) of all composted products in the UK during 2006-7 from source-segregated feedstock were sold, with a further 31% used on the site of production and 21% distributed with no charge.

More than half (53%) of all products generated from source-segregated composting went to agriculture, followed by landfill restoration/daily cover (15%) and landscaping (12%). Agricultural end-use has more than doubled over the past four years, and operators consider this marker to offer the greatest growth potential for their business.

The majority of outputs from mixed waste biological treatment processes were either distributed with no charge, used on site of production or other sites of the producer, or disposed of directly to landfill. These outputs tend to be of lower value, and the market sector distribution reflects this, with around 70% of outputs going to landfill restoration or landscaping. In the future, there may be potential for mixed waste output to be used as fertiliser for crops intended for biomass fuel.

Looking ahead into the potential for food waste processing, the survey found that less than 1% of the municipal waste collected at the kerbside and taken on for processing was food waste. However, this is predicted to grow over the coming years. In addition, the survey found that through anaerobic digestion, 86,700 tonnes of digestate was produced from source-segregated feedstock – and more than half of this was used as soil conditioner.

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