Land spreading options for non-source segregated organics – present landbank restrictions and future possibilities
Ash, C.1, Wheeler, R.1, Whyatt, P.1 and Bullock, S.2, 14R Group, UK 2Renewi plc, UK
(free)
Pressures on reducing the amount of biodegradable waste sent to landfill continues to be a key focus
across the UK and Europe, with targets to significantly reduce volumes set out in the 1999/31/EC
Landfill Directive. Waste recyclers employ a range of processes collectively known as ‘Mechanical
Biological Treatment’ to separate fractions of waste, to reduce the portion that requires landfilling; these
processes include mechanical separation of recyclables followed by a biological treatment element
such as anaerobic digestion (AD) and/or composting of the organic fraction. Biodegradable municipal
waste accounts for around 50% of the overall composition of the mixed waste stream, however, despite
having the technology to recover these organics, options for end use are limited by legislation that
restricts its application to agricultural land.
4R Group and Renewi plc are working together to produce a thorough risk assessment of non-source
segregated organic materials that are produced at two Renewi operated MBT sites with different
biological treatment processes. The aim of this project is to obtain an agricultural end use outlet for the
treated organic output from these facilities. When spread to agricultural land in a managed way,
digestates and CLOs are valuable sources of N, P and K, as well as a range of micronutrients. The
addition of organic matter also brings significant benefit to the physical properties of soils by increasing
water retention and aeration of the rooting zone, decreasing bulk density, and enhancing microbial
activity, thus aiding long-term nutrient cycling in the soil.
