Background
The EU Landfill Directive is driving Local Authorities to reduce the amount of biological waste sent to landfill together with a new interest in the "Green Agenda". The recovery of materials is also encouraging Local Authorities to recycle more. Although many Local Authorities are providing source separated collection services, enabling more to be recycled, there remains a residual waste that still requires treatment. Mechanical and Biological Treatment (MBT), which has been extensively and successfully deployed in Europe, is now seen as the solution for many Local Authorities.

MBT
MBT consists of a mechanical phase (principally separation) and a biological phase (principally composting). However, by design of the configuration and process of both the mechanical and biological phases, MBT can be deployed to achieve varying objectives for the customer.

Resource Recovery
Where markets make recovery of material economic, the mechanical setup of a plant can be designed to have a high focus on resource recovery. Biological treatment is still required, firstly to make the mechanical separation more efficient and then to treat the residual organic fraction, reducing the organic content prior to sending to landfill.

Biostabilisation
The UK markets are still developing for recovered materials.Biostabilisation is required if heavy fines are to be avoided for exceeding landfill allowances. Simplified mechanical processes will prepare MSW for biological treatment and will separate and recover materials with a high market value. The focus of the process is on the biological element of the process. The aim of the biological process is to reduce the waste's ability to produce methane. This is achieved through intensive composting. The residual waste that is finally sent to landfill has to be tested against the UK's BM100 test to verify its reduced biological activity.

Solid Recovered Fuel
The UK currently has a limited market for Solid Recovered Fuels (SRF). However, where markets exist, residual waste can present a sustainable alternative to fossil fuels and there is increasing interest in MBT deployed with its focus on SRF production, with residual waste being able to produce a fuel of a calorific value between 11-14 mJ/kg. The mechanical process includes metal extraction and ballistic separation to remove ceramics and glass. The focus of the biological process initially encourages composting to generate temperature, followed by high levels of aeration to drive off water and hence deliver an SRF with the highest possible calorific value.

Agrivert and Mechanical and Biological Treatment
This technology has now been successfully deployed in a number of MBT plants across Europe. Agrivert can provide tailored solutions to meet the customer's individual objectives using proven technology. We recognise that the market for recovered material is swiftly changing and the "Green Agenda" is also incentivising technology innovation and new legislation. Our plants can be designed to be flexible for the future to allow facilities to be operating consistently at the forefront of technology and exceeding the expectations of our customers.