Many plants are reducing the amount of contaminants in digestate to meet the quality requirements of PAS 110 which covers all anaerobic digestion (AD) systems that accept source-segregated biowastes. It specifies:
- Controls on input materials and the management system for the process of anaerobic digestion and associated technologies;
- Minimum quality of whole digestate, separated fibre and separated liquor
- Information that is required to be supplied to the digestate recipient.
This requirement allows for the use of digestate as a fertiliser and in land application.
MSE Hiller supply Smicon MAS filter units to the UK. These units are ideally suited for the controlled dehydration and separation of miscellaneous liquid process, waste and residue flows from industrial, organic and agricultural applications.
Not only do they provide the benefit of cleaner sludge by removal of oversize particles, they also significantly reduce wear & tear and any maintenance downtime required on subsequent plant and equipment such as pumps, pipework, mixers and macerators. The solids which comprise of any oversize material and plastics simply drop out the end of the MAS unit and can be conveyed to a skip or trailer for removal from site.
A recent trial at a major AD plant in Scotland using one of our Smicon MAS screw filter units, showed the plastics content was reduced significantly by use of a MAS unit with a typical screen size of 3mm. As a result of these trails, two units have since been installed.
Smicon MAS filter units have a low energy / power requirement (2.2kW) and can be totally enclosed. The units are suitable for either a Gravity feed or a pumped supply. Flow rates of 1 to 30 mph can be achieved depending on the sludge and solids contamination level and the solids are discharged through a compacting cone at pressure to produce a high level of dry solids typically 50 %. Screen cleaning is by mechanical means and no additional water, chemicals - coagulants / polyelectrolytes/ flocculants are needed.
