The Portagester (Bioplex) Anaerobic Digestion Process
The following is our summary of our understanding of the Portagester. Please, refer to the supplier’s site at http://www.safe-waste.com for verification and full details.
The 'Portagesters' which give their name to process, are skip or lorry mounted units into which the predominantly organic solid waste to be digested is packed.
The Portagester is then filled with recycled liquor from static liquid digesters.
The wastes in the Portagesters undergo a 3-day thermophilic digestion phase, before the liquid is drained from the Portagester and transferred to the static digester tanks to undergo a further anaerobic 30-day digestion.
After this second stage of digestion the remaining solids are removed and sent for further processing/treatment. The nature of the further processing needed is dependent upon the original waste feedstock.
Apparently, for a compost or soil conditioner product this may comprise drying, palletising, maturation and packaging for market. The liquid fraction generated during the further processing is also re-circulated to the Portagester.
The biogas produced provides energy to run the plant and can be used to fuel a Combined Heat and Power (CHP) unit.
The method is said to be good for treating odorous organic waste. (Which we presume means it could otherwise be odorous while being treated. Ed)
The process has claimed benefits over traditional AD systems. In principle the assumed substantial retention of most of the the solid fraction in the Portagester might well tend to reduce the blockages which have plagued many AD plant start-ups.
A reduction of build-up of nitrates and/or crystallisation in the tanks is also cited.
This is a fairly new technology to the waste industry (about 5 years with world-wide patents in 2004 is indicated on the Environment Agency web site). The system has received financial support from the UK Government Department, DTI and ADAS. The process is also reported here as part of the UK Waste Improvement Project (WIP).
Reference plants have been installed as follows:-
- R&D demo system in Hampshire;
- Demonstration system in Northumberland;
- Working commercial plant in Durham.
For information contact the supplier’s web site.
Portagester System should now be known as the Bioplex System
All those interested in the Portagester need to be aware of new information of which we have become aware. Please read on.
We have recently received an email from Burdens Environmental who sent us of the following information, which is duplicated here as forwarded in their email:-
As you may have gathered the patented Bioplex Process uses modular anaerobic digester's, which can hygienically treat waste material in less than three days.
Thermophilic fermentation (the first stage of anaerobic digestion -acid phase hydrolysis) is used to pasteurise the feedstock and naturally separate it into solid and liquid fractions. The digesters (sometimes known as Portagesters) can be mobile or static.
The screened liquid is used as a liquid fertiliser and/or for second stage anaerobic digestion. The anaerobic digester produces methane rich biogas, which can be used in a boiler or a combined heat and power (CHP) generator.
In a fully operational unit, the heat generated by the boiler and/or CHP generator can help to keep the process at the correct temperature and minimise the energy used on site or elsewhere.
The solid fraction is relatively odourless and can be safely spread onto farmland or aerobically composted for at least 18 to 21 days to comply with regulations. The composted material is an excellent natural slow release fertiliser and growing medium.
The whole process can be operated to EU and UK ABPR standards and is at least carbon neutral and may be classed as "Carbon Capture". The attached documents show independent research results on small scale plant growth trials done a few years ago and an example of our licensed technology in Germany, Austria and Switzerland."
Currently we are installing plant for the Home Office and various private clients including waste companies, the patented process is referred to on your web site as the "Portagester" however this is related to a now defunct agreement with a company called Safe-Waste.
We are in the process of re-vamping a brochure and updating the web site. In the mean time we can supply contact details. We also have quite a considerable amount of reference and published material on AD is this is of interest to you?
Business Development Director
Burdens & Bioplex Ltd
0870 600 6068