SUPLEMENTING DIGESTER FEED WITH PULPED ORGANIC WASTE USING DEWASTER® – TECHNOLOGY
Keith Panter*, Mads Prag Roesen
Ebcor Ltd, UK –
NLM Combineering, Denmark
Erik Ulnits, EWOC. Denmark
(free)
Many Danish cities have been sorting household waste since mid 1980s. The objective was to use the digestate as a fertiliser for agricultural purpose as well as the biogas energy for CHP. This idea has not been a success mainly because the household sorting quality does not suit biogas plants, which need a product free of plastic, metals and other unwanted items. A number of tests have been conducted at Aalborg, Holbæk, Hamburg, Århus, and Odense on the Dewaster® concept. It was a goal of the project that the level of heavy metals and other harmful substances in the biopulp should meet the requirements in the Danish legislation at the time of the study.
The Dewaster® – system divides the waste into a biomass fraction and reject fractions. A common observation from all waste types is that the biomass fraction looks the same and has a dry matter typically between 25% and 30 %. The pulp is easily transported at <20%DS. If made on the same site as the digester the pulp can be blended with other thinner materials before digester feed.
An economic evaluation has been carried out and this is described in the paper. The implications for the UK Waste Industry are then discussed. Dewaster® technology has been shown to be an effective way of producing a clean and easily biodegradable fraction of organic waste. It enables an operator to achieve about 25% recycling rate with mixed waste and can also treat more specific biowaste.
KEY WORDS Dewaster®, Biowaste, Biodegradable fraction, Organic Waste Extraction, Refuse Derived Fuel.
