Full scale experience with the BIOCEL process

Abstract

The BIOCEL process is a mesophilic dry anaerobic batch digestion system for solid organic wastes. In the BIOCEL process organic solid wastes, such as source separated organic fraction of MSW (biowaste) is converted into enriched compost and biogas. In the process net energy production is achieved by converting the biogas to heat and power with a heat-electric power production unit. In September 1997 the first full scale plant is started-up in Lelystad, The Netherlands. This plant is processing 50,000 tons of biowaste (organic fraction of MSW from source separation) per year. The plant has a net energy production and therefore contributes to prevention of CO2 emissions from fossil fuels. In the BIOCEL-system the several compost fractions are produced with a "wet" separation process. During the wet separation sand and contaminants are removed. An important aspect of compost quality is the absence of several types of pathogens. It appears that anaerobic digestion with the BIOCEL-process results in complete inactivation of several important groups of plant and animal pathogens. The mechanism that causes the inactivation is not yet fully understood, but the relatively high Volatile Fatty Acids concentration during the first two weeks of the digestion process might presumably be the key factor.