Odour reduction of manure through addition of boracic charcoal

Odours released during the land application of manure results from different gases released from the liquid phase. These gases do create objectionable odours in the vicinity of the land-applied manure. In order to reduce the intensity of odour during manure application, we investigated the effectiveness of combining Borkohle with manure during land application. Boracic acid is widely used as a flame retardant in cellulose insulation. During demolition of existing buildings, this insulation is sorted into its own residual waste fraction. The cellulose fibres are extracted and pelletized on site. Subsequently, the pellets are charred in a pyrolysis furnace. The resulting Borkohle – charcoal containing boron in various compounds - can be used as a soil enhancer and provides the trace element Boron to the fields. Furthermore, Borkohle provides long-term storage of carbon in the soil. Initial trials of combining boracic charcoal with manure additionally showed that odour emissions seemed to be significantly lower when manure was combined with Borkohle. This work presents methods to quantify the odour reductions resulting from the addition of Borkohle to manure as well as first results. Parameters like the influence of the amount of charcoal added and exposure time have been investigated. Charcoal was added at concentrations between 5 and 250 g L-1. While applying typical amounts of charcoal, a reduction of odour concentration of up to 85% was observed. A positive correlation between odour reduction and the amount of charcoal added was observed. Charcoal has a negligible effect when exposure times are less than 30 minutes.