The behaviour of cyanide in a landfill and the soil beneath it

Abstract

The behaviour of cyanide in a landfill and the soil was studied because at several locations in the Netherlands, heat treatment waste from metal processing firms, containing cyanide, was dumped in codisposal with domestic waste. Experiments were set up to study the behaviour cyanide under controlled conditions, with six columns of 110 cm length and a diameter of 18 cm. The columns were filled with a sand layer, on top of which a layer of ground domestic waste was placed. A layer of 25 g of cyanide was embedded in the waste. Special attention was given to the influence of the location of the cyanide-containing waste in the waste layer and the influence of the groundwater level on the behaviour of cyanide. The results indicate that 4-22% of the cyanide leached out of the column as free or complex cyanide, while 4 to 11% of the added cyanide remained in the column, probably as Prussian blue. Between 72 and 82% of the cyanide was converted, mainly to ammonium and organic nitrogen compounds.