Brown Coal reduces Slurry Emissions - Basic Investigations of the Reduction of Emissions from Slurry through Treatment with Fine-Grain Brown Coal

Abstract

Fine-grain brown coal from the Lausitz region has been tested in the la- boratory at dosages of 3 and 5 mass-% as an alternative to swimming layers of slurry and straw. Three series of trials were carried out using slurry with dry matter contents (DM) common in practice: cattle slurry with DM = 5%, 7%, and 8.9% as well as pig slurry having a DM = 5.2% and 7.6% Together with floating slurry particles, fine-grain brown coal forms dense swimming layers, which cause a drastic reduction in odorant emission. In cattle slurry stored under undisturbed conditions, the reduc- tion amounted to approximately 70% and, after homogenizing, to 90% to 98%. In pig slurry, a 92% to 98% reduction was achieved, both before and after homogenizing. The addition of brown coal reduces the pH-value of the slurry by about 0.2 to 0.3 units and NH3 release by up to 30%. The treatment of pig slurry with fine-grain brown coal improves the con- ditions for effective solid-liquid separation into an easily conveyable liquid and a well-transportable solid with high contents of nutrients and humin. Investigations regarding the use of the large humin content of this brown coal for the long-term formation of humus remain to be carried out. In addition, questions concerning process engineering and the economic efficiency of slurry treatment with brown coal still need to be answered.