Amendment of Livestock Manure with Natural Zeolite-Clinoptilolite and Its Effect on Decomposition Processes during Composting

Abstract

The aim of study was to investigate the effect of amendment of cow manure with natural zeolite-clinoptilolite and hydrated lime on decomposition processes over the period of 90 days. Two static piles of amended substrates were constructed consisting of cow manure with an addition of bulking material (2.5% by weight): (1) manure mixed with zeolite (S1); manure mixed with zeolite and lime (S2). Third amendment-free pile served as a control (C). During the experiment, pH level, temperature (T), dry matter (DM), ash, organic matter (OM), C/N ratio, ammonia nitrogen (N-NH4+) and total nitrogen (Nt) were determined. We also determined the counts of total coliform and faecal coliform bacteria and faecal streptococci as indicators of the hygiene level of compost. A significant increase (p < 0.001) in temperature to 53 °C was observed in S2 compared to C. In S2 we observed a significantly reduced release of N-NH4+ from the composting substrate compared to C (p < 0.05). The significant differences were in Nt content in C and S2 (p < 0.001) and between S1 and S2 (p < 0.05). The concentration of Nt increased and caused decrease in the C/N ratio. The content of Nt in the substrates with zeolite increased by 44% in S1 and 45% in S2 compared to C. The differences in counts of coliform and faecal coliform bacteria between C and S2 were significant (p < 0.001). This experiment showed that amendment with zeolite and lime decreased nitrogen losses during composting and indicated sorption effects of zeolite.