The Effects of Natural Zeolite on Salinity Level of Poultry Litter Compost

Authors: N. Gamze Turan

Application Keywords: Composting; Poultry litter; Salinity; Electrical conductivity; Natural zeolite

Abstract: The aim of this study was to investigate the salinity uptake by  natural zeolite when used as an ingredient during the composting process. The amounts of 5% and 10% of natural zeolite were applied to poultry litter as volume and compared with the compost made with no amendment. The results clearly showed that the salinity level of poultry litter was too high. It was found that the salinity level in the end compost decreases with increasing the amount of natural zeolite used. Salinity uptake efficiencies were 66.64% and 88.92% for end product containing 5% and 10% natural zeolite, respectively. Significantly, the addition of natural zeolite to poultry litter compost was found to have a beneficial effect on the characteristics of the end product.

Samples of natural zeolite were taken from the Rota Mining Company open pit mine in Manisa-Gordes in Western Anatolia.

Enhancement of Microbial Density and Methane Production in Advanced Anaerobic Digestion of Secondary Sewage Sludge by Continuous Removal of Ammonia

Authors: Bing Tao, Joanne Donnelly, Ivo Oliveira, Ruth Anthony, Victoria Wilson, Sandra R. Esteves,

Keywords: Advanced anaerobic digestion; Ammonia inhibition; Ion-exchange resin; Zeolite; Thermal hydrolysed secondary sewage sludge; Bacteria and methanogens gene abundance

Abstract: Ammonia inhibition mitigation in anaerobic digestion of high solids content of thermally hydrolysed secondary sewage sludge by the NH4 + affinitive clinoptilolite and a strong acid type ion-exchange resin S957 was investigated. Continuous NH4 + -N removal was achieved through ion-exchanging at both temperatures with average removals of 50 and 70% for the clinoptilolite and resin dosed reactors, respectively. Approximate 0.2–0.5 unit of pH reduction was also observed in the dosed reactors. The synergy of NH4 + -N removal and pH reduction exponentially decreased free NH3 concentration, from 600 to 90 mg/ L at 43C, which mitigated ammonia inhibition and improved methane yields by approximately 54%. Microbial community profiling suggested that facilitated by ammonia removal, the improvement in methane production was mainly achieved through the doubling in bacterial density and a 6-fold increase in population of the Methanosarcinaceae family, which in turn improved the degradation of residual volatile fatty acids, proteins and carbohydrates.

Two ion-exchanging materials, including clinoptilolite and a strong acid type ion-exchange resin S957, were evaluated for ammonium removal. Clinoptilolite with particle size of 1–2 mm was obtained from Rota Mining Corporation, Turkey.