Effect of the clay mineral zeolite on ammonia inhibition of anaerobic thermophilic reactors treating cattle manure

The impact of ammonia nitrogen concentration and zeolite addition on the specific methanogenic activity of granular and flocculent anaerobic sludges

“…This was probably due to the fact that zeolite acted as an ion exchanger reducing the concentrations of free ammonium and in turn the concentration of ammonia nitrogen. [21,22,25,36,37] Similar behaviour was observed in the anaerobic digestion process of synthetic wastewater using digested piggery sludge as inoculum. This process was also favoured by the addition of zeolite at doses of between 0.05 and 0.30 g/g of VSS, the optimum value being 0.10 g/g VSS.…”

“…[21] In thermophilic anaerobic digestion of cattle manure, zeolite addition was capable of reducing the inhibitory effect of free ammonia. [22] Cintoli et al [23] used natural zeolite for the pre-treatment of piggery wastewater and ammonia concentration decreased from 1500 to 300 mg/L reducing the toxicity towards anaerobic microbial population and improving the performance of a UASB reactor treating this waste. Milan et al [24] studied the application of zeolite doses in the range of 0.2-10 g/L in batch anaerobic digestion of piggery waste, obtaining the best results at doses of 2-4 g/L .…”

Factors influencing the degradation of garbage in methanogenic bioreactors and impacts on biogas formation

“…Biological processes in sequential anaerobic, aerobic/anoxic, or anaerobic multi-compartment systems include nitrification/denitrification and anaerobic ammonia oxidation (Baloch et al 2006;Agdag and Sponza 2008;Bernet and Béline 2009). Addition of clay (as a mineral supply and for biomass retention), activated carbon (for sulfide removal and biomass retention), carbon fiber textiles (for biomass retention), or FeCl 2 (for sulfide removal) and increasing hydraulic retention time (for biomass retention) are also effective for counteracting ammonia inhibition (Borja et al 1996;Hansen et al 1999;Sasaki et al 2011a). Magnesium and calcium were shown to be somewhat antagonistic to ammonia inhibition (McCarty and McKinney 1961).…”

Effect of particle size and doses of zeolite addition on anaerobic digestion processes of synthetic and piggery wastes

“…However, conventional digesters used in rural areas must be operated at retention times higher than 20 days in order to achieve adequate organic matter removal efficiencies and prevent the washout of microorganisms. The increase of wastewater anaerobic process efficiency by using natural and modified zeolites has been pointed out by several authors [5,6]. The adequate doses of natural zeolite have also been studied [7].…”