The attainable loading potentials of anaerobic sludge bed systems are strongly dependent on the growth of granular biomass with a particular wastewater. Experiments were conducted to determine the effects of high salinity wastewater on the biological and physical properties of methanogenic sludge. Sodium concentration of 5 g/L and 15 g/L were added to the influent of upflow anaerobic sludge bed (UASB) systems. After 100 days of operation, the methanogenic activity, extracellular polymeric substances (EPS), and granular strength were analyzed. The results show a high removal of organic matter but with accumulating propionate concentrations in the effluents. Meanwhile, wash-out of active methanogenic biomass in the effluent of the reactors was observed, likely as a results of the high Na+ concentrations. The rinsed biomass was characterized by a considerable specific methanogenic activity (SMA) on acetate, propionate and hydrogen as the substrates. On the other hand, results show that the SMA evolution was not affected by high salt concentrations. Also the amount and composition of extracellular polymeric substances (EPS) were similar in all sludges. However, results clearly show a sharp drop in the granule strength as a results of high Na+ concentration.

The major effect of Lactobacillus inoculation on laboratory cassava (Manihot esculenta Crantz) silage was a change jiom a heterofermentative pattern observed in natural silage to a homofermentation. Small amounts of starter culture ( I % v/w) were required to produce a high level of lactic acid (> 28 g kg-D M ) and to reach a pH of at least 4. The Gompertz model was used to evaluate the effect of inoculation level on the lactic formation based on kinetic criteria. Also an empirical pH-lactic acid correlation was proposed to monitor the progress of ensiling, based solely on pH measurements. The simulation model may be used to improve guidelines for silo safety and to evaluate the effect of lactobacilli inoculants.

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