The initial start-up of anaerobic biochemical reactor may spend many months even a year to develop granular biomass

which is regarded as a obstacle affecting widespread application of anaerobic process.Self-immobilization of microbes in anaerobic biochemical reactor may be effectively enhanced by adding proper polymers during the period of initial start-up.The characteristics

dose and way of addition showed significant influences on the methane-generating activity

and settling performance of anaerobic microbes. The objectives of this study are to evaluate the feasibility of decreasing the overall time required to form sludge granules with the aid of adding polyquatemary salt into anaerobic biochemical reactor

to determine the optimum way of addition and to quantify the dose.Sixteen biochemical reactors were seeded with anaerobically digested biosolids. Anaerobic biodegradability of polyquatemary salt was measured by the method of biochemical methane potential(BMP).The effects of polyquatemary salt at different concentrations on special methane-generating activity(SMA) of anaerobic microbes were investigated by using anaerobic toxicity assay(ATA).The results showed that polyquatemary salt can exert a positive impact on self-immobilization of anaerobic microbes.The highest SMA of anaerobic microbes appeared at 5—10mg8226;L-1(polyquatemary salt concentration).The settling performance of sludge increased as polyquatemary salt dosage was increaced

but the phenomenon of sludge floating occurred at 30—40mg8226;L-1. It was recommended that polyquatemary salt was added into anaerobic biochemical reactor during start-up at 9—10d intervals and the most optimum concentration for the granulation was from 10 to 20mg8226;L-1.