Enhancement of sludge granulation in anaerobic treatment of concentrated latex wastewater

Recently, the upflow anaerobic sludge blanket (UASB) reactor has become attractive for wastewater treatment with low energy requirement and biogas production. However, the start-up of an UASB reactor depends on the formation of granules. Therefore, this research aims to study the effect of AlCl3, CaCl2 and temperature on the granule formation process using real concentrated latex wastewater. The result shows that the optimum chemicals concentration of AlCl3 at 300 mg/l enhanced the biomass accumulation and sludge formation process. Approximately 50% of large granular size (0.5 mm < d < 0.8 mm) was obtained with a specific methanogen activity (SMA) of 0.14 gCOD/gVSS/d after 28 days. The COD removal efficiencies were gradually improved until reaching 50% at the end fermentation. Furthermore, the result shows that increasing temperature did not promote granular size. In addition, the granular sludge (R1) (positive control), crushed sludge (R2) and crushed sludge with 300 mg/l of AlCl3 (R3) was examined in 2-l UASB system. It was also found that reactor with AlCl3 supplement (R3) could provide a large granule size (d > 0.8 mm) within 35 days, whereas the large granular sizes in reactorwithout AlCl3 supplement (R2) became visible within 63 days. Moreover, this experiment found that R1, R2 and R3 could reach steady state within 40, 55 and 45 days, respectively