Influence of time on carbonization and activation From Table 2, upon increasing the time on carbonization temperature range of 400-600oC for 1-2 h, the methylene blue number increased. This could be attributed to the fact that when increasing the time of carbonization, some volatile compounds which were in the inner part of particle could evaporate more with longer carbonization time. The optimum condition for carbonization and activation was 600 and 1000oC respectively for 1hr. The characteristics of activated carbon produced at these conditions were; yield of 20.36 %, bulk density of 0.509 g/cm3, ash of 6.15 % and methylene blue number of 192.6 mg/g. The activated carbon produced from these optimum conditions was used for the testing study on brewery wastewater sample.