r unit sizes and Type H Gear unit dimensions T B3-VH-13-A Bevel-helical gear reducers B3

Flender/Flender Gear Units/Bevel-helical gear reducers B3

on. Automated process control has to be implemented toge ther with optimised process control as discussed in Section 4.6 to maximise energy savings. 5.6.2 Replacing Existing Surface Aerato rs with More Efficient Systems Higher aeration energy savings can be achieved by replacing the existing slow speed surface aerators with more efficient systems. Feasible options to consider are given below. Fine Bubble Diffused Aeration Fine bubble diffused aeration has up to three times higher oxygen transfer efficiencies than the existing slow speed surface aerators. Some equipment manufacturers report overall efficiencies as high as 6 to 7 times more with new blower and membrane diffuser technologies. Major modifications to the existing plant will be required to install fine bubble diffus ers at the bottom of the bioreactor, air pipes and 5-1 blowers. The costs of the modifications as wells as the logistics will need to be carefully considered since there is only one bioreactor lane at the plant. Hybrid Aerator/Mixer with Diffused Air The latest hybrid aerator technologies that are comb ined aerator/mixer utilise diffused air provided by high efficiency blower. The aerator resorts to mixing mode when the blower is turned off and this dual functionality provides more flexibility than surface ae ration or fine bubble diffused aeration alone. One of the proprietary aerators supplied by Aeration Industries International is reported to have higher oxygen transfer efficiencies than fine bubble diffused aeration due to the unique design that forces air down through the shaft and exits in high velocity stream of fine bubbles that are evenly dispersed throughout the entire aerobic tank. Hybrid aerators of the type supplied by Aeration Industries International have simple designs and are easier to retrofit at plant like JP Marais which was designed for surface aeration than FBDA and would thus be the more feasible practical option. Dual Impeller Su