Centrifugal blowers being used in exhauster applications(also referred to as vacuum systems) generally operate the same as aeration systems, but they have to be a bit more durable to handle the "dirt" being sucked through it.  High speed turbo blowers may be replacing centrifugals in aeration applications, but they cannot be used effectively as exhausters due to the chance of dirt & moisture getting inside them.  Even PD blowers are much less tolerant of moisture & gas, so they are not used very often in LFG or vacuum systems.  And when a vacuum system fails, it can be devastating!  

A few years back, a national vacuum system supplier/manufacturer had reported breakdowns of a couple of centrifugal blowers(exhausters) in a large San Francisco installation. The exhausters were part of an extensive vacuum system used by the 7 largest rental car agencies. My job was to rebuild 3 of the FAB exhausters on site and inspect the remaining 6 motor/exhauster vacuum systems to verify proper installation and design operation. 

The rebuild consisted of replacing shafts, impellers, bearings, & seals, re-assembly, installation,  connection to the system piping, shaft re-alignment, and vibration & temperature data collection.  We also conducted numerous performance tests of the vacuum system to verify each 8, 12, & 24 drop vacuum system was in accordance with manufacturer's design pressure(suction) and volume. There were many air leaks to be stopped and wand hangers to be adjusted/modified for air noise.  Although it took us 10 days, we completed the repairs, solved the performance problems, and generated a detailed report all to the customer's satisfaction. 

The machine failures were caused by improper installation and to some extent, wrong operational procedures. The equipment will only do its job if it is operated within the manufacturer's recommended procedures.  The operators did not have the proper training to prevent this catastrophic shutdown.   Invest in operator training, it will save you money!