Overloading can either be ...

Overloading can either be due to excessive flow, excessive organic load, or both. There could be several reasons for this. Here are a few: (i) inadequate design - for flow or organic loading (ii) power outages - might cause some or all aeration, pumping and mixing systems to go offline, leading to transient overload (iii) unmetered industrial loads (iv) absence of online sensors and meters to provide real time, or advance warning of loads (v) lack of combined sewer overflow or diversion programs for extreme weather events - e.g., wet weather flows, monsoon rains, etc, and sometimes (vi) weak operator training & certification programs