Works well only if you have an oxidant or sanitizer killing the bugs before re-using the water. Not good for operations with space restrictions. A good filtration, bio slime can clog the filters and replacements are often. Need to design with pre-filtration in mind. Minimize pit size.
Redundancy is always the safest.
Catalytic Oxidation is a combination of ultraviolet light and ozone, which is extremely effective in oxidizing organics and eliminating odors from air or water. The greatest benefit of ultraviolet light systems is that they require minimum or no maintenance as opposed to other types of ozone generators. Corona discharge ozone systems require regular cleaning of the internal plates and in many cases where the atmosphere is humid will fail altogether due to corrosion caused by the nitric acid buildup unless air dryers or oxygen generators are used. Water treated with catalytic oxidation process or ozone alone, or any of the friendly oxidizers will have less chemical residue and provide cleaner reclaim water, thereby reducing the residual odor from washing, eliminating chemical fragrance usage and an overall, more pleasing aroma left in the car after washing. Biological treatment , commonly referred to as bacteria or bugs or enzymes , combined with some form of aeration, are effective in removing odors and are safe providing they are oxidized , disinfected , or killed before re-using the water.