Effective urine treatments require source removal, odor removal, and stain removal. Sometimes this happens with one product or a few companion products along with efficient extraction processes. Injecting bacteria and enzyme treatment as the last step will finalize source removal in the pad level of the carpet. Special hydrogen peroxide treatments will remove the stains left in the carpet over a few hours for nylon and wool carpet. Urine does not stain polyester carpets so the entire extraction process will remove any prior discoloration.
Source removal goes a long way in removing odor but is primarily predictive of future odors. Acidic solutions will neutralize alkaline salts enough for ammonia odors to be neutralized. Ammonia is the primary alkaline salt formed from multiple urine deposits. Ammonia has a pH around 12 which off-gasses with a pungent and familiar odor. Once the pH of ammonia drops below 9 pH, the odor readily dissipates.
Odor removal benefits from an odor encapsulate, which neutralizes the volatile organic compound malodors on contact. This works based on the molecular match. If the odor molecules are more than the odor encapsulate molecules then the odor will not be totally removed. Typically odor encapsulates are formulated with compatible synthetic fragrances which sometimes obscure the end result of odor removal. A few odor encapsulates have no fragrance which makes it apparent when enough has been used to remove the odor.
Fragrances can temporarily cover the malodor while other processes finalize source removal. Sometimes formulas rely on a strong fragrance to cover the odor for a longer period of time. Careful selection of the fragrance is essential so that the cleaner does not replace the unpleasant urine odor with a strong fragrance that may also be obnoxious.
In short, chemical and extraction technology has developed to the point where most urine treatments can be approached with the combination of a chemical solution and an efficient flushing extraction system.