Poly vinyl alcohol dissolvable plastic packaging in household waste water

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I am studying plastics ending in water systems as part of a CPG industry analysis; there are indirect plastics like PET/PP/HDPE/LDPE intended for landfill or other disposals that are ending in water in the environment; that is one issue being examined in depth, and not what I am struggling with right now.

Some plastics are directly and deliberately ending in waste water from homes in an increasing scale (such as detergent tablets in PVOH polyvinyl alcohol wrapping for laundry or dishwashing).  The theory is that this plastic dissolves into an aqueous solution in the wash (but there is plenty of in-home use evidence with plastic residues that this is not always the case), and that during waste water treatment, after 30 days it will biodegrade to carbon dioxide and water in contact with typical water processing bacteria.  That is a fine and attractive consumer theory.  I am not so sure.

I have found two studies so far on oceanic and Mediterranean water plastic auditing that identified low levels of poly vinyl alcohol present in the waste (about 1% of total plastics in Mediterranean waters for example).  I need to understand more clearly the logic and science behind the waste water treatment aspect before leaping to any idiotic or hysterical conclusions.  I may do that anyway, but at least I'll be an informed idiot.

Please can someone help me with some basics on water treatment theory versus reality:

-  What types of bacteria in waste water treatment should help degrade PVOH poly vinyl alcohol to carbon dioxide and water?

-  Is this bacteria something that can be assumed in waste water treatment from all homes globally, or might there be gaps geographically?

-  Is 30 days contact time (to give the bacteria a chance) realistic in all cases or do some water treatments from home waste in some parts of the world try to do this function faster?

-  If PVOH has not dissolved due to low washing temperatures below specified dissolution criteria for the plastic (some can dissolve at 5°C, some PVOH is designed to need 60°C water to dissolve), does that mean the bacterial process can be interfered with, and PVOH may escape into the environment before it has been degraded by the bacteria as intended?

Thank you for any help educating me.