Biodegradable and flushable properties:
Biodegradation of PVOH is the process by which microorganisms such as bacteria and molds secrete extra-cellular enzymes that chemically break down the polymer into smaller molecules. These in turn are degraded to carbon dioxide and water.
At least 55 species of microorganisms have been shown to degrade or take an active role in the degradation of PVOH. The degradation pathway is via oxidation reactions by the enzyme secondary alcohol oxidase, followed by polymer chain cleavage and the gradual formation of acetic acid. Acetic acid rapidly degrades to carbon dioxide and water.
Many studies have shown that PVOH will biodegrade in wastewater treatment facilities, in compost and in soil provided these environments contain acclimated microorganisms. It has also been shown by various researchers that PVOH is non-toxic and non-inhibitory. Some of the studies showing its extremely low toxicity include those on fish and daphnia – those conducted in accordance with the Fish Pesticide Acute Toxicity Test guidelines issued by EPA show that no mortality or response indicative of toxicosis or physiological stress was observed. Furthermore, the metabolism of acclimated microorganisms was not inhibited which means that the presence of PVOH contributes to effluent chemical oxygen demand (COD) in wastewater treatment facilities. It is important to note that the other components of MonoSol’s PVOH products, such as the plasticizers, are far more readily biodegradable than the PVOH polymer itself.
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