We all want to believe that PVA is the answer to not having to use big, bulky plastic bottles for laundry detergent. On the surface, it sounds like an amazing sustanable packaging solution. However, we need to be careful not to want to believe what we want to believe and instead rely on facts to decide what is best for our planet if we are going to protect it.

In this post, we examine what PVA (polyvinyl alcohol) is and why it's become popular in products like laundry pods and dissolvable sheets. We'll analyze a peer-reviewed PubMed study that reveals a concerning reality: 77% of PVA survives wastewater treatment plants intact. Despite being marketed as eco-friendly and biodegradable, the evidence shows PVA persists in the environment and can function similarly to microplastics by adsorbing and transporting contaminants. This research challenges the common assumption that water-soluble materials simply 'disappear' once they dissolve.

What is Polyvinyl Alcohol (PVA)?

Polyvinyl alcohol is a water-soluble synthetic polymer made from polyvinyl acetate through hydrolysis. Its unique properties—including water solubility, film-forming capabilities, and resistance to oils and greases—make it valuable for numerous commercial applications. Beyond laundry and dishwasher pods, PVA is used as a sizing and finishing agent in textile manufacturing, as a thickening or coating agent for paints and glues, and in food packaging and pharmaceuticals.

According to industry estimates, approximately 650,000 tons of PVA are produced globally each year, with production expected to increase by 4.09% annually. In the United States alone, recent research suggests that approximately 17,200 metric tons of PVA are used annually just in laundry and dishwasher pods, with about 10,500 metric tons reaching wastewater treatment plants.

Understanding Biodegradability

Before diving deeper into PVA's environmental profile, it's important to distinguish between water solubility and biodegradability. Water solubility refers to a substance's ability to dissolve in water, while biodegradability refers to a substance's capacity to be broken down by microorganisms into natural compounds like water, carbon dioxide, and biomass.

Many consumers assume water-soluble materials like PVA simply "disappear" once they dissolve. However, dissolution only changes the physical state—the chemical compounds remain in the water unless they're fully biodegraded by microorganisms.

True biodegradation requires specific conditions, including the right microorganisms, temperature, oxygen levels, and sufficient time. For a material to be considered fully biodegradable, it must break down completely without leaving persistent synthetic residues in the environment.

The Science Behind PVA Biodegradation

Recent studies, particularly a comprehensive 2021 analysis published in the International Journal of Environmental Research and Public Health by researchers Rolsky and Kelkar, provide critical insights into PVA's biodegradability in real-world conditions.

PVA biodegradation primarily occurs through microbial action. Bacteria utilize specific enzymes to degrade PVA by attacking the polymeric chain bonds. Some bacteria oxidize the tertiary carbon atoms, leading to the endo-cleavage of PVA molecules. Others, like Pseudomonas, mainly utilize PVA as a carbon source, generating hydrogen peroxide and other byproducts, including lower molecular weight PVA.

However, these biodegradation processes require very specific conditions that are rarely found in conventional wastewater treatment plants or the natural environment:

1. Specific microorganisms: The bacteria capable of degrading PVA are not commonly found in wastewater treatment plants.
2. Adaptation period: Microorganisms typically require a long adaptation period (several weeks) to effectively break down PVA.
3. Food-to-microorganism ratio: The optimal ratio for PVA degradation (0.1-0.15) differs from typical wastewater treatment plant ratios (0.25-0.45).
4. Retention time: Complete biodegradation requires longer retention times than those typically found in wastewater treatment facilities.

PVA in Wastewater Treatment Plants

The Rolsky and Kelkar study tracked PVA's journey through conventional U.S. wastewater treatment plants, revealing concerning findings about its fate. Their research shows that approximately 77% of PVA that enters wastewater treatment plants remains intact after treatment:

• About 61.2% ends up in biosolids/sludge
• About 15.7% remains in the aqueous effluent discharged from treatment plants

Conventional wastewater treatment involves several stages:

1. Primary treatment: This initial stage (screening, grit removal, and primary clarification) has minimal effect on PVA due to its hydrophilic nature, which keeps it in the liquid phase rather than binding to solids.
2. Secondary treatment: The activated sludge process in this stage has the potential to degrade PVA through microbial action. However, in unadapted sludge (the norm in most treatment plants), only about 20% of PVA is degraded within the typical 18-24 hour hydraulic retention time.
3. Tertiary treatment: Common disinfection methods like chlorination have minimal impact on PVA, degrading only about 1.5% under typical conditions. More advanced oxidation processes combining UV-chlorine treatment can achieve higher degradation rates but are rarely implemented due to cost considerations.
4. Anaerobic digestion: PVA in sludge undergoes anaerobic digestion, but studies show low biodegradation rates—approximately 10% during the typical retention period.

The researchers estimate that around 8,100 metric tons of PVA per year remain untreated by wastewater treatment plants annually in the United States alone.

Microplastics Concerns

While PVA differs from traditional plastics in its water solubility, research indicates it may pose similar environmental concerns. Traditional microplastics are tiny plastic fragments less than 5mm in size that persist in the environment, accumulate in organisms, and can carry toxic chemicals.

PVA, though water-soluble, does not fully disappear when dissolved. Instead, studies suggest that undegraded PVA can:

1. Adsorb and transport contaminants: Like traditional microplastics, PVA can adsorb dangerous chemicals including antibiotics, heavy metals, and other hydrophilic contaminants.
2. Mobilize heavy metals: Research has documented PVA's ability to mobilize heavy metals from sediments to water resources.
3. Affect aquatic ecosystems: PVA can alter gas exchanges, such as carbon dioxide exchange, potentially affecting aquatic life.
4. Concentrate up food chains: Contaminants adsorbed to PVA can potentially concentrate up food chains, similar to other polluted plastics.
5. Create foaming: When discharged into water bodies, PVA can create foaming that inhibits oxygen transfer, potentially harming aquatic life.

Environmental Impact Assessment

The environmental impact of PVA extends beyond wastewater treatment. The Rolsky and Kelkar study traced what happens to PVA after treatment:

• Of biosolids containing PVA, 50-60% are applied to agricultural lands (approximately 3,500 metric tons of PVA annually)
• About 20% are incinerated
• Approximately 17% are sent to landfills

Each disposal route presents environmental concerns:

• Agricultural application: PVA in biosolids may affect soil microbial activity, bulk density, and water-holding capacity.
• Landfilling: Landfill leachate can carry PVA into groundwater.
• Incineration: While incineration may destroy some PVA, it can produce airborne contaminants and doesn't always completely eliminate the polymer.

When comparing PVA to alternative materials, its water solubility initially appears advantageous. However, its persistence in the environment and potential to transport contaminants raise significant concerns about its long-term ecological impact.

Consumer Considerations

For environmentally conscious consumers, the findings on PVA present a dilemma. Products using PVA, like laundry and dishwasher pods, offer convenience but may contribute to environmental contamination. Some considerations for consumers include:

1. Reading product labels: Look for information about PVA content in products, though manufacturers are not required to disclose this information.
2. Exploring alternatives: Consider traditional powdered or liquid detergents that don't contain PVA films.
3. Supporting research and innovation: Encourage companies to invest in truly biodegradable alternatives by choosing products from companies committed to environmental research.
4. Responsible disposal: While proper disposal won't eliminate PVA's environmental impact, following manufacturer guidelines for product disposal is still important.

Future Directions

The growing concern about PVA's environmental impact has spurred new research and innovation:

1. Improved PVA formulations: Researchers are exploring modifications to enhance PVA biodegradability under real-world conditions.
2. Alternative polymers: Development of new, truly biodegradable polymers that maintain PVA's beneficial properties without its environmental persistence.
3. Enhanced treatment technologies: Research into cost-effective advanced oxidation processes that could better degrade PVA in wastewater treatment.
4. Regulatory developments: Potential for new regulations requiring testing and labeling of PVA-containing products based on real-world biodegradation rates.

Conclusion

The evidence suggests that PVA, despite being water-soluble and theoretically biodegradable, does not fully degrade under typical real-world conditions. Approximately 77% of PVA remains intact after wastewater treatment, entering the environment through water discharge or biosolids application.

While PVA differs from traditional plastics, it shares concerning characteristics with microplastics—particularly its ability to persist in the environment and transport contaminants. These findings challenge the marketing of PVA as an "eco-friendly" alternative and highlight the need for greater transparency about its environmental impact.

However, on the positive side, PVA allows laundry brands to not use giant plastic bottles, which lowers the overall amount of material used in their packaging. My issue is the fact that those bottles can be recycled.

We will continue to seek new research on the topic and if you have research to the counter, please provide it and we will consider updating this post.

To us, sustainability is somewhat of a higher calling and we need to do what is best for the planet, not just what sounds good or what will sell.

We believe that in short time, what is actually best for the planet will lead to you selling millions (or billions) in revenue and taking shortcuts can backfire. So do your research on what is actually good for the planet and the dollars will follow from a more and more educated consumer base.