Bioremediation of persistent organic pollutants using plant liquid fermented extracts

Constructed wetlands are used worldwide to manage persistent organic pollutants (POPs) originating from domestic wastewater, with reeds (Phragmites australis) playing a key role in this process. Reeds take up POPs and sequester them within their tissues to phytoremediate the wastewater before discharge into waterways. While this process is cheap and environmentally conscientious, a major issue remains to be fully solved. Current practices require the reeds to be cut each year to ensure continued phytoremediation and these polluted plant tissues are considered an unusable waste product. Interestingly, nettle plants are commonly seen growing in reed beds and nettle has been used since the dawn of times to produce liquid fertilizer. We report a simple means to generate liquid fertilizers from contaminated reed/nettle tissues that reduces contaminating POPs levels by 87-95%, demonstrate their ability to promote plant growth and disease resistance, and detail the microbes that are likely key for this transformation.