MamaGrande: Transforming Wastewater Treatment into Biorefineries Producing Renewable/Biodegradable Plastic – Argentina

This activity developed an integrated system for a combination wastewater treatment plant and biorefinery in the town of Totoras, Argentina. By innovating with already-known components and leveraging public support, the project developed an alternative industrial paradigm that shows how climate-smart investment is also economically smart.

Fast facts:

Successfully lobbied city to pass local ordinance supporting project;
Net carbon fixation of 130 tonnes per year through local wastewater treatment for 11,000 inhabitants;
150 hectares of wastewater treatment lagoons to be converted into a biomass generation farm using public/private funds.

The problem

Climate investment is sometimes seen as a sunken investment. But by transforming sunken wastewater treatment costs into a biorefinery, and coupling environmental services with production of high-value industrial products, the climate investment equation can be changed.

The solution

This project developed wastewater treatment that incorporates a refinery for biodegradable plastics. Duckweed, a floating aquatic plant, grows rapidly on sewage and produces high-starch biomass, while cleaning the water. That starch can be used as is for animal food or fermented into lactic acid and polymerized into a renewable and biodegradable plastic. The resulting water can be used directly for animals and plants, or made potable for humans.

The local city council reviewed and approved the project, and unanimously issued a local ordinance to return any private investment in the project as paid taxes in two years. This ordinance incentivized local industry to finance it to 50%.

Helping the planet

Producing bioplastics and ethanol replaces plastics and fuels that would otherwise have been made from fossil fuels. This process of purifying wastewater also uses fewer resources than conventional wastewater treatment.

Helping people

This project also helps with food security, as the process replaces use of food crops in production of ethanol or bioplastics.

Scaling up

Once established, the biorefineries are by design self-sustaining after one to two years. The water remediation process, coupled with biomass generation, is simple and has very few biological and technological requirements. Native duckweed species are available around almost the entire world. Duckweed wastewater treatment is reported to be possible through a range of climatic conditions, making this process suitable for replication at other locations.