Wastewater Treatment Plants as Biorefineries of the Future

With the dramatic changes brought about by climate change and increasing global population, countries are turning more towards sustainable energy and renewable materials, in order to keep up with the energy demand yet still be able to protect the planet from further damage.

It is widely believed that wastewater treatment plants will play a more significant role in the coming years because of their capacity to convert sewage sludge into a variety of products that can supply several industries. They can someday become biorefineries that supply everything from biogas for energy, fertilizers for agriculture, to biosolids-based bricks for housing.

Organic matter in wastewater contains compounds such as fatty acids which can be converted to useful chemicals that can have wide-ranging commercial applications. A project in Sweden is exploring the possibility of extracting these fatty acids using membrane bioreactors to produce acetic acid and hydrogen. According to Mohammad Taherzadeh, Professor in Bioprocess Technology at the University of Borås, Sweden, “We can develop a platform so that the treatment plants can be transformed into refineries where different chemical substances can be extracted and used to produce different types of materials. Fatty acids are a kind of intermediate product.”

The fatty acids are important for several petrochemical and biological processes because it has similar functions to sugar, which supplies energy for microorganisms that convert organic material to energy. Fatty acids can therefore be used to produce other products such as bioplastics and butanol.

Bioplastics are derived from plant-based material, whether wholly or in part. Starch and cellulose are two of the most common renewable components used to create bioplastics. These materials typically come from corn and sugarcane, but it can also come from refinement of fatty acids from biosolids. Bio-based plastics are better that the more common petroleum-based polymers because they are designed to biodegrade.

Butanol, a type of biogas, can be used to power cars and trucks. It can be harnessed to produce electricity. This electricity can provide power to the plant and any excess can be returned back to the power grid, giving cost-savings for the wastewater treatment plant. This helps reduce its carbon footprint by relying less on fossil fuel-based energy sources.

Other applications planned for these biorefineries are with the use of carbon to remove nitrogen and phosphorus from the sewage sludge, to prevent spillage into the waterways causing environmental hazards, such as eutrophication which leads to algal blooms.

Agricultural farmlands have already reaped the benefits of using biosolids products for their crops for many years. The biosolids they use are a much more affordable alternative to commercial chemical fertilizers and have the added benefit of having organic nutrients that can sustain plant growth. These biorefineries will never have a shortage of sewage so they can continuously supply farmers with organic fertilizers.

The idea that wastewater treatment facilities will be the future biorefineries is no longer that far-fetched. A lot of biosolids based products have been successfully manufactured in these plants which have the potential for numerous applications. As more uses are developed from the processing of biosolids, the function of treatment plants will expand, making it a sustainable and environmentally sound solution for the future.

If you are a municipality in Ontario and in need of a biosolids management solution, please feel free to contact us at 1 (877) 479-1388.

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