Environmental footprint

Environmental footprint

One of INCOPA’s roles is to quantify the environmental impact of coagulants. It is well known that municipal wastewater treatment plants consume energy in their processes, but also have a potential to produce energy in the form of biogas. There are a number of “standard” process solutions when treating wastewater depending on its quality, treatment requirements, available space and assessment on what is a good solution.

Life Cycle Analysis of different Wastewater Treatment Plant Processes

Pre-Precipitation with coagulants has the lowest carbon footprint, while Biological Phosphorus Removal has the highest.

The Swedish Environmental Research Institute (IVL) has published in December 2020 A study, co-funded by INCOPA, on Life Cycle Analysis of different Wastewater Treatment Plant Processes. This LCA compares the environmental impact of treating wastewater:

• to two levels of effluent quality: total phosphorus concentration of 1 mg P/L and 0.3 mg P/L
• in three process configurations: Pre-Precipitation, Simultaneous Precipitation and Biological Phosphorous Removal.

The incoming water quality was the same in all scenarios. Automatic process control in the models was used to achieve similar treatment results for the different processes. The more stringent the phosphorus removal limits, the higher the carbon footprint. Pre-Precipitation has the lowest carbon footprint, while Biological Phosphorus Removal has the highest.

Life Cycle Assessment (LCA) for Coagulant Production

The carbon footprint of coagulants ranges from 40 to 120 g CO₂ eq./mol Fe³⁺ or Al³⁺, an impressively low value.

In 2023, INCOPA updated its Life Cycle Assessment (LCA) for coagulant production. The study covers the entire process from the production of raw materials to the point where the coagulants leave the factory gate, known as a cradle-to-gate assessment.

Carbon footprint assessment of chemical and biological phosphorus removal

In wastewater treatment plants, chemical phosphorus removal offers a more sustainable approach than biological treatment, and also allows to achieve energy neutrality.

The Carbon Footprint Assessment of Chemical and Biological Phosphorus Removal [link] report aims to evaluate the environmental impact of different wastewater treatment processes. It focuses on comparing the carbon footprints of chemical and biological phosphorus removal methods and explores the potential for achieving energy neutrality in wastewater treatment plants.

Chemical phosphorus removal reduces climate impact by lowering electricity consumption and increasing biogas yield.

Achieving energy neutrality in wastewater treatment is more feasible with chemical phosphorus removal due to reduced electricity consumption and enhanced biogas production.

To meet stricter phosphorus limits (0.3 and 0.5 mg/l), wastewater treatment plants must undergo additional energy-consuming steps such as sand filters, which ultimately increase the overall climate impact.

This report provides valuable insights for wastewater treatment plants aiming to meet stricter effluent limits and improve sustainability.