en 
2022-06-29
USING INORGANIC COAGULANTS IMPROVES THE CARBON FOOTPRINT
Wastewater treatment plants have the main objective to treat the incoming wastewater to meet specified discharge criteria. Different process configurations requiring different amount of resources such as energy and chemicals can be used. The selection of process configuration can also impact the amount of energy produced from digestion of the sludge to biogas.
In this study released by the Swedish environmental investigation institute, IVL, Life Cycle Assessment (LCA) has been used to calculate the environmental impact of operation of three different process configurations for phosphorus removal from wastewater. This configurations have been pre-precipitation, simultaneous precipitation and enhanced biological phosphorus removal (Bio-P) to two different effluent standards regarding total phosphorus: 1 mg P/L and 0.3 mg P/L.
Pre-precipitation and simultaneous precipitation are based on phosphorous removal by addition of chemicals in different locations along the treatment process, Bio-P is based on removal by additional uptake of phosphorus by specialized bacteria. Both iron and aluminium based precipitation chemicals were studied.
The results show that pre-precipitation gives the lowest GWP per m3 of treated water for both effluent standards. Pre-precipitation results in a higher removal of pollutants in the primary sedimentation which is positive from two perspectives: lower load on the biological treatments resulting in lower energy consumption in this treatment step and a higher methane production in the digestion process. Bio-P gives the highest GWP.
The results of this study may seem contradictory due to how the chemical industry is considered in environmental terms. Every “bio” term it appear to be “ecological”. However, an analysis in depth has shown that for the water treatment plants chemical products help in protecting the environment.
The full study is available in English for anyone interested.
If you want to get it, contact the technical direction of Feralco Iberia:
Tel. 943 653028
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