Preliminary results of the Environmental and Socio-Economic Assessment

An integrated assessment of the environmental and socio-economic impacts of the innovative technological solution of demEAUmed project has been undertaken by demEAUmed consortium under the leadership of the Sustainability Division of LEITAT.

The methodology applied in the assessment is based on the Life Cycle Assessment (LCA), the Life Cycle Costing (LCC) and the Social Life Cycle Assessment (S-LCA). The primary results of the LCA and LCC have been obtained and analysed involving four technologies: the Electrocoagulation-Flotation technology, the Photoelectro-Fenton technology, the VertECO technology, and the Electrochemical Ozonation technology.

Potential environmental savings of greywater recovery and reuse

Regarding the environmental life cycle assessment (LCA), the results show that these four technologies have achieved important environmental impact savings thanks to the greywater recovery and water reuse. The greatest environmental impact savings are achieved for the case of Electrochemical Ozonation technology. Here, in 6 out of 9 impact categories, the environmental savings due to water recovery and water reuse are the highest (from 5% up to 123%, depending on the impact category studied (see Figure 1). Thus, it means that the environmental impact contributions associated to the Electrochemical Ozonation are completely offset by the benefits of greywater recovery and reuse.

Figure 1. Environmental impact contributions of Electrochemical Ozonation technology and environmental savings of recovery and reuse greywater by using Electrochemical Ozonation process.

The second technology with greatest environmental impact savings is VertECO technology. For the ozone depletion impact category, the environmental impact contributions are lower (59% less) than environmental benefits reached by greywater recovery and reuse. For the rest of the impact categories, the recovery of greywater provides environmental benefits of around 43%, on average, compared to the environmental impact contributions associated to VertECO (see Figure 2).

Figure 2. Environmental impact contributions of VertECO technology and environmental savings of recovery and reuse greywater by using VertECO process.

Thirdly, the Electrocoagulation-Flotation has environmental impact savings higher than environmental impact contributions only for the ozone depletion impact category (32% superior). The recovery of greywater result, on average, a 24% of environmental impact savings for the other impact categories evaluated (see Figure 3).   

Figure 3. Environmental impact contributions of Electrocoagulation Flotation technology and environmental savings of recovery and reuse greywater by using Electrocoagulation Flotation process.

Finally, the recovery of greywater has the lowest positive effect on Photoelectro-Fenton technology. For all the impact categories analysed, it was found that the environmental impact contributions are higher than environmental impact savings. The environmental benefits go from 43% (mineral, fossil and renewable resource depletion) to 17% (freshwater eco-toxicity), with an average of 28%, considering all the impact categories analysed (see Figure 4).   

Figure 4. Environmental impact contributions of Photoelectro-Fenton technology and environmental savings of recovery and reuse greywater by using Photoelectro-Fenton process.

Main environmental impact contributions of demEAUmed technologies

Most of the environmental impact contributions are incurred during the operation stage, due to the energy consumption needed to run up the technology. This is the case of the Electrocoagulation-Flotation technology (see Figure 3) and Photoelectro-Fenton technology (Figure 4). In both technologies, for all the impact categories analysed, the main environmental impacts are related to electricity consumption. The environmental impact contributions of electricity in Electrocoagulation-Flotation are higher than 98% (Figure 5). For the Photoelectro-Fenton (Figure 6), the environmental impact contribution of electricity ranges from 65% (mineral, fossil and renewable resource depletion) to 94% (ozone depletion). 

Figure 5. Potential environmental impacts of operation stage of Electrocoagulation-Flotation technology

Figure 6. Potential environmental impacts of operation stage of Photoelectro-Fenton  technology

In the case of VertEco technology, the main environmental drawbacks are generated in the construction stage (see Figure 2), due to the transportation (Figure 7) of the VertEco structure (a heavy structure made of stainless steel, mainly) from Austria (where Alchemia Nova is located) to the SAMBA Hotel pilot plant, in Lloret the Mar. The stainless steel tubs and frame itself has the main environmental impact contributions in 2 out of 9 impact categories: acidification (48%) and mineral, fossil and renewable resource depletion (86%), due to the process of manufacturing stainless steel (Figure 7). 

Figure 7. Potential environmental impacts of construction stage of VertECO  technology

By taking a look into the Electrochemical Ozonation technology, it can be seen that the environmental impact contributions are distributed among the different life cycle stages analysed: construction stage, operation stage and maintenance stage (see Figure 1). The construction stage has the main environmental impact contributions in 3 out of 9 impact categories: particulate matter (41%), due to the use of aluminium in the rack of the structure; freshwater eutrophication (50%), because of copper of the anolyte and catholyte; and freshwater eco-toxicity (59%) linked also with the use of aluminium in the rack of the structure (Figure 8). The operation stage has the main environmental impact contributions in the following impact categories: acidification (41%), photochemical ozone formation (42%) and marine eutrophication (46%). All those environmental impact contributions are related to electricity consumption, which is the only component included in this stage. Regarding the maintenance stage, it has the main environmental impact contributions also in 3 out of 9 impact categories: climate change (40%), mineral, fossil and renewable resource depletion (53%) and ozone depletion (83%). Those environmental impact contributions are associated to the tetrafluoroethylene content in the IX membrane of the technology (Figure 9). 

Figure 8. Potential environmental impacts of construction stage of Electrochemical ozonation  technology

Figure 9. Potential environmental impacts of maintenance stage of Electrochemical ozonation technology

 Recomendaciones related to environmental impact analysis of demEAUmed technologies

In order to reduce the environmental impacts contributions of the above mentioned technologies - as well as similar technologies- some recommendation are summarised below:

• Optimise and reduce the electricity consumption, or incorporate renewable energy sources, especially for the case of Electrocoagulation Flotation and Photoelectro-Fenton technologies.
• Use alternative materials (e.g. plastic, wood) for the VertECO structure (currently it is made of stainless steel).
• Substitute the aluminium rack of the Electrochemical Ozonation technology by another material with a more environmentally friendly rack.
• Expand the lifespan of some of the Electrochemical Ozonation components, such as the IX membrane or the anolythe and catholyte, or incorporate components manufactured with more environmentally friendly materials.

Socio-Economic assessment of demEAUmed technologies

The Life Cycle Costing (LCC) methodology has been applied in order to know the overall cost of treating one cubic meter (1m³) of greywater or wastewater by the technologies along their life cycle. The LCC analysis includes the cost of all the construction materials and components of each technology, the operation and maintenance costs, including costs related to the electricity consumption, chemicals and reagents, maintenance tasks and replacements of components, etc. Moreover, labour costs linked with work time are also included. At this stage, the costs associated to waste treatment have been excluded. The following table summarizes the total cost of treating 1m³ of greywater or wastewater, by VertECO and Electrochemical Ozonation technologies.

Furthermore, some indicators have been determined to assess the S-LCA, examples are shown below (Figure 10). Currently, the quantification of the socioeconomic impacts and the benefits provided by demEAumed project are being analysed. More efforts will be done during the coming months regarding socio-economic analysis.