Alternative processes are available for both wastewater treatment at sewage works and drinking water preparation at water production plants. Some of these involve greater use of chemicals and auxiliary materials, and an important issue is therefore how the energy savings achieved with a particular option compare with the energy required to produce the auxiliaries in question.
Against this background a study was carried out to assess the energy consumption of auxiliaries production. For the auxiliaries most frequently used the following were determined:
- the energy impact of production, expressed as the Gross Energy Requirements (GER) of the materials in question, broken down into renewable versus non-renewable energy;
- the environmental impact of production, expressed as a single indicator according to the ReCiPe methodology.
The report also provides ‘user recommendations’ for the calculated values (what they should and should not be used for) and an explanation of the methodology used.
The study dovetails with the STOWA research programme 'The Energy Plant', a study exploring the potential for reducing the energy consumption of sewage works to such an extent as to make them net suppliers of energy.