The focus of this project was the resource efficiency of Irish wastewater treatment plants (WWTPs). The perspective of the report is both operational (economic) and environmental. Wastewater treatment is a resource-intensive process, with three main resources being identified as those of greatest concern: energy, chemicals and water. According to the United States Environmental Protection Agency, wastewater treatment accounts for approximately 1% of the world’s total energy consumption and 3% of the electrical load in the USA (USEPA, 2010). This current estimation is mirrored in Europe, in which energy consumption is expected to increase significantly as a result of population growth and increasing environmental standards (Olsson, 2012a). These figures should be seen in the context of the highly underdeveloped wastewater infrastructures in many countries and the expected increases in energy consumption resulting from new investments and regulations.
The United Nations and World Health Organization estimate that 32% of the world’s population lack improved sanitation facilities (Unicef, 2015), while many countries with wastewater infrastructures require significant investment. Meanwhile, in the USA, increases in WWTP energy consumption of over 20% are expected by 2020 (USEPA, 2010), whereas a second European source predicts “conservative” increases of 60 to 100% over the next 15 years to meet the new EU directives (Olsson, 2012a). Some wastewater treatment companies in the UK have reported increases in electricity usage of 60% since 1990 (Olsson, 2012a)