4. Environmental and economic impact of the HRAP process

The HRAP system differs from conventional water treatment systems in terms of energy consumption, the nature and quantity of gases emitted, the surface area required and cost. Lifecycle analyses provide a detailed assessment of the environmental impact of a system throughout its construction, operation and dismantling, taking into account material acquisition, production, transport, use and waste disposal. This section is based on five studies that have carried out life-cycle analyses of large-scale HRAP systems compared with conventional wastewater treatment systems such as activated sludge, in order to estimate the order of magnitude of energy consumption, greenhouse gas emissions and surface area required, as well as the investment and operating costs associated with HRAP system operation.