Life cycle assessment of different scenarios for pigment production from an algal turf scrubber (ATS) system

The application of algal turf scrubber (ATS) systems for simultaneous bioremediation and biomass valorization can promote the mitigation of nitrogen, phosphorus, and organic contaminants in water bodies, helping reduce both the environmental impacts and the costs related to bioactive compound production. The present study performed a life cycle assessment (LCA) based on the production of pigments from the periphytic biomass at a pilot-scale ATS system (SISGEN register A256CC3). For the LCA, the functional unit was defined as 10 kg of pigments, and 10 years was considered the reference flow. The Ecoinvent 3 database and IMPACT 2002 + (V2.10) were used in SimaPro software (version 8.04) with data from the ATS system cultivation (construction and operation), drying, and pigment extraction. As a result, the damages and impacts of most categories were mainly related to the drying step, followed by extraction. However, even when considering a permanent demand for electricity (for the hydraulic pump), the operation of the ATS system presented fewer impacts in its construction and operation than traditional cultivation systems. Additionally, applying an ATS system to produce biomass for pigment extraction had low impacts on most categories, mainly due to water use from a catchment lake. New scenarios are proposed to minimize impacts, indicating that the ATS system with solar drying can be an interesting option to produce pigments from periphytic biomass simultaneously and promote polluted lake bioremediation. Graphical Abstract