Shaping the new low-energy WRRF: Strategies based on renewable energies

New technologies are quickly re-shaping the energy intensity and operational costs of water resource recovery facilities (WRRFs). The penetration of affordable technologies is embracing concepts as 1) energy storage, 2) renewable resources, and 3) improved energy generation/conversion (CHP, co-digestion), these are impacting the-costly-traditional-energy schemes in wastewater management. A model was developed to quantify the economic and environmental performance to meet the actual energy demand of a WRRF. The potentially-available-renewable (or non-conventional) alternatives were also considered. This work incorporates also daily and seasonal site-specific variations together with existing energy tariff structures. The model was validated with real-case studies and provides an estimate on the overall costs (i.e., Present Net Value) concerning the alternative deployment and the associated environmental impacts (CO2 eq. reduction) for each of the potential alternatives related to the studied plant. Four actual WRRFs were analyzed using the developed model resulting in the identification of strategies that could reduce operational costs by 57%, 67%, 74%, and 75%, and reduce CO2 emissions by 59%, 60%, 70% and 69%.