Artigos de Revista

A powdered activated carbon (PAC)/ceramic microfiltration (MF) pilot was operated (24/7) in a water treatment plant during 18 months, with water from different points of the treatment line (raw, ozonated with recirculated filter-backwash waters, ozonated/pre-coagulated, filtered), the testing including MF and PAC/MF. The optimization of PAC/MF operational performance, including PAC effect analysis and pretreatment required, and a cost analysis are herein presented. A new indicator was developed and explored for performance assessment and optimization, the treatment capacity (TCp), i.e. the design flowrate normalized to membrane area and intake pressure. As expected, a higher TCp was obtained with filtered water. Non-clarified waters required alum-coagulation pretreatment to minimize membrane fouling, and achieved similar TCp results among them. PAC addition (6-24 mg/L) did not promote membrane fouling and had no or a slight positive effect on TCp. TCp integrates all key aspects of process productivity and therefore constitutes a useful indicator to balance flux, energy consumption, backwash frequency and chemical cleaning frequency. The cost functions developed for PAC/MF yielded, for the best operating conditions found for the low-turbidity, low-dissolved organic content waters tested, a total cost of 0.07-0.11 

Urban water utilities face growing challenges in compliance with increasingly demanding legislation, tightening budgets, ageing personnel, decreasing infrastructure reliability, increasing operational costs, regulatory pressure, and climate change. Within this context, tracking the alignment of the performance with the mission and strategic objectives of the organization, based on reliable and up-to-date data, is of utmost importance to enable effective and continual improvement management. Organizational performance assessment in the water sector has been a topic of growing attention since the 1990s due to the increase in the role of regulators and tighter legislation. Proactive utilities are incorporating sustainability, resource efficiency, resilience, and continual improvement principles in their practices. Strategic planning provides the road map for management and interconnecting the different areas of the organization. An essential component of strategic management planning is the adoption of a tailored performance assessment system (PAS), allowing a better response to these challenges from the water utility management perspective. This paper presents a novel PAS at the strategic level, which was tested and validated with wastewater utilities, in a co-creation process. The proposed PAS fully adopts the objectives recommended in international standards, with a corresponding set of criteria and metrics, and a validated proposal of reference values for the metrics.