Validation of a decision support tool for wastewater treatment selection.

Wastewater treatment selection is a complex task usually addressed by applying separate tools for the correct assessment of multi-criteria evaluation. Novedar_EDSS integrates technical, environmental, economic and social assessment capabilities in one single platform. The aim of this work is to evaluate and demonstrate the capabilities of this environmental decision support system (EDSS). For that purpose, 4 case studies of real projects were selected to validate the results in the EDSS by comparing them with those from the study of alternatives performed by the decision makers. Moreover, 1 conceptual case study was applied to support the selection of the most properly strategy for plant retrofitting. Results have demonstrated that the EDSS provides key aspects when deciding the retrofitting process to apply and, when compared to real projects, it recommends analogue treatments as those applied in the projects, ranking them in the same order. Therefore, results in the validation process performed show that this tool provides a reliable basis to support decision makers to select properly treatment alternatives in wastewater treatment plant pre-design.

Economic valuation of environmental benefits of removing pharmaceutical and personal care products from WWTP effluents by ozonation.

Continuous release of pharmaceutical and personal care products (PPCPs) present in effluents from wastewater treatment plants (WWTPs) is nowadays leading to the adoption of specific measures within the framework of the Directive 2000/60/EC (Water Framework Directive). The ozonation process, normally employed for drinking water production, has also proven its potential to eliminate PPCPs from secondary effluents in spite of their low concentrations. However, there is a significant drawback related with the costs associated with its implementation. This lack of studies is especially pronounced regarding the economic valuation of the environmental benefits associated to avoid the discharge of these pollutants into water bodies. For the first time the shadow prices of 5 PPCPs which are ethynilestradiol, sulfamethoxazole, diclofenac, tonalide and galaxolide from treated effluent using a pilot-scale ozonation reactor have been estimated. From non-sensitive areas their values are -73.73; -34.95; -42.20; -10.98; and -8.67 respectively and expressed in €/kg. They represent a proxy to the economic value of the environmental benefits arisen from undischarged pollutants. This paper contributes to value the environmental benefits of implementing post-treatment processes aimed to achieve the quality standards required by the Priority Substances Directive.

A knowledge management methodology for the integrated assessment of WWTP configurations during conceptual design.

The current complexity involved in wastewater management projects is arising as the XXI century sets new challenges leading towards a more integrated plant design. In this context, the growing number of innovative technologies, stricter legislation and the development of new methodological approaches make it difficult to design appropriate flow schemes for new wastewater projects. Thus, new tools are needed for the wastewater treatment plant (WWTP) conceptual design using integrated assessment methods in order to include different types of objectives at the same time i.e. environmental, economical, technical, and legal. Previous experiences used the decision support system (DSS) methodology to handle the specific issues related to wastewater management, for example, the design of treatment facilities for small communities. However, tools developed for addressing the whole treatment process independently of the plant size, capable of integrating knowledge from many different areas, including both conventional and innovative technologies are not available. Therefore, the aim of this paper is to present and describe an innovative knowledge-based methodology that handles the conceptual design of WWTP process flow-diagrams (PFDs), satisfying a vast number of different criteria. This global approach is based on a hierarchy of decisions that uses the information contained in knowledge bases (KBs) with the aim of automating the generation of suitable WWTP configurations for a specific scenario. Expert interviews, legislation, specialized literature and engineering experience have been integrated within the different KBs, which indeed constitute one of the main highlights of this work. Therefore, the methodology is presented as a valuable tool which provides customized PFD for each specific case, taking into account process unit interactions and the user specified requirements and objectives.

Assessment of wastewater treatment plant design for small communities: environmental and economic aspects.

The preliminary design and economic assessment of small wastewater treatment plants (less than 2000 population equivalent) are issues of particular interest since wastewaters from most of these agglomerations are not covered yet. This work aims to assess nine different technologies set-up for the secondary treatment in such type of facilities embracing both economic and environmental parameters. The main novelty of this work is the combination of an innovative environmental decision support system (EDSS) with a pioneer approach based on the inclusion of the environmental benefits derived from wastewater treatment. The integration of methodologies based on cost-benefit analysis tools with the vast amount of knowledge from treatment technologies contained in the EDSS was applied in nine scenarios comprising different wastewater characteristics and reuse options. Hence, a useful economic feasibility indicator is obtained for each technology including internal and external costs and, for the first time, benefits associated with the environmental damage avoided. This new methodology proved to be crucial for supporting the decision process, contributing to improve the sustainability of new treatment facilities and allows the selection of the most feasible technologies of a wide set of possibilities.