Author(s): Laura Bonastre; Mateo Bruno Pastur; Sergio Montes; Marta Ganzer; Belen Galofre; Carles Vilaro; Susana Gonzalez; Pau Cardoner

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Keywords: Lage blooms; Quality; Sensors; Drinking Water Treatment Plant

Abstract: Barcelona city has its main origin of water in the Llobregat river. Due to the Mediterranean climate, rising temperatures for climate change and the increase in human activity around the river, the treatment of the water for human consumption purposes is challenging, as the quality characteristics are dynamic and complex. In recent years, an increase in the presence of algae in the river has been detected, which represents a challenge for the Drinking Water Treatment Plant (DWTP) with surface water catchment as algae could cause problems of smell, color and in some cases the generation of toxins in the tap water. The need of an action protocol at the DWTP of Sant Joan Despí (SJD), Barcelona (Spain) is a growing necessity as the number of algae blooms increases every year. The aim of this study is to define a strategy for the monitoring and control of algae blooms in the DWTP of SJD, based on the early detection of algae and an adjusted response to these events. For this purpose, three main tasks have been done: 1.Selection and evaluation of offline and online sensors for algae monitoring in real-time and characterization. Three devices have been used for the detection of algae: an online fluorimeter with chlorophyll a measurement (Trilux, Chelsea technology), an offline fluorimeter with classification of 5 species of algae (AlgaeLabAnalyser, bbe Moldanke) and a flow-imaging microscope for the quantification and classification of the algae (Flowcam, Yokogawa). 2.Historical data processing: With the data generated it’s been studied the behavior of algae in the river in different seasons, the correlation between algae and some physical-chemical parameters, the evolution of algae inside the plant and an identification of algae species. 3.Algal removal experiments: with different doses of disinfectants and coagulant. Jar-test experiments have been carried out to determine strategies for optimal algae removal. It has been tested: two disinfectants (chlorine dioxide and potassium permanganate) and one coagulant (pax-18); in different doses and combinations of reagents and algae. Algae growth have been studied in the Llobregat river and in the DWTP of SJD, seasonal dynamics have been detected and the main species have been identified. It has been determined the action of the disinfectant and the coagulant in the elimination of algae. With all the data generated an action plan for algae bloom in the DWTP of SJD has been defined.

DOI: https://doi.org/10.3850/IAHR-39WC2521711920221661

Year: 2022