Performance of first flush devices as sanitary barrier for cisterns protection

• Main Authors: Selma Thaís Bruno da Silva, Luttemberg Ferreira de Araújo, Alice Jadneiza Guilherme de Albuquerque Almeida, Sávia Gavazza, Sylvana Melo dos Santos
• Format: Article
• Language: English
• Published: Associação Brasileira de Águas Subterrâneas 2017-03-01
• Series: Revista Águas Subterrâneas
• Subjects: Captação de água de chuva. Dispositivos de descarte das primeiras águas de chuva. Indicadores microbiológicos. Indicadores físico-químicos.
• Online Access: https://aguassubterraneas.abas.org/asubterraneas/article/view/28658
• ISSN: 0101-7004; 2179-9784

The use of cisterns for rainwater storage is a common practice in several places that have long periods of water scarcity. To avoid contamination of the stored water in cisterns, one strategy is the use of first flush device. In this study, the water quality was analyzed in relation to the physical-chemical parameters and pathogenic microorganisms by passed of the storage system, considering the use of three types of automatic first flush devices: one is based on the water sealing principle (called A1 Device - ANDRADE NETO, 2004), one is based on the principle of communicating vessels (called A2 device - www.cepfs.org) and the other is based on both physical principles (called DesviUFPE - ALVES et al., 2014). Both first flush devices A1 and A2 are made of concrete and the DesviUFPE is made of PVC pipes. In addition, we investigated the quality of water stored in cisterns comparing their results with potability standards. First flush devices are the obligatory passage point between the rain gutters and the cistern for the rainwater. All first flush devices studied resulted in significant improvement in water stored in the cistern, emphasizing the results obtained for real and apparent color, turbidity, total solids, total coliform and E. Coli. It was observed that except for apparent color, turbidity, pH and DO, the other quality parameters analyzed in the cistern without first flush devices were higher than those obtained for the other cisterns, showing the necessity of the use of first flush device.