Forecasting saltwater intrusion volume and sulfate content in a wastewater collection system. Case study: Barreiro/Moita WWTP, Portugal

• Autor(a) principal: Figueiredo, Ana S.
• Data de Publicação: 2021
• Outros Autores: Amaral, Leonor, Pacheco, J.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/131333
• topic: Electrical conductivity; Forecasting models; Saltwater intrusion; Undue inflow; Wastewater collection system; Wastewater treatment plant (WWTP); Global and Planetary Change; Water Science and Technology; Atmospheric Science; Management, Monitoring, Policy and Law; SDG 7 - Affordable and Clean Energy

The presence of salt water from the Tagus Estuary has been identified in the influent at Barreiro/Moita Wastewater Treatment Plant (WWTP), Portugal. The intrusion occurs throughout damaged sections and direct vectors in the wastewater collection system, during high tide levels, changing the wastewater characteristics and impacting the WWTP process. This study designed models to quantify this problem, enabling more effective countermeasures within the right timing. The proposed models estimate the average volume of salt water and sulfate (SO24) load for each high tide period. The laboratory results show strong correlations between the influent electrical conductivity (EC) and percentage of salt water in WWTP inflow (0.9909), and between EC and SO24 concentration in WWTP influent (0.9797). The forecast models also show good correlation between the high tide levels with volume of salt water (0.9145) and SO24 load (0.9162) entering the system. Considering the total monthly inflow, the highest percentage of salt water registered in WWTP inflow was 3.6%. During high tide periods, critical situations have been assessed with up to 53.9% of salt water in the WWTP inflow, increasing energy consumption and costs in pumping stations.