Assessing the effects of tertiary treated wastewater reuse on the presence emerging contaminants in a Mediterranean river (Llobregat,NE Spain)

Purpose  

The Llobregat River, which is characterized by important fluctuations of the flow rates, receives treated waters from WWTPs. During the years 2007 and 2008, the Llobregat River basin suffered from a severe drought which affected the supply of drinking water facilities (DWF) that rely on the exploitation of the river water. The Catalan Water Agency implemented a water reuse experiment with the objective of maintaining the river flow rate at sufficiently high level so as to ensure the supply of raw water to Barcelona’s major DWF.     

Assessing the effects of tertiary treated wastewater reuse on a Mediterranean river (Llobregat,NE Spain), part III: pathogens and indicators

Purpose  

Need, coupled with advances in water treatment technology, is motivating a growing interest in augmenting drinking water supplies with reclaimed water. Using reclaimed water to increase the flow of the Llobregat River upstream the water catchment site of the complex multi-step drinking water treatment plant of Sant Joan Despí has been considered. The impact of reclaimed water discharges on the load of E. coli, spores of sulphite-reducing clostridia, somatic coliphages, cytopathogenic enteroviruses, and total and infectious Cryptosporidium oocysts in the Llobregat River water was assessed to gain information for funded decisions in potential future emergencies.     

Occurrence and fate of alkylphenols and alkylphenol ethoxylates in sewage treatment plants and impact on receiving waters along the Ter River (Catalonia, NE Spain)

The partitioning of alkylphenols in the dissolved and particulate matter of influents, effluents, accumulation onto sludge and the impact of sewage treatment plant upon receiving waters was studied along the Ter River basin (Catalonia, NE Spain). A solid-phase extraction or pressurized liquid extraction followed by liquid chromatography-mass spectrometry was developed and permitted to determine target compounds with high efficiency in waters, particulate material and sludge. Nonylphenol mono- and diethoxylate, nonylphenol and octylphenol partitioned preferably upon particulate matter and sludge, whereas long chain NPE(3-15)O prevailed in the dissolved phase and was released by effluents. Within the treatment process, a net accumulation of alkylphenols in sludge was found, producing up to 148g/t/month. The removal efficiency of alkylphenols was of 37-90% and depended on the treatment. Assessment on the fate of these contaminants within STPs is discussed in terms of flow rates, biological oxygen demand and tons of sludge produced.