Leonor Amaral

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 () 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 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 load (0.9162) entering the system. Considering the total monthly inflow, the highest percent...

Salt water from the Tagus Estuary has been identified in the influent at Barreiro/Moita Wastewater Treatment Plant (WWTP), Portugal. The saltwater intrusion occurs during high tide levels in the estuary throughout damaged sections and direct vectors in the sewer network, changing the wastewater characteristics impacting the WWTP processes. This work has designed a methodology to assess from which tide level in the Tagus Estuary saltwater intrusion occurs in the sewer network by measuring WWTP influent's electric conductivity (EC). The methodology identifies saltwater intrusion for tide levels higher than 3.10 m, increasing significantly for tide levels higher than 4.00 m. During this study, 86% of the days registered at least one high tide level higher than 3.10 m, and 8% higher than 4.00 m, demonstrating a considerable occurrence of saltwater intrusion in the system with a tendency to increase due to the mean sea level rise registered in the Tagus Estuary. To prevent it, it is ...

Wastewater treatment plants (WWTIP) are a potential source of microplastics [1,2]. Several types of microplastics, namely microbeads, fibres and fragments, were analysed in two WWTP effluent serving different Portuguese communities. A bigger station treating mixed domestic and industrial wastewater averaging 18000 m day and a smaller station with treating mostly domestic wastewater averaging 7250 m day. A total of 6065 microplastics were observed in 5,5 litres of wastewater sampled. 90% of the microplastics analysed were fragments and 88% were collected from treated effluent (1687 items in average per litre). Fibres presented a higher percentage in the affluent (88%), comparing to treated effluent (12%). Regarding sizes, microplastics with less than 0, 5 mm were the most representative in both WWTP. Fibres with 1 to 2 mm were more common. This study intends to contribute with a standardized methodology to analyse microplastics in wastewater, from sampling to identification, measuring and handling processes in the laboratory.

The presence of micropollutants that include endocrine-disrupting compounds (EDC) in aquatic environments is currently one of the most relevant aspects of water quality due to their adverse effects on aquatic organisms and human health. From the several categories of EDC, 17β-estradiol (E2) is a natural hormone, which is prevalent in vertebrates, associated with the female reproductive system and maintenance of the sexual characters. 17α-Ethinylestradiol (EE2) is a synthetic hormone produced from the natural hormone E2 and is an essential component of oral contraceptives. These compounds are susceptible to bioconcentration and have high potential to bioaccumulation. Wastewater treatment plants are the main point source of E2 and EE2 into aquatic environments, but conventional wastewater treatment systems are not specifically designed for steroid removal. To overcome this problem, biological tertiary treatment may be a solution for the removal of emergent pollutants such as E2 and EE...

ABSTRACT In this work we present a preliminary assessment on some landfills from Portugal through following the content in the upflown and dowflown leachate of four target analytes: camphor, octylphenol, diethylphthalate and tributylphosphate. In addition we have tried to simplify the sample treatment using ultrasonic energy in the solid-liquid extraction from the extracting (C 18) column. We have found camphor and octylphenol in the leachates studied whilst diethylphthalate and tributylphosphate were below our detection limits. The use of ultrasonic energy was found inadequate because artifacts were formed that interfere in the subsequent analysis. Some of the landfill leachate treatment plants surveyed are able to diminish the target compounds at the effluent. On the overall our results suggest that it is necessary to undergo a detailed survey in Portugal regarding the performance of landfills plant treatments and its impact in the environment or the nearby zones.

ABSTRACT Constructed wetlands (CW) are sustainable wastewater treatment processes, especially for small communities. In order to evaluate the effect of mass loading rates and the presence of plants on the removal of organic matter and ammonia in horizontal subsurface flow CW, two set of experiments were carried out at different organic and ammonia loading rates in two mesocosms, one without plants, other colonized with Phragmites australis. Regardless the mass loading rates, the COD removal was significantly greater in the bed containing plants (70.3% and 75.6%, respectively, for the lower and the higher organic loads) than in the bed without plants (38.5% and 44.4%, respectively). The removal of NH4-N was also significantly higher in the planted bed (59.3% and 47.8%, respectively, for the lower and the higher nitrogen loads) than in bed without plants (34% and 33%, respectively). The removal of organic matter and ammonia was higher in the first section of the bed (first 33 cm) in the unplanted system (> 75%) and was more distributed through the bed in the planted system, which seems to have been associated with the growth of roots and rhizomes that support the biofilm as well as the release of oxygen in the root zone.

17β-Estradiol (E2) is a natural estrogen produced by the feminine endocrine system. It is excreted mainly through urine and feces. Exposure to E2 may affect the reproductive system of both animals and humans, especially since the removal of E2 in conventional processes and technologies present in the wastewater treatment plants is not sufficient. Chlorine is one of the most studied and used oxidant worldwide. Although there are studies that demonstrate the endocrine disrupting compounds removal like E2, its reaction with organic matter can originate by-products, namely, trihalomethanes, which are known to have high toxic potential. The main aim of the present study was to evaluate the removal of E2 (50 μg E2 L −1 —maximum concentration) using peracetic acid (PAA), a seeming cleaner and innocuous alternative to chlorine. To this end, a series of jar tests were performed, using different peracetic acid concentrations (1, 5, 10, and 15 mg L −1 ) and contact times (10, 15, and 20 min). The results obtained showed that a peracetic acid concentration of 15 mg L −1 with a contact time of 20 min had a removal efficacy of approximately 100%. The second main goal of this study was to evaluate the ecotoxicological potential of the tested treatments on the zebrafish Danio rerio . Several oxidative stress biomarkers were evaluated, namely glutathione S -transferase, lipid peroxidation, and catalase, besides vitellogenin. Both peracetic acid and E2 caused significant increases in the oxidative stress biomarkers, although this did not lead to increased lipid peroxidation levels. In addition, peracetic acid significantly decreased the estrogenic activity of E2, as indicated by decreased vitellogenin levels. Peracetic acid demonstrated to have great potential as an alternative disinfectant for chlorine treatments, and indications for future research are discussed.