This work aimed the study of methane yield using different proportions of primary sludge (PS) and waste activated sludge (WAS) for anaerobic digestion (AD) conversion. Three trials were carried out: T1 (60 : 40, v/v), T2 (80 : 20, v/v) and T3 (100 : 00, v/v) to estimate the best proportion in comparison with a reference scenario, T0 (40 : 60, v/v). AD was performed in mesophilic conditions with a hydraulic retention time (HRT) of 15 days and an organic loading rate (OLR) expressed in total volatile solids (TVS) of 1.62 ± 0.06 kgTVS m−3 day−1. Biogas production for trials T1 and T2 increased from 45 to 71% in comparison with T0. The experimental methane production along trials was used to assess the energy recovery corresponding to increases from 32 to 55%. The most suitable trial to be implemented at real‐scale is T1, applying a lower PS solid retention time combined with an increase of WAS thickening.
This paper presents the study of the occurrence of 10 endocrine-disrupting compounds (EDCs) in 60 water samples using a method for simultaneous quantification and confirmation of the presence of these emerging compounds, using ultra-performance liquid chromatography with electrospray ionization and tandem mass spectrometry (UPLC-ESI-MS/MS). All samples were previously extracted by solid-phase extraction (SPE). Several natural and synthetic hormones (17-β-estradiol, ethinylestradiol, estriol, estrone, progesterone, mestranol, and diethylstilbestrol) and some industrial products (4-n-nonylphenol, 4-tert-octylphenol, and bisphenol A) were chosen for this survey. The analytical limits were calculated for each compound and were used in the identification and quantification of these target compounds in EPAL's water supply system. In this study, several samples were taken from the main intakes of water (surface and groundwater) used for production of water for human consumption and from different sampling points of the drinking water distribution system (piping, nets, and reservoirs). Some target compounds, such as estriol, 4-tert-octylphenol, mestranol, and nonylphenol, were found in trace amounts in several water samples. However, the studied endocrine-disrupting appeared in very low concentrations when compared with the assessed analytical limits.
Anaerobic co-digestion of organic rich wastes and wastewater sludge has become an attractive economic possibility for water utilities as it enhances biogas production. The suitability of the organic rich waste depends on its biodegradability as well as on its synergetic effect on the anaerobic digestion process. The feasibility of sewage sludge (SS) treatment via co-digestion was studied in a semi-continuous mode at mesophilic conditions (36 ± 1 °C), with a hydraulic retention time of 17 days and an average organic loading rate of 0.94 ± 0.05 g VS L reactor day −1 , using the liquid fraction of pre-treated exhausted coffee biowaste (LECB) as a co-substrate. An anaerobic co-digestion trial (T1) was performed using as feeding mixture 80% SS and 20% LECB (v:v) and compared against a reference scenario of mono-digestion of SS (T0). The stability along assays was ensured by monitoring the digestate characteristics (pH, electrical conductivity, total alkalinity and ammonia content) and the specific energy-loading rate (SELR). Along the operation time of T1, methane yield and VS removal were significantly higher in comparison to mono-digestion of SS. Results showed that the addition of the co-substrate had a positive effect on specific methane production (3 times higher) and methane content (12% higher), indicating this is a feasible strategy towards self-sufficient wastewater treatment plants.
The authors of this contribution explain the Portuguese system of actio popularis: according to the authors the most favourable of all with regard to locus standi in environmental matters. They argue that the dichotomy between public and private environmental damage underlying the construction of the right of access to justice is not an accurate representation of the real life social relations concerning the environment. This is where the concept of diffuse interests, adopted in Portuguese constitutional law comes in.
Os direitos dos refugiados assumem uma relevância crescente na atualidade, em consequência do aumento dos movimentos migratórios.As Nações Unidas criaram uma Carta Mundial de Direitos Humanos, onde se inclui o direito de asilo e os direitos dos refugiados, na aprovação da Declaração Universal dos Direitos Humanos2, de dois Pactos Internacionais sobre direitos humanos, da Convenção de Genebra sobre o Estatuto do Refugiado e da Declaração sobre Asilo Territorial.A União Europeia, através do Sistema Europeu Comum de Asilo, tem desenvolvido a proteção internacional de asilo e dos refugiados, que vai para além do que consagra o direito internacional.
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