Search results for "sewage"
showing 10 items of 480 documents
Wastewater treatment in Valencia city (Spain)
1993
Our objective is to determine the changes in the wastewater treatment process in the city of Valencia by taking into account population changes during the period 1983–1990. We have consulted analytical data and information regarding this volume of water treated in a biological treatment plant of activated sludge; data was collected daily and introduced into a data matrix from which the distribution and central tendency measures were calculated. We then obtained the correlations of the different parameters according to population variations. We observed an increase in the volume of water treated during our study period: from 74,220 m3/day in 1983 to 183,850 m3/day in 1990. This was in contra…
Mapping Sediment Accumulation Rate by using Volume magnetic Susceptibility Core Correlation in a contaminated Bay (Lake Geneva, Switzerland)
2003
The Bay of Vidy is the most contaminated area of Lake Geneva: contamination is caused by the effluent of the sewage treatment plant (STP) of the City of Lausanne. The implementation of a chemical stage in the treatment plant to remove phosphorus using FeC13 in 1971 is indirectly recorded in the lake sediments by a strong and sharp increase in the volume magnetic susceptibility (VMS) signal. A total of 43 sediment cores have been retrieved and measured for VMS. The synchronism of the VMS signal increase and its relation to the implementation of the P-removal stage in the STP has been shown in seven 137Cs-dated sediment cores. The VMS signal has been used to date by stratigraphie correlation …
Economic sustainability of hydrothermal liquefaction of sewage sludge: From a conceptual analysis to a practical verification
2022
Introduction: Hydrothermal liquefaction (HTL) could be a promising technology to produce biocrude from wet biomass. A conceptual analysis on the HTL of microalgae assisted by the use of solar heat demonstrated that even if microalgae are one of the most productive and investigated feedstock, their high cost hinders the economic sustainability of the process1. To overcome this issue a zero-cost wet waste biomass like sewage sludge (SS) could be adopted with comparable efficiency. Furthermore, the use of a proper catalyst, promoting the in-situ upgrading of the biocrude, still represents a big challenging opportunity for industrial HTL development. Aim: The outcomes of the conceptual analysis…
Outdoor microalgae-based urban wastewater treatment: recent advances, applications and future perspectives
2021
[EN] Although microalgae-based wastewater treatment has been traditionally carried out in extensive waste stabilization ponds, recent trends focus on the use of microalgae to apply the circular economy principles in the wastewater treatment sector due to the capacity of algae to absorb carbon dioxide while recovering nutrients from sewage. To this aim, the development of new intensive microalgae-based systems with higher efficiency and level of process control is required. Results obtained for these systems at lab scale are generally promising. However, upscaling to outdoor conditions is often uncertain. Some advances have been made in terms of applying open systems at large scale. However,…
Effect of light intensity, light duration and photoperiods in the performance of an outdoor photobioreactor for urban wastewater treatment
2019
[EN] A series of eight experiments were carried out to analyse the effects of light intensity, light duration and photoperiods on a microalgae culture for treating AnMBR effluent at an outdoor photobioreactor (PBR) plant. Improved performance was achieved in terms of nutrient recovery rates, biomass productivity and effluent nutrient concentrations at a higher net photon flux. However, the higher irradiance was also responsible for lower biomass productivity:light irradiance ratios. None of the experiments with different lighting regimes and the same net photon flux showed any significant differences. The data obtained suggest that microalgae performance in this system did not depend on the…
Performance of an outdoor membrane photobioreactor for resource recovery from anaerobically treated sewage
2018
[EN] The objective of this work was to evaluate the performance of a pilot scale membrane photobioreactor (MPBR) for treating the effluent of an anaerobic membrane bioreactor (AnMBR) system. In particular, new experimental data on microalgae productivity, nutrient recovery, CO2 biofixation and energy recovery potential was obtained under different operating conditions, which would facilitate moving towards cost-effective microalgae cultivation on wastewater. To this aim, a 2.2-m(3) MPBR equipped with two commercial-scale hollow-fibre ultrafiltration membrane modules was operated treating the nutrient-loaded effluent from an AnMBR for sewage treatment. The influence of several design, enviro…
Comprehensive assessment of the microalgae-nitrifying bacteria competition in microalgae-based wastewater treatment systems: Relevant factors, evalua…
2022
[EN] Due to their capacity to assimilate carbon dioxide and nutrients, microalgae-based cultivation systems have emerged as a green solution for intensive wastewater treatment. However, when large concentrations of ammonium are present the competition between microalgae and ammonium-oxidising bacteria plays a significant role. Microalgae use ammonium to synthesise proteins, photosynthetic pigments and nucleic acids, while ammonium-oxidising bacteria use it as a source of electrons and oxidise it to nitrite.Several authors have studied the isolated factors that influence microalgae-nitrifying bacteria competition, although a comprehensive analysis of this interesting topic is still lacking. …
Economic and environmental sustainability of submerged anaerobic MBR-based (AnMBR-based) technology as compared to aerobic-based technologies for mod…
2015
[EN] The objective of this study was to assess the economic and environmental sustainability of submerged anaerobic membrane bioreactors (AnMBRs) in comparison with aerobic-based technologies for moderate-/high-loaded urban wastewater (UWW) treatment. To this aim, a combined approach of steady-state performance modelling, life cycle analysis (LCA) and life cycle costing (LCC) was used, in which AnMBR (coupled with an aerobic-based post-treatment) was compared to aerobic membrane bioreactor (AeMBR) and conventional activated sludge (CAS). AnMBR with CAS-based post-treatment for nutrient removal was identified as a sustainable option for moderate-/high-loaded UWW treatment: low energy consump…
A plant-wide energy model for wastewater treatment plants: application to anaerobic membrane bioreactor technology
2016
[EN] The aim of this study is to propose a detailed and comprehensive plant-wide model for assessing the energy demand of different wastewater treatment systems (beyond the traditional activated sludge) in both steady- and unsteady-state conditions. The proposed model makes it possible to calculate power and heat requirements (W and Q, respectively), and to recover both power and heat from methane and hydrogen capture. In order to account for the effect of biological processes on heat requirements, the model has been coupled to the extended version of the BNRM2 plant-wide mathematical model, which is implemented in DESSAS simulation software. Two case studies have been evaluated to assess t…
Environmental impact of submerged anaerobic MBR (SAnMBR) technology used to treat urban wastewater at different temperatures
2013
[EN] The objective of this study was to assess the environmental impact of a submerged anaerobic MBR (SAnMBR) system in the treatment of urban wastewater at different temperatures: ambient temperature (20 and 33 degrees C), and a controlled temperature (33 degrees C). To this end, an overall energy balance (OEB) and life cycle assessment (LCA), both based on real process data, were carried out. Four factors were considered in this study; (1) energy consumption during wastewater treatment; (2) energy recovered from biogas capture; (3) potential recovery of nutrients from the final effluent; and (4) sludge disposal. The OEB and LCA showed SAnMBR to be a promising technology for treating urban…