Search results for "Activated Sludge"
showing 10 items of 143 documents
Improvement of the thermophilic anaerobic digestion and hygienisation of waste activated sludge by synergistic pretreatment
2019
Hybrid disintegration of waste activated sludge (WAS) before the thermophilic anaerobic stabilization of WAS contributes to the intensification of organic compounds decomposition and increases the effectiveness of the anaerobic stabilization process compared to the fermentation of raw WAS. This article investigates the influence of a chemical-thermal pretreatment procedure with the use of NaOH and freezing by the dry ice on WAS. We found that the hybrid pretreatment of WAS causes higher concentration of released organics in the liquid phase (represented here as a change in soluble chemical oxygen demand - SCOD value) in comparison to these disintegration techniques used separately. The use …
Comparison of Activated Sludge Processes at Different Temperatures: 35°C, 27–55°C, and 55°C
2002
The performance of mesophilic (35°C; referred to as R1) and thermophilic (55°C; R3) laboratory activated sludge processes (ASPs) as well as ASP with a fluctuating temperature (27-56°C; R2) was compared. During the 124-day runs, in R1 and R3 hydraulic retention time was gradually reduced from 18 h to 3 h, corresponding to an increase in volumetric loading rate from 2 to 10 kg soluble COD m−3d−1; in R2 hydraulic retention time was gradually reduced from 18 to 4.5 h, corresponding to an increase in volumetric loading rate from 2 to 7.5 kg soluble COD m−3d−1. R1 removed on average 85% of soluble COD (GF50-filtered) that was approximately 10% more than R3. In R2 SCOD removal was dependent on the…
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…
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…
Micropollutants removal in an anaerobic membrane bioreactor and in an aerobic conventional treatment plant
2012
The paper expresses an attempt to tackle the problem due to the presence of micropollutants in wastewater which may be able to disrupt the endocrine system of some organisms. These kinds of compounds are ubiquitously present in municipal wastewater treatment plant (WWTP) effluents. The aim of this paper is to compare the fate of the alkylphenols-APs (4-(tert-octyl)) phenol, t-nonylphenol and 4-p-nonylphenol and the hormones (estrone, 17ß-estradiol and 17¿-ethinylestradiol) in a submerged anaerobic membrane bioreactor (SAMBR) pilot plant and in a conventional activated sludge wastewater treatment plant (CTP). The obtained results are also compared with the results obtained in a previous stud…
Direct chromatographic study of the enantioselective biodegradation of ibuprofen and ketoprofen by an activated sludge
2018
[EN] The quantification of the enantiomeric fraction (EF) during the biodegradation process is essential for environmental risk assessment. In this paper the enantioselective biodegradation of ibuprofen, IBU, and ketoprofen, KET, two of the drugs most consumed, was evaluated. Biodegradation experiments were performed in batch mode using a minimal salts medium inoculated with an activated sludge (collected from a Valencian Waste Water Treatment Plant) and supplemented with the racemate of each compound. The inoculum activity was verified using fluoxetine as reference compound. The experimental conditions used (analyte concentration and volume of inoculum) were chosen according to OECD guidel…
Distinguishing the roles of carrier and biofilm in filtering media for the removal of pharmaceutical compounds from wastewater
2017
Abstract Pharmaceutical compounds (PCs) represent a large group of micropollutants in wastewaters (WW) worldwide. Many PCs are resistant to conventional WW treatment. Moreover, for some PCs the removal process is reversible. The aim of this study was to test three newly developed ceramic carriers for biofilm formation and PCs removal. The testing of untreated WW samples by liquid chromatography coupled to Orbitrap mass spectrometry allowed to detect the occurrence of 18 PCs in the range from 26 ng/L to 20,688 ng/L, with the highest concentrations found for caffeine. Besides, among PCs with concentrations above 1,000 ng/L, ibuprofen (19,234 ng/L), naproxen (1,405 ng/L), xylazine (1,366 ng/L)…
Membrane Bioreactors for wastewater reuse: Respirometric assessment of biomass activity during a two year survey
2018
Abstract Stricter effluent limits, water shortage conditions, land availability requires today even more the needs of advanced wastewater treatments. Attractive solutions come from membrane bioreactors (MBR), Integrated Fixed Film Activated Sludge (IFAS) or combinations (i.e., IFAS-MBRs). One crucial aspect for the applicability of this overall new technology, compared to the conventional activated sludge systems, is the lack of knowledge for design and manage (e.g., kinetic constants, optimal operative conditions etc.). In view of the above frame, the aim of the present study was to assess the kinetic and stoichiometric parameters of bacterial species in MBRs by means of respirometric tech…
Membrane bioreactors sludge: From production to disposal
2020
Abstract This chapter reviews the MBR activated sludge from production to disposal. Starting from sludge characterization, the chapter first presents the features of MBR sludge (morphology and EPS chemical composition), also in terms of differences with the activated sludge from conventional activated sludge plants. Sludge dewaterability is then discussed, focusing on the differences between aerobically and anaerobically digested sludge. An analysis of the costs related to MBR sludge treatment and disposal also is presented in order to provide a framework for a sustainable MBR sludge management.